summaryrefslogtreecommitdiffstats
path: root/kernel
Commit message (Collapse)AuthorAgeFilesLines
* kernel/extable.c: use address-of operator on section symbolsNathan Chancellor2023-06-091-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 63174f61dfaef58dc0e813eaf6602636794f8942 upstream. Clang warns: ../kernel/extable.c:37:52: warning: array comparison always evaluates to a constant [-Wtautological-compare] if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) { ^ 1 warning generated. These are not true arrays, they are linker defined symbols, which are just addresses. Using the address of operator silences the warning and does not change the resulting assembly with either clang/ld.lld or gcc/ld (tested with diff + objdump -Dr). Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://github.com/ClangBuiltLinux/linux/issues/892 Link: http://lkml.kernel.org/r/20200219202036.45702-1-natechancellor@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* perf/core: Fix hardlockup failure caused by perf throttleYang Jihong2023-05-171-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 15def34e2635ab7e0e96f1bc32e1b69609f14942 ] commit e050e3f0a71bf ("perf: Fix broken interrupt rate throttling") introduces a change in throttling threshold judgment. Before this, compare hwc->interrupts and max_samples_per_tick, then increase hwc->interrupts by 1, but this commit reverses order of these two behaviors, causing the semantics of max_samples_per_tick to change. In literal sense of "max_samples_per_tick", if hwc->interrupts == max_samples_per_tick, it should not be throttled, therefore, the judgment condition should be changed to "hwc->interrupts > max_samples_per_tick". In fact, this may cause the hardlockup to fail, The minimum value of max_samples_per_tick may be 1, in this case, the return value of __perf_event_account_interrupt function is 1. As a result, nmi_watchdog gets throttled, which would stop PMU (Use x86 architecture as an example, see x86_pmu_handle_irq). Fixes: e050e3f0a71b ("perf: Fix broken interrupt rate throttling") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230227023508.102230-1-yangjihong1@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* ring-buffer: Sync IRQ works before buffer destructionJohannes Berg2023-05-171-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 675751bb20634f981498c7d66161584080cc061e upstream. If something was written to the buffer just before destruction, it may be possible (maybe not in a real system, but it did happen in ARCH=um with time-travel) to destroy the ringbuffer before the IRQ work ran, leading this KASAN report (or a crash without KASAN): BUG: KASAN: slab-use-after-free in irq_work_run_list+0x11a/0x13a Read of size 8 at addr 000000006d640a48 by task swapper/0 CPU: 0 PID: 0 Comm: swapper Tainted: G W O 6.3.0-rc1 #7 Stack: 60c4f20f 0c203d48 41b58ab3 60f224fc 600477fa 60f35687 60c4f20f 601273dd 00000008 6101eb00 6101eab0 615be548 Call Trace: [<60047a58>] show_stack+0x25e/0x282 [<60c609e0>] dump_stack_lvl+0x96/0xfd [<60c50d4c>] print_report+0x1a7/0x5a8 [<603078d3>] kasan_report+0xc1/0xe9 [<60308950>] __asan_report_load8_noabort+0x1b/0x1d [<60232844>] irq_work_run_list+0x11a/0x13a [<602328b4>] irq_work_tick+0x24/0x34 [<6017f9dc>] update_process_times+0x162/0x196 [<6019f335>] tick_sched_handle+0x1a4/0x1c3 [<6019fd9e>] tick_sched_timer+0x79/0x10c [<601812b9>] __hrtimer_run_queues.constprop.0+0x425/0x695 [<60182913>] hrtimer_interrupt+0x16c/0x2c4 [<600486a3>] um_timer+0x164/0x183 [...] Allocated by task 411: save_stack_trace+0x99/0xb5 stack_trace_save+0x81/0x9b kasan_save_stack+0x2d/0x54 kasan_set_track+0x34/0x3e kasan_save_alloc_info+0x25/0x28 ____kasan_kmalloc+0x8b/0x97 __kasan_kmalloc+0x10/0x12 __kmalloc+0xb2/0xe8 load_elf_phdrs+0xee/0x182 [...] The buggy address belongs to the object at 000000006d640800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 584 bytes inside of freed 1024-byte region [000000006d640800, 000000006d640c00) Add the appropriate irq_work_sync() so the work finishes before the buffers are destroyed. Prior to the commit in the Fixes tag below, there was only a single global IRQ work, so this issue didn't exist. Link: https://lore.kernel.org/linux-trace-kernel/20230427175920.a76159263122.I8295e405c44362a86c995e9c2c37e3e03810aa56@changeid Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 15693458c4bc ("tracing/ring-buffer: Move poll wake ups into ring buffer code") Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* cgroup/cpuset: Wake up cpuset_attach_wq tasks in cpuset_cancel_attach()Waiman Long2023-04-201-1/+3
| | | | | | | | | | | | | | | | | | | commit ba9182a89626d5f83c2ee4594f55cb9c1e60f0e2 upstream. After a successful cpuset_can_attach() call which increments the attach_in_progress flag, either cpuset_cancel_attach() or cpuset_attach() will be called later. In cpuset_attach(), tasks in cpuset_attach_wq, if present, will be woken up at the end. That is not the case in cpuset_cancel_attach(). So missed wakeup is possible if the attach operation is somehow cancelled. Fix that by doing the wakeup in cpuset_cancel_attach() as well. Fixes: e44193d39e8d ("cpuset: let hotplug propagation work wait for task attaching") Signed-off-by: Waiman Long <longman@redhat.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Cc: stable@vger.kernel.org # v3.11+ Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ring-buffer: Fix race while reader and writer are on the same pageZheng Yejian2023-04-201-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6455b6163d8c680366663cdb8c679514d55fc30c upstream. When user reads file 'trace_pipe', kernel keeps printing following logs that warn at "cpu_buffer->reader_page->read > rb_page_size(reader)" in rb_get_reader_page(). It just looks like there's an infinite loop in tracing_read_pipe(). This problem occurs several times on arm64 platform when testing v5.10 and below. Call trace: rb_get_reader_page+0x248/0x1300 rb_buffer_peek+0x34/0x160 ring_buffer_peek+0xbc/0x224 peek_next_entry+0x98/0xbc __find_next_entry+0xc4/0x1c0 trace_find_next_entry_inc+0x30/0x94 tracing_read_pipe+0x198/0x304 vfs_read+0xb4/0x1e0 ksys_read+0x74/0x100 __arm64_sys_read+0x24/0x30 el0_svc_common.constprop.0+0x7c/0x1bc do_el0_svc+0x2c/0x94 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180 Then I dump the vmcore and look into the problematic per_cpu ring_buffer, I found that tail_page/commit_page/reader_page are on the same page while reader_page->read is obviously abnormal: tail_page == commit_page == reader_page == { .write = 0x100d20, .read = 0x8f9f4805, // Far greater than 0xd20, obviously abnormal!!! .entries = 0x10004c, .real_end = 0x0, .page = { .time_stamp = 0x857257416af0, .commit = 0xd20, // This page hasn't been full filled. // .data[0...0xd20] seems normal. } } The root cause is most likely the race that reader and writer are on the same page while reader saw an event that not fully committed by writer. To fix this, add memory barriers to make sure the reader can see the content of what is committed. Since commit a0fcaaed0c46 ("ring-buffer: Fix race between reset page and reading page") has added the read barrier in rb_get_reader_page(), here we just need to add the write barrier. Link: https://lore.kernel.org/linux-trace-kernel/20230325021247.2923907-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: 77ae365eca89 ("ring-buffer: make lockless") Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* perf/core: Fix the same task check in perf_event_set_outputKan Liang2023-04-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 24d3ae2f37d8bc3c14b31d353c5d27baf582b6a6 ] The same task check in perf_event_set_output has some potential issues for some usages. For the current perf code, there is a problem if using of perf_event_open() to have multiple samples getting into the same mmap’d memory when they are both attached to the same process. https://lore.kernel.org/all/92645262-D319-4068-9C44-2409EF44888E@gmail.com/ Because the event->ctx is not ready when the perf_event_set_output() is invoked in the perf_event_open(). Besides the above issue, before the commit bd2756811766 ("perf: Rewrite core context handling"), perf record can errors out when sampling with a hardware event and a software event as below. $ perf record -e cycles,dummy --per-thread ls failed to mmap with 22 (Invalid argument) That's because that prior to the commit a hardware event and a software event are from different task context. The problem should be a long time issue since commit c3f00c70276d ("perk: Separate find_get_context() from event initialization"). The task struct is stored in the event->hw.target for each per-thread event. It is a more reliable way to determine whether two events are attached to the same task. The event->hw.target was also introduced several years ago by the commit 50f16a8bf9d7 ("perf: Remove type specific target pointers"). It can not only be used to fix the issue with the current code, but also back port to fix the issues with an older kernel. Note: The event->hw.target was introduced later than commit c3f00c70276d. The patch may cannot be applied between the commit c3f00c70276d and commit 50f16a8bf9d7. Anybody that wants to back-port this at that period may have to find other solutions. Fixes: c3f00c70276d ("perf: Separate find_get_context() from event initialization") Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Zhengjun Xing <zhengjun.xing@linux.intel.com> Link: https://lkml.kernel.org/r/20230322202449.512091-1-kan.liang@linux.intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* sched_getaffinity: don't assume 'cpumask_size()' is fully initializedLinus Torvalds2023-04-052-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 6015b1aca1a233379625385feb01dd014aca60b5 ] The getaffinity() system call uses 'cpumask_size()' to decide how big the CPU mask is - so far so good. It is indeed the allocation size of a cpumask. But the code also assumes that the whole allocation is initialized without actually doing so itself. That's wrong, because we might have fixed-size allocations (making copying and clearing more efficient), but not all of it is then necessarily used if 'nr_cpu_ids' is smaller. Having checked other users of 'cpumask_size()', they all seem to be ok, either using it purely for the allocation size, or explicitly zeroing the cpumask before using the size in bytes to copy it. See for example the ublk_ctrl_get_queue_affinity() function that uses the proper 'zalloc_cpumask_var()' to make sure that the whole mask is cleared, whether the storage is on the stack or if it was an external allocation. Fix this by just zeroing the allocation before using it. Do the same for the compat version of sched_getaffinity(), which had the same logic. Also, for consistency, make sched_getaffinity() use 'cpumask_bits()' to access the bits. For a cpumask_var_t, it ends up being a pointer to the same data either way, but it's just a good idea to treat it like you would a 'cpumask_t'. The compat case already did that. Reported-by: Ryan Roberts <ryan.roberts@arm.com> Link: https://lore.kernel.org/lkml/7d026744-6bd6-6827-0471-b5e8eae0be3f@arm.com/ Cc: Yury Norov <yury.norov@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* sched/fair: Sanitize vruntime of entity being migratedVincent Guittot2023-04-052-11/+47
| | | | | | | | | | | | | | | | | | | | | | commit a53ce18cacb477dd0513c607f187d16f0fa96f71 upstream. Commit 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed") fixes an overflowing bug, but ignore a case that se->exec_start is reset after a migration. For fixing this case, we delay the reset of se->exec_start after placing the entity which se->exec_start to detect long sleeping task. In order to take into account a possible divergence between the clock_task of 2 rqs, we increase the threshold to around 104 days. Fixes: 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed") Originally-by: Zhang Qiao <zhangqiao22@huawei.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Zhang Qiao <zhangqiao22@huawei.com> Link: https://lore.kernel.org/r/20230317160810.107988-1-vincent.guittot@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sched/fair: sanitize vruntime of entity being placedZhang Qiao2023-04-051-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 829c1651e9c4a6f78398d3e67651cef9bb6b42cc upstream. When a scheduling entity is placed onto cfs_rq, its vruntime is pulled to the base level (around cfs_rq->min_vruntime), so that the entity doesn't gain extra boost when placed backwards. However, if the entity being placed wasn't executed for a long time, its vruntime may get too far behind (e.g. while cfs_rq was executing a low-weight hog), which can inverse the vruntime comparison due to s64 overflow. This results in the entity being placed with its original vruntime way forwards, so that it will effectively never get to the cpu. To prevent that, ignore the vruntime of the entity being placed if it didn't execute for much longer than the characteristic sheduler time scale. [rkagan: formatted, adjusted commit log, comments, cutoff value] Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com> Co-developed-by: Roman Kagan <rkagan@amazon.de> Signed-off-by: Roman Kagan <rkagan@amazon.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230130122216.3555094-1-rkagan@amazon.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* bpf: Adjust insufficient default bpf_jit_limitDaniel Borkmann2023-04-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 10ec8ca8ec1a2f04c4ed90897225231c58c124a7 ] We've seen recent AWS EKS (Kubernetes) user reports like the following: After upgrading EKS nodes from v20230203 to v20230217 on our 1.24 EKS clusters after a few days a number of the nodes have containers stuck in ContainerCreating state or liveness/readiness probes reporting the following error: Readiness probe errored: rpc error: code = Unknown desc = failed to exec in container: failed to start exec "4a11039f730203ffc003b7[...]": OCI runtime exec failed: exec failed: unable to start container process: unable to init seccomp: error loading seccomp filter into kernel: error loading seccomp filter: errno 524: unknown However, we had not been seeing this issue on previous AMIs and it only started to occur on v20230217 (following the upgrade from kernel 5.4 to 5.10) with no other changes to the underlying cluster or workloads. We tried the suggestions from that issue (sysctl net.core.bpf_jit_limit=452534528) which helped to immediately allow containers to be created and probes to execute but after approximately a day the issue returned and the value returned by cat /proc/vmallocinfo | grep bpf_jit | awk '{s+=$2} END {print s}' was steadily increasing. I tested bpf tree to observe bpf_jit_charge_modmem, bpf_jit_uncharge_modmem their sizes passed in as well as bpf_jit_current under tcpdump BPF filter, seccomp BPF and native (e)BPF programs, and the behavior all looks sane and expected, that is nothing "leaking" from an upstream perspective. The bpf_jit_limit knob was originally added in order to avoid a situation where unprivileged applications loading BPF programs (e.g. seccomp BPF policies) consuming all the module memory space via BPF JIT such that loading of kernel modules would be prevented. The default limit was defined back in 2018 and while good enough back then, we are generally seeing far more BPF consumers today. Adjust the limit for the BPF JIT pool from originally 1/4 to now 1/2 of the module memory space to better reflect today's needs and avoid more users running into potentially hard to debug issues. Fixes: fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K") Reported-by: Stephen Haynes <sh@synk.net> Reported-by: Lefteris Alexakis <lefteris.alexakis@kpn.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://github.com/awslabs/amazon-eks-ami/issues/1179 Link: https://github.com/awslabs/amazon-eks-ami/issues/1219 Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20230320143725.8394-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* ftrace: Fix invalid address access in lookup_rec() when index is 0Chen Zhongjin2023-03-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ee92fa443358f4fc0017c1d0d325c27b37802504 upstream. KASAN reported follow problem: BUG: KASAN: use-after-free in lookup_rec Read of size 8 at addr ffff000199270ff0 by task modprobe CPU: 2 Comm: modprobe Call trace: kasan_report __asan_load8 lookup_rec ftrace_location arch_check_ftrace_location check_kprobe_address_safe register_kprobe When checking pg->records[pg->index - 1].ip in lookup_rec(), it can get a pg which is newly added to ftrace_pages_start in ftrace_process_locs(). Before the first pg->index++, index is 0 and accessing pg->records[-1].ip will cause this problem. Don't check the ip when pg->index is 0. Link: https://lore.kernel.org/linux-trace-kernel/20230309080230.36064-1-chenzhongjin@huawei.com Cc: stable@vger.kernel.org Fixes: 9644302e3315 ("ftrace: Speed up search by skipping pages by address") Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Add NULL checks for buffer in ring_buffer_free_read_page()Jia-Ju Bai2023-03-111-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 3e4272b9954094907f16861199728f14002fcaf6 ] In a previous commit 7433632c9ff6, buffer, buffer->buffers and buffer->buffers[cpu] in ring_buffer_wake_waiters() can be NULL, and thus the related checks are added. However, in the same call stack, these variables are also used in ring_buffer_free_read_page(): tracing_buffers_release() ring_buffer_wake_waiters(iter->array_buffer->buffer) cpu_buffer = buffer->buffers[cpu] -> Add checks by previous commit ring_buffer_free_read_page(iter->array_buffer->buffer) cpu_buffer = buffer->buffers[cpu] -> No check Thus, to avod possible null-pointer derefernces, the related checks should be added. These results are reported by a static tool designed by myself. Link: https://lkml.kernel.org/r/20230113125501.760324-1-baijiaju1990@gmail.com Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* irqdomain: Drop bogus fwspec-mapping error handlingJohan Hovold2023-03-111-6/+1
| | | | | | | | | | | | | | | | | | | | | commit e3b7ab025e931accdc2c12acf9b75c6197f1c062 upstream. In case a newly allocated IRQ ever ends up not having any associated struct irq_data it would not even be possible to dispose the mapping. Replace the bogus disposal with a WARN_ON(). This will also be used to fix a shared-interrupt mapping race, hence the CC-stable tag. Fixes: 1e2a7d78499e ("irqdomain: Don't set type when mapping an IRQ") Cc: stable@vger.kernel.org # 4.8 Tested-by: Hsin-Yi Wang <hsinyi@chromium.org> Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230213104302.17307-4-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* irqdomain: Fix disassociation raceJohan Hovold2023-03-111-0/+5
| | | | | | | | | | | | | | | | | | | | | | commit 3f883c38f5628f46b30bccf090faec054088e262 upstream. The global irq_domain_mutex is held when mapping interrupts from non-hierarchical domains but currently not when disposing them. This specifically means that updates of the domain mapcount is racy (currently only used for statistics in debugfs). Make sure to hold the global irq_domain_mutex also when disposing mappings from non-hierarchical domains. Fixes: 9dc6be3d4193 ("genirq/irqdomain: Add map counter") Cc: stable@vger.kernel.org # 4.13 Tested-by: Hsin-Yi Wang <hsinyi@chromium.org> Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230213104302.17307-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* irqdomain: Fix association raceJohan Hovold2023-03-111-5/+14
| | | | | | | | | | | | | | | | | | | | | commit b06730a571a9ff1ba5bd6b20bf9e50e5a12f1ec6 upstream. The sanity check for an already mapped virq is done outside of the irq_domain_mutex-protected section which means that an (unlikely) racing association may not be detected. Fix this by factoring out the association implementation, which will also be used in a follow-on change to fix a shared-interrupt mapping race. Fixes: ddaf144c61da ("irqdomain: Refactor irq_domain_associate_many()") Cc: stable@vger.kernel.org # 3.11 Tested-by: Hsin-Yi Wang <hsinyi@chromium.org> Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230213104302.17307-2-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* x86/kprobes: Fix arch_check_optimized_kprobe check within optimized_kprobe rangeYang Jihong2023-03-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit f1c97a1b4ef709e3f066f82e3ba3108c3b133ae6 upstream. When arch_prepare_optimized_kprobe calculating jump destination address, it copies original instructions from jmp-optimized kprobe (see __recover_optprobed_insn), and calculated based on length of original instruction. arch_check_optimized_kprobe does not check KPROBE_FLAG_OPTIMATED when checking whether jmp-optimized kprobe exists. As a result, setup_detour_execution may jump to a range that has been overwritten by jump destination address, resulting in an inval opcode error. For example, assume that register two kprobes whose addresses are <func+9> and <func+11> in "func" function. The original code of "func" function is as follows: 0xffffffff816cb5e9 <+9>: push %r12 0xffffffff816cb5eb <+11>: xor %r12d,%r12d 0xffffffff816cb5ee <+14>: test %rdi,%rdi 0xffffffff816cb5f1 <+17>: setne %r12b 0xffffffff816cb5f5 <+21>: push %rbp 1.Register the kprobe for <func+11>, assume that is kp1, corresponding optimized_kprobe is op1. After the optimization, "func" code changes to: 0xffffffff816cc079 <+9>: push %r12 0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000 0xffffffff816cc080 <+16>: incl 0xf(%rcx) 0xffffffff816cc083 <+19>: xchg %eax,%ebp 0xffffffff816cc084 <+20>: (bad) 0xffffffff816cc085 <+21>: push %rbp Now op1->flags == KPROBE_FLAG_OPTIMATED; 2. Register the kprobe for <func+9>, assume that is kp2, corresponding optimized_kprobe is op2. register_kprobe(kp2) register_aggr_kprobe alloc_aggr_kprobe __prepare_optimized_kprobe arch_prepare_optimized_kprobe __recover_optprobed_insn // copy original bytes from kp1->optinsn.copied_insn, // jump address = <func+14> 3. disable kp1: disable_kprobe(kp1) __disable_kprobe ... if (p == orig_p || aggr_kprobe_disabled(orig_p)) { ret = disarm_kprobe(orig_p, true) // add op1 in unoptimizing_list, not unoptimized orig_p->flags |= KPROBE_FLAG_DISABLED; // op1->flags == KPROBE_FLAG_OPTIMATED | KPROBE_FLAG_DISABLED ... 4. unregister kp2 __unregister_kprobe_top ... if (!kprobe_disabled(ap) && !kprobes_all_disarmed) { optimize_kprobe(op) ... if (arch_check_optimized_kprobe(op) < 0) // because op1 has KPROBE_FLAG_DISABLED, here not return return; p->kp.flags |= KPROBE_FLAG_OPTIMIZED; // now op2 has KPROBE_FLAG_OPTIMIZED } "func" code now is: 0xffffffff816cc079 <+9>: int3 0xffffffff816cc07a <+10>: push %rsp 0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000 0xffffffff816cc080 <+16>: incl 0xf(%rcx) 0xffffffff816cc083 <+19>: xchg %eax,%ebp 0xffffffff816cc084 <+20>: (bad) 0xffffffff816cc085 <+21>: push %rbp 5. if call "func", int3 handler call setup_detour_execution: if (p->flags & KPROBE_FLAG_OPTIMIZED) { ... regs->ip = (unsigned long)op->optinsn.insn + TMPL_END_IDX; ... } The code for the destination address is 0xffffffffa021072c: push %r12 0xffffffffa021072e: xor %r12d,%r12d 0xffffffffa0210731: jmp 0xffffffff816cb5ee <func+14> However, <func+14> is not a valid start instruction address. As a result, an error occurs. Link: https://lore.kernel.org/all/20230216034247.32348-3-yangjihong1@huawei.com/ Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Cc: stable@vger.kernel.org Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* x86/kprobes: Fix __recover_optprobed_insn check optimizing logicYang Jihong2023-03-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 868a6fc0ca2407622d2833adefe1c4d284766c4c upstream. Since the following commit: commit f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") modified the update timing of the KPROBE_FLAG_OPTIMIZED, a optimized_kprobe may be in the optimizing or unoptimizing state when op.kp->flags has KPROBE_FLAG_OPTIMIZED and op->list is not empty. The __recover_optprobed_insn check logic is incorrect, a kprobe in the unoptimizing state may be incorrectly determined as unoptimizing. As a result, incorrect instructions are copied. The optprobe_queued_unopt function needs to be exported for invoking in arch directory. Link: https://lore.kernel.org/all/20230216034247.32348-2-yangjihong1@huawei.com/ Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") Cc: stable@vger.kernel.org Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* timers: Prevent union confusion from unexpected restart_syscall()Jann Horn2023-03-113-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 9f76d59173d9d146e96c66886b671c1915a5c5e5 ] The nanosleep syscalls use the restart_block mechanism, with a quirk: The `type` and `rmtp`/`compat_rmtp` fields are set up unconditionally on syscall entry, while the rest of the restart_block is only set up in the unlikely case that the syscall is actually interrupted by a signal (or pseudo-signal) that doesn't have a signal handler. If the restart_block was set up by a previous syscall (futex(..., FUTEX_WAIT, ...) or poll()) and hasn't been invalidated somehow since then, this will clobber some of the union fields used by futex_wait_restart() and do_restart_poll(). If userspace afterwards wrongly calls the restart_syscall syscall, futex_wait_restart()/do_restart_poll() will read struct fields that have been clobbered. This doesn't actually lead to anything particularly interesting because none of the union fields contain trusted kernel data, and futex(..., FUTEX_WAIT, ...) and poll() aren't syscalls where it makes much sense to apply seccomp filters to their arguments. So the current consequences are just of the "if userspace does bad stuff, it can damage itself, and that's not a problem" flavor. But still, it seems like a hazard for future developers, so invalidate the restart_block when partly setting it up in the nanosleep syscalls. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230105134403.754986-1-jannh@google.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* rcu: Suppress smp_processor_id() complaint in synchronize_rcu_expedited_wait()Paul E. McKenney2023-03-111-0/+2
| | | | | | | | | | | | | | | | | [ Upstream commit 2d7f00b2f01301d6e41fd4a28030dab0442265be ] The normal grace period's RCU CPU stall warnings are invoked from the scheduling-clock interrupt handler, and can thus invoke smp_processor_id() with impunity, which allows them to directly invoke dump_cpu_task(). In contrast, the expedited grace period's RCU CPU stall warnings are invoked from process context, which causes the dump_cpu_task() function's calls to smp_processor_id() to complain bitterly in debug kernels. This commit therefore causes synchronize_rcu_expedited_wait() to disable preemption around its call to dump_cpu_task(). Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* bpf: Fix truncation handling for mod32 dst reg wrt zeroDaniel Borkmann2023-03-111-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 9b00f1b78809309163dda2d044d9e94a3c0248a3 upstream. Recently noticed that when mod32 with a known src reg of 0 is performed, then the dst register is 32-bit truncated in verifier: 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 0: (b7) r0 = 0 1: R0_w=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0 1: (b7) r1 = -1 2: R0_w=inv0 R1_w=inv-1 R10=fp0 2: (b4) w2 = -1 3: R0_w=inv0 R1_w=inv-1 R2_w=inv4294967295 R10=fp0 3: (9c) w1 %= w0 4: R0_w=inv0 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 4: (b7) r0 = 1 5: R0_w=inv1 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 5: (1d) if r1 == r2 goto pc+1 R0_w=inv1 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 6: R0_w=inv1 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 6: (b7) r0 = 2 7: R0_w=inv2 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 7: (95) exit 7: R0=inv1 R1=inv(id=0,umin_value=4294967295,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2=inv4294967295 R10=fp0 7: (95) exit However, as a runtime result, we get 2 instead of 1, meaning the dst register does not contain (u32)-1 in this case. The reason is fairly straight forward given the 0 test leaves the dst register as-is: # ./bpftool p d x i 23 0: (b7) r0 = 0 1: (b7) r1 = -1 2: (b4) w2 = -1 3: (16) if w0 == 0x0 goto pc+1 4: (9c) w1 %= w0 5: (b7) r0 = 1 6: (1d) if r1 == r2 goto pc+1 7: (b7) r0 = 2 8: (95) exit This was originally not an issue given the dst register was marked as completely unknown (aka 64 bit unknown). However, after 468f6eafa6c4 ("bpf: fix 32-bit ALU op verification") the verifier casts the register output to 32 bit, and hence it becomes 32 bit unknown. Note that for the case where the src register is unknown, the dst register is marked 64 bit unknown. After the fix, the register is truncated by the runtime and the test passes: # ./bpftool p d x i 23 0: (b7) r0 = 0 1: (b7) r1 = -1 2: (b4) w2 = -1 3: (16) if w0 == 0x0 goto pc+2 4: (9c) w1 %= w0 5: (05) goto pc+1 6: (bc) w1 = w1 7: (b7) r0 = 1 8: (1d) if r1 == r2 goto pc+1 9: (b7) r0 = 2 10: (95) exit Semantics also match with {R,W}x mod{64,32} 0 -> {R,W}x. Invalid div has always been {R,W}x div{64,32} 0 -> 0. Rewrites are as follows: mod32: mod64: (16) if w0 == 0x0 goto pc+2 (15) if r0 == 0x0 goto pc+1 (9c) w1 %= w0 (9f) r1 %= r0 (05) goto pc+1 (bc) w1 = w1 [Salvatore Bonaccorso: This is an earlier version based on work by Daniel and John which does not rely on availability of the BPF_JMP32 instruction class. This means it is not even strictly a backport of the upstream commit mentioned but based on Daniel's and John's work to address the issue and was finalized by Thadeu Lima de Souza Cascardo.] Fixes: 468f6eafa6c4 ("bpf: fix 32-bit ALU op verification") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Edward Liaw <edliaw@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* bpf: Fix 32 bit src register truncation on div/modDaniel Borkmann2023-03-111-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit e88b2c6e5a4d9ce30d75391e4d950da74bb2bd90 upstream. While reviewing a different fix, John and I noticed an oddity in one of the BPF program dumps that stood out, for example: # bpftool p d x i 13 0: (b7) r0 = 808464450 1: (b4) w4 = 808464432 2: (bc) w0 = w0 3: (15) if r0 == 0x0 goto pc+1 4: (9c) w4 %= w0 [...] In line 2 we noticed that the mov32 would 32 bit truncate the original src register for the div/mod operation. While for the two operations the dst register is typically marked unknown e.g. from adjust_scalar_min_max_vals() the src register is not, and thus verifier keeps tracking original bounds, simplified: 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 0: (b7) r0 = -1 1: R0_w=invP-1 R1=ctx(id=0,off=0,imm=0) R10=fp0 1: (b7) r1 = -1 2: R0_w=invP-1 R1_w=invP-1 R10=fp0 2: (3c) w0 /= w1 3: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R1_w=invP-1 R10=fp0 3: (77) r1 >>= 32 4: R0_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R1_w=invP4294967295 R10=fp0 4: (bf) r0 = r1 5: R0_w=invP4294967295 R1_w=invP4294967295 R10=fp0 5: (95) exit processed 6 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0 Runtime result of r0 at exit is 0 instead of expected -1. Remove the verifier mov32 src rewrite in div/mod and replace it with a jmp32 test instead. After the fix, we result in the following code generation when having dividend r1 and divisor r6: div, 64 bit: div, 32 bit: 0: (b7) r6 = 8 0: (b7) r6 = 8 1: (b7) r1 = 8 1: (b7) r1 = 8 2: (55) if r6 != 0x0 goto pc+2 2: (56) if w6 != 0x0 goto pc+2 3: (ac) w1 ^= w1 3: (ac) w1 ^= w1 4: (05) goto pc+1 4: (05) goto pc+1 5: (3f) r1 /= r6 5: (3c) w1 /= w6 6: (b7) r0 = 0 6: (b7) r0 = 0 7: (95) exit 7: (95) exit mod, 64 bit: mod, 32 bit: 0: (b7) r6 = 8 0: (b7) r6 = 8 1: (b7) r1 = 8 1: (b7) r1 = 8 2: (15) if r6 == 0x0 goto pc+1 2: (16) if w6 == 0x0 goto pc+1 3: (9f) r1 %= r6 3: (9c) w1 %= w6 4: (b7) r0 = 0 4: (b7) r0 = 0 5: (95) exit 5: (95) exit x86 in particular can throw a 'divide error' exception for div instruction not only for divisor being zero, but also for the case when the quotient is too large for the designated register. For the edx:eax and rdx:rax dividend pair it is not an issue in x86 BPF JIT since we always zero edx (rdx). Hence really the only protection needed is against divisor being zero. [Salvatore Bonaccorso: This is an earlier version of the patch provided by Daniel Borkmann which does not rely on availability of the BPF_JMP32 instruction class. This means it is not even strictly a backport of the upstream commit mentioned but based on Daniel's and John's work to address the issue.] Fixes: 68fda450a7df ("bpf: fix 32-bit divide by zero") Co-developed-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Edward Liaw <edliaw@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* bpf: fix subprog verifier bypass by div/mod by 0 exceptionDaniel Borkmann2023-03-112-16/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit f6b1b3bf0d5f681631a293cfe1ca934b81716f1e upstream. One of the ugly leftovers from the early eBPF days is that div/mod operations based on registers have a hard-coded src_reg == 0 test in the interpreter as well as in JIT code generators that would return from the BPF program with exit code 0. This was basically adopted from cBPF interpreter for historical reasons. There are multiple reasons why this is very suboptimal and prone to bugs. To name one: the return code mapping for such abnormal program exit of 0 does not always match with a suitable program type's exit code mapping. For example, '0' in tc means action 'ok' where the packet gets passed further up the stack, which is just undesirable for such cases (e.g. when implementing policy) and also does not match with other program types. While trying to work out an exception handling scheme, I also noticed that programs crafted like the following will currently pass the verifier: 0: (bf) r6 = r1 1: (85) call pc+8 caller: R6=ctx(id=0,off=0,imm=0) R10=fp0,call_-1 callee: frame1: R1=ctx(id=0,off=0,imm=0) R10=fp0,call_1 10: (b4) (u32) r2 = (u32) 0 11: (b4) (u32) r3 = (u32) 1 12: (3c) (u32) r3 /= (u32) r2 13: (61) r0 = *(u32 *)(r1 +76) 14: (95) exit returning from callee: frame1: R0_w=pkt(id=0,off=0,r=0,imm=0) R1=ctx(id=0,off=0,imm=0) R2_w=inv0 R3_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R10=fp0,call_1 to caller at 2: R0_w=pkt(id=0,off=0,r=0,imm=0) R6=ctx(id=0,off=0,imm=0) R10=fp0,call_-1 from 14 to 2: R0=pkt(id=0,off=0,r=0,imm=0) R6=ctx(id=0,off=0,imm=0) R10=fp0,call_-1 2: (bf) r1 = r6 3: (61) r1 = *(u32 *)(r1 +80) 4: (bf) r2 = r0 5: (07) r2 += 8 6: (2d) if r2 > r1 goto pc+1 R0=pkt(id=0,off=0,r=8,imm=0) R1=pkt_end(id=0,off=0,imm=0) R2=pkt(id=0,off=8,r=8,imm=0) R6=ctx(id=0,off=0,imm=0) R10=fp0,call_-1 7: (71) r0 = *(u8 *)(r0 +0) 8: (b7) r0 = 1 9: (95) exit from 6 to 8: safe processed 16 insns (limit 131072), stack depth 0+0 Basically what happens is that in the subprog we make use of a div/mod by 0 exception and in the 'normal' subprog's exit path we just return skb->data back to the main prog. This has the implication that the verifier thinks we always get a pkt pointer in R0 while we still have the implicit 'return 0' from the div as an alternative unconditional return path earlier. Thus, R0 then contains 0, meaning back in the parent prog we get the address range of [0x0, skb->data_end] as read and writeable. Similar can be crafted with other pointer register types. Since i) BPF_ABS/IND is not allowed in programs that contain BPF to BPF calls (and generally it's also disadvised to use in native eBPF context), ii) unknown opcodes don't return zero anymore, iii) we don't return an exception code in dead branches, the only last missing case affected and to fix is the div/mod handling. What we would really need is some infrastructure to propagate exceptions all the way to the original prog unwinding the current stack and returning that code to the caller of the BPF program. In user space such exception handling for similar runtimes is typically implemented with setjmp(3) and longjmp(3) as one possibility which is not available in the kernel, though (kgdb used to implement it in kernel long time ago). I implemented a PoC exception handling mechanism into the BPF interpreter with porting setjmp()/longjmp() into x86_64 and adding a new internal BPF_ABRT opcode that can use a program specific exception code for all exception cases we have (e.g. div/mod by 0, unknown opcodes, etc). While this seems to work in the constrained BPF environment (meaning, here, we don't need to deal with state e.g. from memory allocations that we would need to undo before going into exception state), it still has various drawbacks: i) we would need to implement the setjmp()/longjmp() for every arch supported in the kernel and for x86_64, arm64, sparc64 JITs currently supporting calls, ii) it has unconditional additional cost on main program entry to store CPU register state in initial setjmp() call, and we would need some way to pass the jmp_buf down into ___bpf_prog_run() for main prog and all subprogs, but also storing on stack is not really nice (other option would be per-cpu storage for this, but it also has the drawback that we need to disable preemption for every BPF program types). All in all this approach would add a lot of complexity. Another poor-man's solution would be to have some sort of additional shared register or scratch buffer to hold state for exceptions, and test that after every call return to chain returns and pass R0 all the way down to BPF prog caller. This is also problematic in various ways: i) an additional register doesn't map well into JITs, and some other scratch space could only be on per-cpu storage, which, again has the side-effect that this only works when we disable preemption, or somewhere in the input context which is not available everywhere either, and ii) this adds significant runtime overhead by putting conditionals after each and every call, as well as implementation complexity. Yet another option is to teach verifier that div/mod can return an integer, which however is also complex to implement as verifier would need to walk such fake 'mov r0,<code>; exit;' sequeuence and there would still be no guarantee for having propagation of this further down to the BPF caller as proper exception code. For parent prog, it is also is not distinguishable from a normal return of a constant scalar value. The approach taken here is a completely different one with little complexity and no additional overhead involved in that we make use of the fact that a div/mod by 0 is undefined behavior. Instead of bailing out, we adapt the same behavior as on some major archs like ARMv8 [0] into eBPF as well: X div 0 results in 0, and X mod 0 results in X. aarch64 and aarch32 ISA do not generate any traps or otherwise aborts of program execution for unsigned divides. I verified this also with a test program compiled by gcc and clang, and the behavior matches with the spec. Going forward we adapt the eBPF verifier to emit such rewrites once div/mod by register was seen. cBPF is not touched and will keep existing 'return 0' semantics. Given the options, it seems the most suitable from all of them, also since major archs have similar schemes in place. Given this is all in the realm of undefined behavior, we still have the option to adapt if deemed necessary and this way we would also have the option of more flexibility from LLVM code generation side (which is then fully visible to verifier). Thus, this patch i) fixes the panic seen in above program and ii) doesn't bypass the verifier observations. [0] ARM Architecture Reference Manual, ARMv8 [ARM DDI 0487B.b] http://infocenter.arm.com/help/topic/com.arm.doc.ddi0487b.b/DDI0487B_b_armv8_arm.pdf 1) aarch64 instruction set: section C3.4.7 and C6.2.279 (UDIV) "A division by zero results in a zero being written to the destination register, without any indication that the division by zero occurred." 2) aarch32 instruction set: section F1.4.8 and F5.1.263 (UDIV) "For the SDIV and UDIV instructions, division by zero always returns a zero result." Fixes: f4d7e40a5b71 ("bpf: introduce function calls (verification)") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Edward Liaw <edliaw@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* bpf: Do not use ax register in interpreter on div/modDaniel Borkmann2023-03-111-17/+14
| | | | | | | | | | | | | | | | | | | | | Commit c348d806ed1d3075af52345344243824d72c4945 upstream. Partially undo old commit 144cd91c4c2b ("bpf: move tmp variable into ax register in interpreter"). The reason we need this here is because ax register will be used for holding temporary state for div/mod instruction which otherwise interpreter would corrupt. This will cause a small +8 byte stack increase for interpreter, but with the gain that we can use it from verifier rewrites as scratch register. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: John Fastabend <john.fastabend@gmail.com> [cascardo: This partial revert is needed in order to support using AX for the following two commits, as there is no JMP32 on 4.19.y] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> [edliaw: Removed redeclaration of tmp introduced by patch differences between 4.14 and 4.19] Signed-off-by: Edward Liaw <edliaw@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* alarmtimer: Prevent starvation by small intervals and SIG_IGNThomas Gleixner2023-02-251-4/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d125d1349abeb46945dc5e98f7824bf688266f13 upstream. syzbot reported a RCU stall which is caused by setting up an alarmtimer with a very small interval and ignoring the signal. The reproducer arms the alarm timer with a relative expiry of 8ns and an interval of 9ns. Not a problem per se, but that's an issue when the signal is ignored because then the timer is immediately rearmed because there is no way to delay that rearming to the signal delivery path. See posix_timer_fn() and commit 58229a189942 ("posix-timers: Prevent softirq starvation by small intervals and SIG_IGN") for details. The reproducer does not set SIG_IGN explicitely, but it sets up the timers signal with SIGCONT. That has the same effect as explicitely setting SIG_IGN for a signal as SIGCONT is ignored if there is no handler set and the task is not ptraced. The log clearly shows that: [pid 5102] --- SIGCONT {si_signo=SIGCONT, si_code=SI_TIMER, si_timerid=0, si_overrun=316014, si_int=0, si_ptr=NULL} --- It works because the tasks are traced and therefore the signal is queued so the tracer can see it, which delays the restart of the timer to the signal delivery path. But then the tracer is killed: [pid 5087] kill(-5102, SIGKILL <unfinished ...> ... ./strace-static-x86_64: Process 5107 detached and after it's gone the stall can be observed: syzkaller login: [ 79.439102][ C0] hrtimer: interrupt took 68471 ns [ 184.460538][ C1] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: ... [ 184.658237][ C1] rcu: Stack dump where RCU GP kthread last ran: [ 184.664574][ C1] Sending NMI from CPU 1 to CPUs 0: [ 184.669821][ C0] NMI backtrace for cpu 0 [ 184.669831][ C0] CPU: 0 PID: 5108 Comm: syz-executor192 Not tainted 6.2.0-rc6-next-20230203-syzkaller #0 ... [ 184.670036][ C0] Call Trace: [ 184.670041][ C0] <IRQ> [ 184.670045][ C0] alarmtimer_fired+0x327/0x670 posix_timer_fn() prevents that by checking whether the interval for timers which have the signal ignored is smaller than a jiffie and artifically delay it by shifting the next expiry out by a jiffie. That's accurate vs. the overrun accounting, but slightly inaccurate vs. timer_gettimer(2). The comment in that function says what needs to be done and there was a fix available for the regular userspace induced SIG_IGN mechanism, but that did not work due to the implicit ignore for SIGCONT and similar signals. This needs to be worked on, but for now the only available workaround is to do exactly what posix_timer_fn() does: Increase the interval of self-rearming timers, which have their signal ignored, to at least a jiffie. Interestingly this has been fixed before via commit ff86bf0c65f1 ("alarmtimer: Rate limit periodic intervals") already, but that fix got lost in a later rework. Reported-by: syzbot+b9564ba6e8e00694511b@syzkaller.appspotmail.com Fixes: f2c45807d399 ("alarmtimer: Switch over to generic set/get/rearm routine") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <jstultz@google.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/87k00q1no2.ffs@tglx Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* exit: Use READ_ONCE() for all oops/warn limit readsKees Cook2023-02-062-4/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 7535b832c6399b5ebfc5b53af5c51dd915ee2538 upstream. Use a temporary variable to take full advantage of READ_ONCE() behavior. Without this, the report (and even the test) might be out of sync with the initial test. Reported-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/lkml/Y5x7GXeluFmZ8E0E@hirez.programming.kicks-ass.net Fixes: 9fc9e278a5c0 ("panic: Introduce warn_limit") Fixes: d4ccd54d28d3 ("exit: Put an upper limit on how often we can oops") Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jann Horn <jannh@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Petr Mladek <pmladek@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Marco Elver <elver@google.com> Cc: tangmeng <tangmeng@uniontech.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* panic: Expose "warn_count" to sysfsKees Cook2023-02-061-2/+20
| | | | | | | | | | | | | | | | | | | commit 8b05aa26336113c4cea25f1c333ee8cd4fc212a6 upstream. Since Warn count is now tracked and is a fairly interesting signal, add the entry /sys/kernel/warn_count to expose it to userspace. Cc: Petr Mladek <pmladek@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: tangmeng <tangmeng@uniontech.com> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-6-keescook@chromium.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* panic: Introduce warn_limitKees Cook2023-02-061-0/+27
| | | | | | | | | | | | | | | | | | | | | | | | | commit 9fc9e278a5c0b708eeffaf47d6eb0c82aa74ed78 upstream. Like oops_limit, add warn_limit for limiting the number of warnings when panic_on_warn is not set. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Petr Mladek <pmladek@suse.com> Cc: tangmeng <tangmeng@uniontech.com> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-doc@vger.kernel.org Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-5-keescook@chromium.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* panic: Consolidate open-coded panic_on_warn checksKees Cook2023-02-062-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 79cc1ba7badf9e7a12af99695a557e9ce27ee967 upstream. Several run-time checkers (KASAN, UBSAN, KFENCE, KCSAN, sched) roll their own warnings, and each check "panic_on_warn". Consolidate this into a single function so that future instrumentation can be added in a single location. Cc: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Gow <davidgow@google.com> Cc: tangmeng <tangmeng@uniontech.com> Cc: Jann Horn <jannh@google.com> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Petr Mladek <pmladek@suse.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: kasan-dev@googlegroups.com Cc: linux-mm@kvack.org Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Link: https://lore.kernel.org/r/20221117234328.594699-4-keescook@chromium.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* exit: Allow oops_limit to be disabledKees Cook2023-02-061-1/+1
| | | | | | | | | | | | | | | | | | | | | commit de92f65719cd672f4b48397540b9f9eff67eca40 upstream. In preparation for keeping oops_limit logic in sync with warn_limit, have oops_limit == 0 disable checking the Oops counter. Cc: Jann Horn <jannh@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Huang Ying <ying.huang@intel.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-doc@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* exit: Expose "oops_count" to sysfsKees Cook2023-02-061-2/+20
| | | | | | | | | | | | | | | | commit 9db89b41117024f80b38b15954017fb293133364 upstream. Since Oops count is now tracked and is a fairly interesting signal, add the entry /sys/kernel/oops_count to expose it to userspace. Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jann Horn <jannh@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-3-keescook@chromium.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* exit: Put an upper limit on how often we can oopsJann Horn2023-02-061-0/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d4ccd54d28d3c8598e2354acc13e28c060961dbb upstream. Many Linux systems are configured to not panic on oops; but allowing an attacker to oops the system **really** often can make even bugs that look completely unexploitable exploitable (like NULL dereferences and such) if each crash elevates a refcount by one or a lock is taken in read mode, and this causes a counter to eventually overflow. The most interesting counters for this are 32 bits wide (like open-coded refcounts that don't use refcount_t). (The ldsem reader count on 32-bit platforms is just 16 bits, but probably nobody cares about 32-bit platforms that much nowadays.) So let's panic the system if the kernel is constantly oopsing. The speed of oopsing 2^32 times probably depends on several factors, like how long the stack trace is and which unwinder you're using; an empirically important one is whether your console is showing a graphical environment or a text console that oopses will be printed to. In a quick single-threaded benchmark, it looks like oopsing in a vfork() child with a very short stack trace only takes ~510 microseconds per run when a graphical console is active; but switching to a text console that oopses are printed to slows it down around 87x, to ~45 milliseconds per run. (Adding more threads makes this faster, but the actual oops printing happens under &die_lock on x86, so you can maybe speed this up by a factor of around 2 and then any further improvement gets eaten up by lock contention.) It looks like it would take around 8-12 days to overflow a 32-bit counter with repeated oopsing on a multi-core X86 system running a graphical environment; both me (in an X86 VM) and Seth (with a distro kernel on normal hardware in a standard configuration) got numbers in that ballpark. 12 days aren't *that* short on a desktop system, and you'd likely need much longer on a typical server system (assuming that people don't run graphical desktop environments on their servers), and this is a *very* noisy and violent approach to exploiting the kernel; and it also seems to take orders of magnitude longer on some machines, probably because stuff like EFI pstore will slow it down a ton if that's active. Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20221107201317.324457-1-jannh@google.com Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-2-keescook@chromium.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* exit: Add and use make_task_dead.Eric W. Biederman2023-02-061-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream. There are two big uses of do_exit. The first is it's design use to be the guts of the exit(2) system call. The second use is to terminate a task after something catastrophic has happened like a NULL pointer in kernel code. Add a function make_task_dead that is initialy exactly the same as do_exit to cover the cases where do_exit is called to handle catastrophic failure. In time this can probably be reduced to just a light wrapper around do_task_dead. For now keep it exactly the same so that there will be no behavioral differences introducing this new concept. Replace all of the uses of do_exit that use it for catastraphic task cleanup with make_task_dead to make it clear what the code is doing. As part of this rename rewind_stack_do_exit rewind_stack_and_make_dead. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* panic: unset panic_on_warn inside panic()Tiezhu Yang2023-02-061-9/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1a2383e8b84c0451fd9b1eec3b9aab16f30b597c upstream. In the current code, the following three places need to unset panic_on_warn before calling panic() to avoid recursive panics: kernel/kcsan/report.c: print_report() kernel/sched/core.c: __schedule_bug() mm/kfence/report.c: kfence_report_error() In order to avoid copy-pasting "panic_on_warn = 0" all over the places, it is better to move it inside panic() and then remove it from the other places. Link: https://lkml.kernel.org/r/1644324666-15947-4-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Reviewed-by: Marco Elver <elver@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Xuefeng Li <lixuefeng@loongson.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Make sure trace_printk() can output as soon as it can be usedSteven Rostedt (Google)2023-02-063-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 3bb06eb6e9acf7c4a3e1b5bc87aed398ff8e2253 upstream. Currently trace_printk() can be used as soon as early_trace_init() is called from start_kernel(). But if a crash happens, and "ftrace_dump_on_oops" is set on the kernel command line, all you get will be: [ 0.456075] <idle>-0 0dN.2. 347519us : Unknown type 6 [ 0.456075] <idle>-0 0dN.2. 353141us : Unknown type 6 [ 0.456075] <idle>-0 0dN.2. 358684us : Unknown type 6 This is because the trace_printk() event (type 6) hasn't been registered yet. That gets done via an early_initcall(), which may be early, but not early enough. Instead of registering the trace_printk() event (and other ftrace events, which are not trace events) via an early_initcall(), have them registered at the same time that trace_printk() can be used. This way, if there is a crash before early_initcall(), then the trace_printk()s will actually be useful. Link: https://lkml.kernel.org/r/20230104161412.019f6c55@gandalf.local.home Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: e725c731e3bb1 ("tracing: Split tracing initialization into two for early initialization") Reported-by: "Joel Fernandes (Google)" <joel@joelfernandes.org> Tested-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* module: Don't wait for GOING modulesPetr Pavlu2023-02-061-5/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 0254127ab977e70798707a7a2b757c9f3c971210 upstream. During a system boot, it can happen that the kernel receives a burst of requests to insert the same module but loading it eventually fails during its init call. For instance, udev can make a request to insert a frequency module for each individual CPU when another frequency module is already loaded which causes the init function of the new module to return an error. Since commit 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading"), the kernel waits for modules in MODULE_STATE_GOING state to finish unloading before making another attempt to load the same module. This creates unnecessary work in the described scenario and delays the boot. In the worst case, it can prevent udev from loading drivers for other devices and might cause timeouts of services waiting on them and subsequently a failed boot. This patch attempts a different solution for the problem 6e6de3dee51a was trying to solve. Rather than waiting for the unloading to complete, it returns a different error code (-EBUSY) for modules in the GOING state. This should avoid the error situation that was described in 6e6de3dee51a (user space attempting to load a dependent module because the -EEXIST error code would suggest to user space that the first module had been loaded successfully), while avoiding the delay situation too. This has been tested on linux-next since December 2022 and passes all kmod selftests except test 0009 with module compression enabled but it has been confirmed that this issue has existed and has gone unnoticed since prior to this commit and can also be reproduced without module compression with a simple usleep(5000000) on tools/modprobe.c [0]. These failures are caused by hitting the kernel mod_concurrent_max and can happen either due to a self inflicted kernel module auto-loead DoS somehow or on a system with large CPU count and each CPU count incorrectly triggering many module auto-loads. Both of those issues need to be fixed in-kernel. [0] https://lore.kernel.org/all/Y9A4fiobL6IHp%2F%2FP@bombadil.infradead.org/ Fixes: 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading") Co-developed-by: Martin Wilck <mwilck@suse.com> Signed-off-by: Martin Wilck <mwilck@suse.com> Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Cc: stable@vger.kernel.org Reviewed-by: Petr Mladek <pmladek@suse.com> [mcgrof: enhance commit log with testing and kmod test result interpretation ] Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* prlimit: do_prlimit needs to have a speculation checkGreg Kroah-Hartman2023-01-241-0/+2
| | | | | | | | | | | | | | commit 739790605705ddcf18f21782b9c99ad7d53a8c11 upstream. do_prlimit() adds the user-controlled resource value to a pointer that will subsequently be dereferenced. In order to help prevent this codepath from being used as a spectre "gadget" a barrier needs to be added after checking the range. Reported-by: Jordy Zomer <jordyzomer@google.com> Tested-by: Jordy Zomer <jordyzomer@google.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Fix infinite loop in tracing_read_pipe on overflowed print_trace_lineYang Jihong2023-01-181-1/+14
| | | | | | | | | | | | | | | | commit c1ac03af6ed45d05786c219d102f37eb44880f28 upstream. print_trace_line may overflow seq_file buffer. If the event is not consumed, the while loop keeps peeking this event, causing a infinite loop. Link: https://lkml.kernel.org/r/20221129113009.182425-1-yangjihong1@huawei.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: stable@vger.kernel.org Fixes: 088b1e427dbba ("ftrace: pipe fixes") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* gcov: add support for checksum fieldRickard x Andersson2023-01-181-0/+5
| | | | | | | | | | | | | | | | | | | | commit e96b95c2b7a63a454b6498e2df67aac14d046d13 upstream. In GCC version 12.1 a checksum field was added. This patch fixes a kernel crash occurring during boot when using gcov-kernel with GCC version 12.2. The crash occurred on a system running on i.MX6SX. Link: https://lkml.kernel.org/r/20221220102318.3418501-1-rickaran@axis.com Fixes: 977ef30a7d88 ("gcov: support GCC 12.1 and newer compilers") Signed-off-by: Rickard x Andersson <rickaran@axis.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Tested-by: Peter Oberparleiter <oberpar@linux.ibm.com> Reviewed-by: Martin Liska <mliska@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* acct: fix potential integer overflow in encode_comp_t()Zheng Yejian2023-01-181-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit c5f31c655bcc01b6da53b836ac951c1556245305 ] The integer overflow is descripted with following codes: > 317 static comp_t encode_comp_t(u64 value) > 318 { > 319 int exp, rnd; ...... > 341 exp <<= MANTSIZE; > 342 exp += value; > 343 return exp; > 344 } Currently comp_t is defined as type of '__u16', but the variable 'exp' is type of 'int', so overflow would happen when variable 'exp' in line 343 is greater than 65535. Link: https://lkml.kernel.org/r/20210515140631.369106-3-zhengyejian1@huawei.com Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zhang Jinhao <zhangjinhao2@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* blktrace: Fix output non-blktrace event when blk_classic option enabledYang Jihong2023-01-181-1/+2
| | | | | | | | | | | | | | | | | | | | | [ Upstream commit f596da3efaf4130ff61cd029558845808df9bf99 ] When the blk_classic option is enabled, non-blktrace events must be filtered out. Otherwise, events of other types are output in the blktrace classic format, which is unexpected. The problem can be triggered in the following ways: # echo 1 > /sys/kernel/debug/tracing/options/blk_classic # echo 1 > /sys/kernel/debug/tracing/events/enable # echo blk > /sys/kernel/debug/tracing/current_tracer # cat /sys/kernel/debug/tracing/trace_pipe Fixes: c71a89615411 ("blktrace: add ftrace plugin") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Link: https://lore.kernel.org/r/20221122040410.85113-1-yangjihong1@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* perf: Fix possible memleak in pmu_dev_alloc()Chen Zhongjin2023-01-181-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit e8d7a90c08ce963c592fb49845f2ccc606a2ac21 ] In pmu_dev_alloc(), when dev_set_name() failed, it will goto free_dev and call put_device(pmu->dev) to release it. However pmu->dev->release is assigned after this, which makes warning and memleak. Call dev_set_name() after pmu->dev->release = pmu_dev_release to fix it. Device '(null)' does not have a release() function... WARNING: CPU: 2 PID: 441 at drivers/base/core.c:2332 device_release+0x1b9/0x240 ... Call Trace: <TASK> kobject_put+0x17f/0x460 put_device+0x20/0x30 pmu_dev_alloc+0x152/0x400 perf_pmu_register+0x96b/0xee0 ... kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak) unreferenced object 0xffff888014759000 (size 2048): comm "modprobe", pid 441, jiffies 4294931444 (age 38.332s) backtrace: [<0000000005aed3b4>] kmalloc_trace+0x27/0x110 [<000000006b38f9b8>] pmu_dev_alloc+0x50/0x400 [<00000000735f17be>] perf_pmu_register+0x96b/0xee0 [<00000000e38477f1>] 0xffffffffc0ad8603 [<000000004e162216>] do_one_initcall+0xd0/0x4e0 ... Fixes: abe43400579d ("perf: Sysfs enumeration") Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20221111103653.91058-1-chenzhongjin@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* PM: hibernate: Fix mistake in kerneldoc commentxiongxin2023-01-181-2/+2
| | | | | | | | | | | | | | | | | | | [ Upstream commit 6e5d7300cbe7c3541bc31f16db3e9266e6027b4b ] The actual maximum image size formula in hibernate_preallocate_memory() is as follows: max_size = (count - (size + PAGES_FOR_IO)) / 2 - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE); but the one in the kerneldoc comment of the function is different and incorrect. Fixes: ddeb64870810 ("PM / Hibernate: Add sysfs knob to control size of memory for drivers") Signed-off-by: xiongxin <xiongxin@kylinos.cn> [ rjw: Subject and changelog rewrite ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* memcg: fix possible use-after-free in memcg_write_event_control()Tejun Heo2022-12-141-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4a7ba45b1a435e7097ca0f79a847d0949d0eb088 upstream. memcg_write_event_control() accesses the dentry->d_name of the specified control fd to route the write call. As a cgroup interface file can't be renamed, it's safe to access d_name as long as the specified file is a regular cgroup file. Also, as these cgroup interface files can't be removed before the directory, it's safe to access the parent too. Prior to 347c4a874710 ("memcg: remove cgroup_event->cft"), there was a call to __file_cft() which verified that the specified file is a regular cgroupfs file before further accesses. The cftype pointer returned from __file_cft() was no longer necessary and the commit inadvertently dropped the file type check with it allowing any file to slip through. With the invarients broken, the d_name and parent accesses can now race against renames and removals of arbitrary files and cause use-after-free's. Fix the bug by resurrecting the file type check in __file_cft(). Now that cgroupfs is implemented through kernfs, checking the file operations needs to go through a layer of indirection. Instead, let's check the superblock and dentry type. Link: https://lkml.kernel.org/r/Y5FRm/cfcKPGzWwl@slm.duckdns.org Fixes: 347c4a874710 ("memcg: remove cgroup_event->cft") Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jann Horn <jannh@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: <stable@vger.kernel.org> [3.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* proc: proc_skip_spaces() shouldn't think it is working on C stringsLinus Torvalds2022-12-081-12/+13
| | | | | | | | | | | | | | | | | | | | | commit bce9332220bd677d83b19d21502776ad555a0e73 upstream. proc_skip_spaces() seems to think it is working on C strings, and ends up being just a wrapper around skip_spaces() with a really odd calling convention. Instead of basing it on skip_spaces(), it should have looked more like proc_skip_char(), which really is the exact same function (except it skips a particular character, rather than whitespace). So use that as inspiration, odd coding and all. Now the calling convention actually makes sense and works for the intended purpose. Reported-and-tested-by: Kyle Zeng <zengyhkyle@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* proc: avoid integer type confusion in get_proc_longLinus Torvalds2022-12-081-3/+2
| | | | | | | | | | | | | | commit e6cfaf34be9fcd1a8285a294e18986bfc41a409c upstream. proc_get_long() is passed a size_t, but then assigns it to an 'int' variable for the length. Let's not do that, even if our IO paths are limited to MAX_RW_COUNT (exactly because of these kinds of type errors). So do the proper test in the rigth type. Reported-by: Kyle Zeng <zengyhkyle@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* perf: Add sample_flags to indicate the PMU-filled sample dataKan Liang2022-12-081-6/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 3aac580d5cc3001ca1627725b3b61edb529f341d ] On some platforms, some data e.g., timestamps, can be retrieved from the PMU driver. Usually, the data from the PMU driver is more accurate. The current perf kernel should output the PMU-filled sample data if it's available. To check the availability of the PMU-filled sample data, the current perf kernel initializes the related fields in the perf_sample_data_init(). When outputting a sample, the perf checks whether the field is updated by the PMU driver. If yes, the updated value will be output. If not, the perf uses an SW way to calculate the value or just outputs the initialized value if an SW way is unavailable either. With more and more data being provided by the PMU driver, more fields has to be initialized in the perf_sample_data_init(). That will increase the number of cache lines touched in perf_sample_data_init() and be harmful to the performance. Add new "sample_flags" to indicate the PMU-filled sample data. The PMU driver should set the corresponding PERF_SAMPLE_ flag when the field is updated. The initialization of the corresponding field is not required anymore. The following patches will make use of it and remove the corresponding fields from the perf_sample_data_init(), which will further minimize the number of cache lines touched. Only clear the sample flags that have already been done by the PMU driver in the perf_prepare_sample() for the PERF_RECORD_SAMPLE. For the other PERF_RECORD_ event type, the sample data is not available. Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220901130959.1285717-2-kan.liang@linux.intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* ring_buffer: Do not deactivate non-existant pagesDaniil Tatianin2022-11-251-2/+2
| | | | | | | | | | | | | | | | | | commit 56f4ca0a79a9f1af98f26c54b9b89ba1f9bcc6bd upstream. rb_head_page_deactivate() expects cpu_buffer to contain a valid list of ->pages, so verify that the list is actually present before calling it. Found by Linux Verification Center (linuxtesting.org) with the SVACE static analysis tool. Link: https://lkml.kernel.org/r/20221114143129.3534443-1-d-tatianin@yandex-team.ru Cc: stable@vger.kernel.org Fixes: 77ae365eca895 ("ring-buffer: make lockless") Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ftrace: Fix null pointer dereference in ftrace_add_mod()Xiu Jianfeng2022-11-251-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 19ba6c8af9382c4c05dc6a0a79af3013b9a35cd0 upstream. The @ftrace_mod is allocated by kzalloc(), so both the members {prev,next} of @ftrace_mode->list are NULL, it's not a valid state to call list_del(). If kstrdup() for @ftrace_mod->{func|module} fails, it goes to @out_free tag and calls free_ftrace_mod() to destroy @ftrace_mod, then list_del() will write prev->next and next->prev, where null pointer dereference happens. BUG: kernel NULL pointer dereference, address: 0000000000000008 Oops: 0002 [#1] PREEMPT SMP NOPTI Call Trace: <TASK> ftrace_mod_callback+0x20d/0x220 ? do_filp_open+0xd9/0x140 ftrace_process_regex.isra.51+0xbf/0x130 ftrace_regex_write.isra.52.part.53+0x6e/0x90 vfs_write+0xee/0x3a0 ? __audit_filter_op+0xb1/0x100 ? auditd_test_task+0x38/0x50 ksys_write+0xa5/0xe0 do_syscall_64+0x3a/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Kernel panic - not syncing: Fatal exception So call INIT_LIST_HEAD() to initialize the list member to fix this issue. Link: https://lkml.kernel.org/r/20221116015207.30858-1-xiujianfeng@huawei.com Cc: stable@vger.kernel.org Fixes: 673feb9d76ab ("ftrace: Add :mod: caching infrastructure to trace_array") Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ftrace: Optimize the allocation for mcount entriesWang Wensheng2022-11-251-1/+1
| | | | | | | | | | | | | | | | | commit bcea02b096333dc74af987cb9685a4dbdd820840 upstream. If we can't allocate this size, try something smaller with half of the size. Its order should be decreased by one instead of divided by two. Link: https://lkml.kernel.org/r/20221109094434.84046-3-wangwensheng4@huawei.com Cc: <mhiramat@kernel.org> Cc: <mark.rutland@arm.com> Cc: stable@vger.kernel.org Fixes: a79008755497d ("ftrace: Allocate the mcount record pages as groups") Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ftrace: Fix the possible incorrect kernel messageWang Wensheng2022-11-251-1/+1
| | | | | | | | | | | | | | | | | commit 08948caebe93482db1adfd2154eba124f66d161d upstream. If the number of mcount entries is an integer multiple of ENTRIES_PER_PAGE, the page count showing on the console would be wrong. Link: https://lkml.kernel.org/r/20221109094434.84046-2-wangwensheng4@huawei.com Cc: <mhiramat@kernel.org> Cc: <mark.rutland@arm.com> Cc: stable@vger.kernel.org Fixes: 5821e1b74f0d0 ("function tracing: fix wrong pos computing when read buffer has been fulfilled") Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-22 07:45:33 +0000