summaryrefslogtreecommitdiffstats
path: root/kernel
Commit message (Collapse)AuthorAgeFilesLines
* tracing/kprobes: Do the notrace functions check without kprobes on ftraceMasami Hiramatsu2021-01-192-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | commit 7bb83f6fc4ee84e95d0ac0d14452c2619fb3fe70 upstream. Enable the notrace function check on the architecture which doesn't support kprobes on ftrace but support dynamic ftrace. This notrace function check is not only for the kprobes on ftrace but also sw-breakpoint based kprobes. Thus there is no reason to limit this check for the arch which supports kprobes on ftrace. This also changes the dependency of Kconfig. Because kprobe event uses the function tracer's address list for identifying notrace function, if the CONFIG_DYNAMIC_FTRACE=n, it can not check whether the target function is notrace or not. Link: https://lkml.kernel.org/r/20210105065730.2634785-1-naveen.n.rao@linux.vnet.ibm.com Link: https://lkml.kernel.org/r/161007957862.114704.4512260007555399463.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 45408c4f92506 ("tracing: kprobes: Prohibit probing on notrace function") Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* workqueue: Kick a worker based on the actual activation of delayed worksYunfeng Ye2021-01-121-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 01341fbd0d8d4e717fc1231cdffe00343088ce0b ] In realtime scenario, We do not want to have interference on the isolated cpu cores. but when invoking alloc_workqueue() for percpu wq on the housekeeping cpu, it kick a kworker on the isolated cpu. alloc_workqueue pwq_adjust_max_active wake_up_worker The comment in pwq_adjust_max_active() said: "Need to kick a worker after thawed or an unbound wq's max_active is bumped" So it is unnecessary to kick a kworker for percpu's wq when invoking alloc_workqueue(). this patch only kick a worker based on the actual activation of delayed works. Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* module: delay kobject uevent until after module init callJessica Yu2021-01-061-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 38dc717e97153e46375ee21797aa54777e5498f3 ] Apparently there has been a longstanding race between udev/systemd and the module loader. Currently, the module loader sends a uevent right after sysfs initialization, but before the module calls its init function. However, some udev rules expect that the module has initialized already upon receiving the uevent. This race has been triggered recently (see link in references) in some systemd mount unit files. For instance, the configfs module creates the /sys/kernel/config mount point in its init function, however the module loader issues the uevent before this happens. sys-kernel-config.mount expects to be able to mount /sys/kernel/config upon receipt of the module loading uevent, but if the configfs module has not called its init function yet, then this directory will not exist and the mount unit fails. A similar situation exists for sys-fs-fuse-connections.mount, as the fuse sysfs mount point is created during the fuse module's init function. If udev is faster than module initialization then the mount unit would fail in a similar fashion. To fix this race, delay the module KOBJ_ADD uevent until after the module has finished calling its init routine. References: https://github.com/systemd/systemd/issues/17586 Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Tested-By: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com> Signed-off-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* module: set MODULE_STATE_GOING state when a module fails to loadMiroslav Benes2021-01-061-0/+1
| | | | | | | | | | | | | [ Upstream commit 5e8ed280dab9eeabc1ba0b2db5dbe9fe6debb6b5 ] If a module fails to load due to an error in prepare_coming_module(), the following error handling in load_module() runs with MODULE_STATE_COMING in module's state. Fix it by correctly setting MODULE_STATE_GOING under "bug_cleanup" label. Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* genirq/irqdomain: Don't try to free an interrupt that has no mappingMarc Zyngier2020-12-301-2/+9
| | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 4615fbc3788ddc8e7c6d697714ad35a53729aa2c ] When an interrupt allocation fails for N interrupts, it is pretty common for the error handling code to free the same number of interrupts, no matter how many interrupts have actually been allocated. This may result in the domain freeing code to be unexpectedly called for interrupts that have no mapping in that domain. Things end pretty badly. Instead, add some checks to irq_domain_free_irqs_hierarchy() to make sure that thiss does not follow the hierarchy if no mapping exists for a given interrupt. Fixes: 6a6544e520abe ("genirq/irqdomain: Remove auto-recursive hierarchy support") Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201129135551.396777-1-maz@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
* sched: Reenable interrupts in do_sched_yield()Thomas Gleixner2020-12-301-5/+1
| | | | | | | | | | | | | | | | [ Upstream commit 345a957fcc95630bf5535d7668a59ed983eb49a7 ] do_sched_yield() invokes schedule() with interrupts disabled which is not allowed. This goes back to the pre git era to commit a6efb709806c ("[PATCH] irqlock patch 2.5.27-H6") in the history tree. Reenable interrupts and remove the misleading comment which "explains" it. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/87r1pt7y5c.fsf@nanos.tec.linutronix.de Signed-off-by: Sasha Levin <sashal@kernel.org>
* sched/deadline: Fix sched_dl_global_validate()Peng Liu2020-12-302-26/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit a57415f5d1e43c3a5c5d412cd85e2792d7ed9b11 ] When change sched_rt_{runtime, period}_us, we validate that the new settings should at least accommodate the currently allocated -dl bandwidth: sched_rt_handler() --> sched_dl_bandwidth_validate() { new_bw = global_rt_runtime()/global_rt_period(); for_each_possible_cpu(cpu) { dl_b = dl_bw_of(cpu); if (new_bw < dl_b->total_bw) <------- ret = -EBUSY; } } But under CONFIG_SMP, dl_bw is per root domain , but not per CPU, dl_b->total_bw is the allocated bandwidth of the whole root domain. Instead, we should compare dl_b->total_bw against "cpus*new_bw", where 'cpus' is the number of CPUs of the root domain. Also, below annotation(in kernel/sched/sched.h) implied implementation only appeared in SCHED_DEADLINE v2[1], then deadline scheduler kept evolving till got merged(v9), but the annotation remains unchanged, meaningless and misleading, update it. * With respect to SMP, the bandwidth is given on a per-CPU basis, * meaning that: * - dl_bw (< 100%) is the bandwidth of the system (group) on each CPU; * - dl_total_bw array contains, in the i-eth element, the currently * allocated bandwidth on the i-eth CPU. [1]: https://lore.kernel.org/lkml/1267385230.13676.101.camel@Palantir/ Fixes: 332ac17ef5bf ("sched/deadline: Add bandwidth management for SCHED_DEADLINE tasks") Signed-off-by: Peng Liu <iwtbavbm@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Juri Lelli <juri.lelli@redhat.com> Link: https://lkml.kernel.org/r/db6bbda316048cda7a1bbc9571defde193a8d67e.1602171061.git.iwtbavbm@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handlingNicholas Piggin2020-12-301-1/+5
| | | | | | | | | | | | | | | | | | | [ Upstream commit 8ff00399b153440c1c83e20c43020385b416415b ] powerpc/64s keeps a counter in the mm which counts bits set in mm_cpumask as well as other things. This means it can't use generic code to clear bits out of the mask and doesn't adjust the arch specific counter. Add an arch override that allows powerpc/64s to use clear_tasks_mm_cpumask(). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201126102530.691335-4-npiggin@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* tracing: Fix userstacktrace option for instancesSteven Rostedt (VMware)2020-12-112-5/+8
| | | | | | | | | | | | | | | commit bcee5278958802b40ee8b26679155a6d9231783e upstream. When the instances were able to use their own options, the userstacktrace option was left hardcoded for the top level. This made the instance userstacktrace option bascially into a nop, and will confuse users that set it, but nothing happens (I was confused when it happened to me!) Cc: stable@vger.kernel.org Fixes: 16270145ce6b ("tracing: Add trace options for core options to instances") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ftrace: Fix updating FTRACE_FL_TRAMPNaveen N. Rao2020-12-111-1/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4c75b0ff4e4bf7a45b5aef9639799719c28d0073 upstream. On powerpc, kprobe-direct.tc triggered FTRACE_WARN_ON() in ftrace_get_addr_new() followed by the below message: Bad trampoline accounting at: 000000004222522f (wake_up_process+0xc/0x20) (f0000001) The set of steps leading to this involved: - modprobe ftrace-direct-too - enable_probe - modprobe ftrace-direct - rmmod ftrace-direct <-- trigger The problem turned out to be that we were not updating flags in the ftrace record properly. From the above message about the trampoline accounting being bad, it can be seen that the ftrace record still has FTRACE_FL_TRAMP set though ftrace-direct module is going away. This happens because we are checking if any ftrace_ops has the FTRACE_FL_TRAMP flag set _before_ updating the filter hash. The fix for this is to look for any _other_ ftrace_ops that also needs FTRACE_FL_TRAMP. Link: https://lkml.kernel.org/r/56c113aa9c3e10c19144a36d9684c7882bf09af5.1606412433.git.naveen.n.rao@linux.vnet.ibm.com Cc: stable@vger.kernel.org Fixes: a124692b698b0 ("ftrace: Enable trampoline when rec count returns back to one") Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Remove WARN_ON in start_thread()Vasily Averin2020-12-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 310e3a4b5a4fc718a72201c1e4cf5c64ac6f5442 upstream. This patch reverts commit 978defee11a5 ("tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists") .start hook can be legally called several times if according tracer is stopped screen window 1 [root@localhost ~]# echo 1 > /sys/kernel/tracing/events/kmem/kfree/enable [root@localhost ~]# echo 1 > /sys/kernel/tracing/options/pause-on-trace [root@localhost ~]# less -F /sys/kernel/tracing/trace screen window 2 [root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on 0 [root@localhost ~]# echo hwlat > /sys/kernel/debug/tracing/current_tracer [root@localhost ~]# echo 1 > /sys/kernel/debug/tracing/tracing_on [root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on 0 [root@localhost ~]# echo 2 > /sys/kernel/debug/tracing/tracing_on triggers warning in dmesg: WARNING: CPU: 3 PID: 1403 at kernel/trace/trace_hwlat.c:371 hwlat_tracer_start+0xc9/0xd0 Link: https://lkml.kernel.org/r/bd4d3e70-400d-9c82-7b73-a2d695e86b58@virtuozzo.com Cc: Ingo Molnar <mingo@redhat.com> Cc: stable@vger.kernel.org Fixes: 978defee11a5 ("tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists") Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* seccomp: Set PF_SUPERPRIV when checking capabilityMickaël Salaün2020-11-241-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | commit fb14528e443646dd3fd02df4437fcf5265b66baa upstream. Replace the use of security_capable(current_cred(), ...) with ns_capable_noaudit() which set PF_SUPERPRIV. Since commit 98f368e9e263 ("kernel: Add noaudit variant of ns_capable()"), a new ns_capable_noaudit() helper is available. Let's use it! Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Tyler Hicks <tyhicks@linux.microsoft.com> Cc: Will Drewry <wad@chromium.org> Cc: stable@vger.kernel.org Fixes: e2cfabdfd075 ("seccomp: add system call filtering using BPF") Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Jann Horn <jannh@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201030123849.770769-3-mic@digikod.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ptrace: Set PF_SUPERPRIV when checking capabilityMickaël Salaün2020-11-241-11/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit cf23705244c947151179f929774fabf71e239eee upstream. Commit 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") replaced the use of ns_capable() with has_ns_capability{,_noaudit}() which doesn't set PF_SUPERPRIV. Commit 6b3ad6649a4c ("ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()") replaced has_ns_capability{,_noaudit}() with security_capable(), which doesn't set PF_SUPERPRIV neither. Since commit 98f368e9e263 ("kernel: Add noaudit variant of ns_capable()"), a new ns_capable_noaudit() helper is available. Let's use it! As a result, the signature of ptrace_has_cap() is restored to its original one. Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Eric Paris <eparis@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Tyler Hicks <tyhicks@linux.microsoft.com> Cc: stable@vger.kernel.org Fixes: 6b3ad6649a4c ("ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()") Fixes: 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Jann Horn <jannh@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201030123849.770769-2-mic@digikod.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* fail_function: Remove a redundant mutex unlockLuo Meng2020-11-241-2/+3
| | | | | | | | | | | | | | | | [ Upstream commit 2801a5da5b25b7af9dd2addd19b2315c02d17b64 ] Fix a mutex_unlock() issue where before copy_from_user() is not called mutex_locked. Fixes: 4b1a29a7f542 ("error-injection: Support fault injection framework") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Luo Meng <luomeng12@huawei.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lore.kernel.org/bpf/160570737118.263807.8358435412898356284.stgit@devnote2 Signed-off-by: Sasha Levin <sashal@kernel.org>
* reboot: fix overflow parsing reboot cpu numberMatteo Croce2020-11-181-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit df5b0ab3e08a156701b537809914b339b0daa526 upstream. Limit the CPU number to num_possible_cpus(), because setting it to a value lower than INT_MAX but higher than NR_CPUS produces the following error on reboot and shutdown: BUG: unable to handle page fault for address: ffffffff90ab1bb0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1c09067 P4D 1c09067 PUD 1c0a063 PMD 0 Oops: 0000 [#1] SMP CPU: 1 PID: 1 Comm: systemd-shutdow Not tainted 5.9.0-rc8-kvm #110 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 RIP: 0010:migrate_to_reboot_cpu+0xe/0x60 Code: ea ea 00 48 89 fa 48 c7 c7 30 57 f1 81 e9 fa ef ff ff 66 2e 0f 1f 84 00 00 00 00 00 53 8b 1d d5 ea ea 00 e8 14 33 fe ff 89 da <48> 0f a3 15 ea fc bd 00 48 89 d0 73 29 89 c2 c1 e8 06 65 48 8b 3c RSP: 0018:ffffc90000013e08 EFLAGS: 00010246 RAX: ffff88801f0a0000 RBX: 0000000077359400 RCX: 0000000000000000 RDX: 0000000077359400 RSI: 0000000000000002 RDI: ffffffff81c199e0 RBP: ffffffff81c1e3c0 R08: ffff88801f41f000 R09: ffffffff81c1e348 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 00007f32bedf8830 R14: 00000000fee1dead R15: 0000000000000000 FS: 00007f32bedf8980(0000) GS:ffff88801f480000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff90ab1bb0 CR3: 000000001d057000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __do_sys_reboot.cold+0x34/0x5b do_syscall_64+0x2d/0x40 Fixes: 1b3a5d02ee07 ("reboot: move arch/x86 reboot= handling to generic kernel") Signed-off-by: Matteo Croce <mcroce@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Fabian Frederick <fabf@skynet.be> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Kees Cook <keescook@chromium.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Robin Holt <robinmholt@gmail.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201103214025.116799-3-mcroce@linux.microsoft.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [sudip: use reboot_mode instead of mode] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint"Matteo Croce2020-11-181-14/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 8b92c4ff4423aa9900cf838d3294fcade4dbda35 upstream. Patch series "fix parsing of reboot= cmdline", v3. The parsing of the reboot= cmdline has two major errors: - a missing bound check can crash the system on reboot - parsing of the cpu number only works if specified last Fix both. This patch (of 2): This reverts commit 616feab753972b97. kstrtoint() and simple_strtoul() have a subtle difference which makes them non interchangeable: if a non digit character is found amid the parsing, the former will return an error, while the latter will just stop parsing, e.g. simple_strtoul("123xyx") = 123. The kernel cmdline reboot= argument allows to specify the CPU used for rebooting, with the syntax `s####` among the other flags, e.g. "reboot=warm,s31,force", so if this flag is not the last given, it's silently ignored as well as the subsequent ones. Fixes: 616feab75397 ("kernel/reboot.c: convert simple_strtoul to kstrtoint") Signed-off-by: Matteo Croce <mcroce@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Petr Mladek <pmladek@suse.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Mike Rapoport <rppt@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Robin Holt <robinmholt@gmail.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201103214025.116799-2-mcroce@linux.microsoft.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [sudip: use reboot_mode instead of mode] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* perf/core: Fix race in the perf_mmap_close() functionJiri Olsa2020-11-181-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit f91072ed1b7283b13ca57fcfbece5a3b92726143 upstream. There's a possible race in perf_mmap_close() when checking ring buffer's mmap_count refcount value. The problem is that the mmap_count check is not atomic because we call atomic_dec() and atomic_read() separately. perf_mmap_close: ... atomic_dec(&rb->mmap_count); ... if (atomic_read(&rb->mmap_count)) goto out_put; <ring buffer detach> free_uid out_put: ring_buffer_put(rb); /* could be last */ The race can happen when we have two (or more) events sharing same ring buffer and they go through atomic_dec() and then they both see 0 as refcount value later in atomic_read(). Then both will go on and execute code which is meant to be run just once. The code that detaches ring buffer is probably fine to be executed more than once, but the problem is in calling free_uid(), which will later on demonstrate in related crashes and refcount warnings, like: refcount_t: addition on 0; use-after-free. ... RIP: 0010:refcount_warn_saturate+0x6d/0xf ... Call Trace: prepare_creds+0x190/0x1e0 copy_creds+0x35/0x172 copy_process+0x471/0x1a80 _do_fork+0x83/0x3a0 __do_sys_wait4+0x83/0x90 __do_sys_clone+0x85/0xa0 do_syscall_64+0x5b/0x1e0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Using atomic decrease and check instead of separated calls. Tested-by: Michael Petlan <mpetlan@redhat.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Wade Mealing <wmealing@redhat.com> Fixes: 9bb5d40cd93c ("perf: Fix mmap() accounting hole"); Link: https://lore.kernel.org/r/20200916115311.GE2301783@krava [sudip: used ring_buffer] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* random32: make prandom_u32() output unpredictableGeorge Spelvin2020-11-181-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c51f8f88d705e06bd696d7510aff22b33eb8e638 upstream. Non-cryptographic PRNGs may have great statistical properties, but are usually trivially predictable to someone who knows the algorithm, given a small sample of their output. An LFSR like prandom_u32() is particularly simple, even if the sample is widely scattered bits. It turns out the network stack uses prandom_u32() for some things like random port numbers which it would prefer are *not* trivially predictable. Predictability led to a practical DNS spoofing attack. Oops. This patch replaces the LFSR with a homebrew cryptographic PRNG based on the SipHash round function, which is in turn seeded with 128 bits of strong random key. (The authors of SipHash have *not* been consulted about this abuse of their algorithm.) Speed is prioritized over security; attacks are rare, while performance is always wanted. Replacing all callers of prandom_u32() is the quick fix. Whether to reinstate a weaker PRNG for uses which can tolerate it is an open question. Commit f227e3ec3b5c ("random32: update the net random state on interrupt and activity") was an earlier attempt at a solution. This patch replaces it. Reported-by: Amit Klein <aksecurity@gmail.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Eric Dumazet <edumazet@google.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: tytso@mit.edu Cc: Florian Westphal <fw@strlen.de> Cc: Marc Plumb <lkml.mplumb@gmail.com> Fixes: f227e3ec3b5c ("random32: update the net random state on interrupt and activity") Signed-off-by: George Spelvin <lkml@sdf.org> Link: https://lore.kernel.org/netdev/20200808152628.GA27941@SDF.ORG/ [ willy: partial reversal of f227e3ec3b5c; moved SIPROUND definitions to prandom.h for later use; merged George's prandom_seed() proposal; inlined siprand_u32(); replaced the net_rand_state[] array with 4 members to fix a build issue; cosmetic cleanups to make checkpatch happy; fixed RANDOM32_SELFTEST build ] [wt: backported to 4.19 -- various context adjustments] Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb"Stefano Stabellini2020-11-181-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit e9696d259d0fb5d239e8c28ca41089838ea76d13 upstream. kernel/dma/swiotlb.c:swiotlb_init gets called first and tries to allocate a buffer for the swiotlb. It does so by calling memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE); If the allocation must fail, no_iotlb_memory is set. Later during initialization swiotlb-xen comes in (drivers/xen/swiotlb-xen.c:xen_swiotlb_init) and given that io_tlb_start is != 0, it thinks the memory is ready to use when actually it is not. When the swiotlb is actually needed, swiotlb_tbl_map_single gets called and since no_iotlb_memory is set the kernel panics. Instead, if swiotlb-xen.c:xen_swiotlb_init knew the swiotlb hadn't been initialized, it would do the initialization itself, which might still succeed. Fix the panic by setting io_tlb_start to 0 on swiotlb initialization failure, and also by setting no_iotlb_memory to false on swiotlb initialization success. Fixes: ac2cbab21f31 ("x86: Don't panic if can not alloc buffer for swiotlb") Reported-by: Elliott Mitchell <ehem+xen@m5p.com> Tested-by: Elliott Mitchell <ehem+xen@m5p.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* don't dump the threads that had been already exiting when zapped.Al Viro2020-11-181-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 77f6ab8b7768cf5e6bdd0e72499270a0671506ee upstream. Coredump logics needs to report not only the registers of the dumping thread, but (since 2.5.43) those of other threads getting killed. Doing that might require extra state saved on the stack in asm glue at kernel entry; signal delivery logics does that (we need to be able to save sigcontext there, at the very least) and so does seccomp. That covers all callers of do_coredump(). Secondary threads get hit with SIGKILL and caught as soon as they reach exit_mm(), which normally happens in signal delivery, so those are also fine most of the time. Unfortunately, it is possible to end up with secondary zapped when it has already entered exit(2) (or, worse yet, is oopsing). In those cases we reach exit_mm() when mm->core_state is already set, but the stack contents is not what we would have in signal delivery. At least on two architectures (alpha and m68k) it leads to infoleaks - we end up with a chunk of kernel stack written into coredump, with the contents consisting of normal C stack frames of the call chain leading to exit_mm() instead of the expected copy of userland registers. In case of alpha we leak 312 bytes of stack. Other architectures (including the regset-using ones) might have similar problems - the normal user of regsets is ptrace and the state of tracee at the time of such calls is special in the same way signal delivery is. Note that had the zapper gotten to the exiting thread slightly later, it wouldn't have been included into coredump anyway - we skip the threads that have already cleared their ->mm. So let's pretend that zapper always loses the race. IOW, have exit_mm() only insert into the dumper list if we'd gotten there from handling a fatal signal[*] As the result, the callers of do_exit() that have *not* gone through get_signal() are not seen by coredump logics as secondary threads. Which excludes voluntary exit()/oopsen/traps/etc. The dumper thread itself is unaffected by that, so seccomp is fine. [*] originally I intended to add a new flag in tsk->flags, but ebiederman pointed out that PF_SIGNALED is already doing just what we need. Cc: stable@vger.kernel.org Fixes: d89f3847def4 ("[PATCH] thread-aware coredumps, 2.5.43-C3") History-tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* futex: Don't enable IRQs unconditionally in put_pi_state()Dan Carpenter2020-11-181-2/+3
| | | | | | | | | | | | | | | | | | | commit 1e106aa3509b86738769775969822ffc1ec21bf4 upstream. The exit_pi_state_list() function calls put_pi_state() with IRQs disabled and is not expecting that IRQs will be enabled inside the function. Use the _irqsave() variant so that IRQs are restored to the original state instead of being enabled unconditionally. Fixes: 153fbd1226fb ("futex: Fix more put_pi_state() vs. exit_pi_state_list() races") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201106085205.GA1159983@mwanda Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* perf: Fix get_recursion_context()Peter Zijlstra2020-11-181-1/+1
| | | | | | | | | | | [ Upstream commit ce0f17fc93f63ee91428af10b7b2ddef38cd19e5 ] One should use in_serving_softirq() to detect SoftIRQ context. Fixes: 96f6d4444302 ("perf_counter: avoid recursion") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20201030151955.120572175@infradead.org Signed-off-by: Sasha Levin <sashal@kernel.org>
* tick/common: Touch watchdog in tick_unfreeze() on all CPUsChunyan Zhang2020-11-181-0/+2
| | | | | | | | | | | | | | | | | | | | | | | commit 5167c506d62dd9ffab73eba23c79b0a8845c9fe1 upstream. Suspend to IDLE invokes tick_unfreeze() on resume. tick_unfreeze() on the first resuming CPU resumes timekeeping, which also has the side effect of resetting the softlockup watchdog on this CPU. But on the secondary CPUs the watchdog is not reset in the resume / unfreeze() path, which can result in false softlockup warnings on those CPUs depending on the time spent in suspend. Prevent this by clearing the softlock watchdog in the unfreeze path also on the secondary resuming CPUs. [ tglx: Massaged changelog ] Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200110083902.27276-1-chunyan.zhang@unisoc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* genirq: Let GENERIC_IRQ_IPI select IRQ_DOMAIN_HIERARCHYMarc Zyngier2020-11-181-0/+1
| | | | | | | | | | | | | | [ Upstream commit 151a535171be6ff824a0a3875553ea38570f4c05 ] kernel/irq/ipi.c otherwise fails to compile if nothing else selects it. Fixes: 379b656446a3 ("genirq: Add GENERIC_IRQ_IPI Kconfig symbol") Reported-by: Pavel Machek <pavel@ucw.cz> Tested-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201015101222.GA32747@amd Signed-off-by: Sasha Levin <sashal@kernel.org>
* time: Prevent undefined behaviour in timespec64_to_ns()Zeng Tao2020-11-181-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit cb47755725da7b90fecbb2aa82ac3b24a7adb89b ] UBSAN reports: Undefined behaviour in ./include/linux/time64.h:127:27 signed integer overflow: 17179869187 * 1000000000 cannot be represented in type 'long long int' Call Trace: timespec64_to_ns include/linux/time64.h:127 [inline] set_cpu_itimer+0x65c/0x880 kernel/time/itimer.c:180 do_setitimer+0x8e/0x740 kernel/time/itimer.c:245 __x64_sys_setitimer+0x14c/0x2c0 kernel/time/itimer.c:336 do_syscall_64+0xa1/0x540 arch/x86/entry/common.c:295 Commit bd40a175769d ("y2038: itimer: change implementation to timespec64") replaced the original conversion which handled time clamping correctly with timespec64_to_ns() which has no overflow protection. Fix it in timespec64_to_ns() as this is not necessarily limited to the usage in itimers. [ tglx: Added comment and adjusted the fixes tag ] Fixes: 361a3bf00582 ("time64: Add time64.h header and define struct timespec64") Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1598952616-6416-1-git-send-email-prime.zeng@hisilicon.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* perf/core: Fix a memory leak in perf_event_parse_addr_filter()kiyin(尹亮)2020-11-101-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 7bdb157cdebbf95a1cd94ed2e01b338714075d00 upstream. As shown through runtime testing, the "filename" allocation is not always freed in perf_event_parse_addr_filter(). There are three possible ways that this could happen: - It could be allocated twice on subsequent iterations through the loop, - or leaked on the success path, - or on the failure path. Clean up the code flow to make it obvious that 'filename' is always freed in the reallocation path and in the two return paths as well. We rely on the fact that kfree(NULL) is NOP and filename is initialized with NULL. This fixes the leak. No other side effects expected. [ Dan Carpenter: cleaned up the code flow & added a changelog. ] [ Ingo Molnar: updated the changelog some more. ] Fixes: 375637bc5249 ("perf/core: Introduce address range filtering") Signed-off-by: "kiyin(尹亮)" <kiyin@tencent.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "Srivatsa S. Bhat" <srivatsa@csail.mit.edu> Cc: Anthony Liguori <aliguori@amazon.com> -- kernel/events/core.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parentEddy Wu2020-11-101-5/+5
| | | | | | | | | | | | | | | commit b4e00444cab4c3f3fec876dc0cccc8cbb0d1a948 upstream. current->group_leader->exit_signal may change during copy_process() if current->real_parent exits. Move the assignment inside tasklist_lock to avoid the race. Signed-off-by: Eddy Wu <eddy_wu@trendmicro.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* futex: Handle transient "ownerless" rtmutex state correctlyMike Galbraith2020-11-101-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 9f5d1c336a10c0d24e83e40b4c1b9539f7dba627 upstream. Gratian managed to trigger the BUG_ON(!newowner) in fixup_pi_state_owner(). This is one possible chain of events leading to this: Task Prio Operation T1 120 lock(F) T2 120 lock(F) -> blocks (top waiter) T3 50 (RT) lock(F) -> boosts T1 and blocks (new top waiter) XX timeout/ -> wakes T2 signal T1 50 unlock(F) -> wakes T3 (rtmutex->owner == NULL, waiter bit is set) T2 120 cleanup -> try_to_take_mutex() fails because T3 is the top waiter and the lower priority T2 cannot steal the lock. -> fixup_pi_state_owner() sees newowner == NULL -> BUG_ON() The comment states that this is invalid and rt_mutex_real_owner() must return a non NULL owner when the trylock failed, but in case of a queued and woken up waiter rt_mutex_real_owner() == NULL is a valid transient state. The higher priority waiter has simply not yet managed to take over the rtmutex. The BUG_ON() is therefore wrong and this is just another retry condition in fixup_pi_state_owner(). Drop the locks, so that T3 can make progress, and then try the fixup again. Gratian provided a great analysis, traces and a reproducer. The analysis is to the point, but it confused the hell out of that tglx dude who had to page in all the futex horrors again. Condensed version is above. [ tglx: Wrote comment and changelog ] Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") Reported-by: Gratian Crisan <gratian.crisan@ni.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/87a6w6x7bb.fsf@ni.com Link: https://lore.kernel.org/r/87sg9pkvf7.fsf@nanos.tec.linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Fix out of bounds write in get_trace_bufQiujun Huang2020-11-101-1/+1
| | | | | | | | | | | | | | | | | | | commit c1acb4ac1a892cf08d27efcb964ad281728b0545 upstream. The nesting count of trace_printk allows for 4 levels of nesting. The nesting counter starts at zero and is incremented before being used to retrieve the current context's buffer. But the index to the buffer uses the nesting counter after it was incremented, and not its original number, which in needs to do. Link: https://lkml.kernel.org/r/20201029161905.4269-1-hqjagain@gmail.com Cc: stable@vger.kernel.org Fixes: 3d9622c12c887 ("tracing: Add barrier to trace_printk() buffer nesting modification") Signed-off-by: Qiujun Huang <hqjagain@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ftrace: Handle tracing when switching between contextSteven Rostedt (VMware)2020-11-102-4/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 726b3d3f141fba6f841d715fc4d8a4a84f02c02a upstream. When an interrupt or NMI comes in and switches the context, there's a delay from when the preempt_count() shows the update. As the preempt_count() is used to detect recursion having each context have its own bit get set when tracing starts, and if that bit is already set, it is considered a recursion and the function exits. But if this happens in that section where context has changed but preempt_count() has not been updated, this will be incorrectly flagged as a recursion. To handle this case, create another bit call TRANSITION and test it if the current context bit is already set. Flag the call as a recursion if the TRANSITION bit is already set, and if not, set it and continue. The TRANSITION bit will be cleared normally on the return of the function that set it, or if the current context bit is clear, set it and clear the TRANSITION bit to allow for another transition between the current context and an even higher one. Cc: stable@vger.kernel.org Fixes: edc15cafcbfa3 ("tracing: Avoid unnecessary multiple recursion checks") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ftrace: Fix recursion check for NMI testSteven Rostedt (VMware)2020-11-101-1/+2
| | | | | | | | | | | | | | | | | | | | | | commit ee11b93f95eabdf8198edd4668bf9102e7248270 upstream. The code that checks recursion will work to only do the recursion check once if there's nested checks. The top one will do the check, the other nested checks will see recursion was already checked and return zero for its "bit". On the return side, nothing will be done if the "bit" is zero. The problem is that zero is returned for the "good" bit when in NMI context. This will set the bit for NMIs making it look like *all* NMI tracing is recursing, and prevent tracing of anything in NMI context! The simple fix is to return "bit + 1" and subtract that bit on the end to get the real bit. Cc: stable@vger.kernel.org Fixes: edc15cafcbfa3 ("tracing: Avoid unnecessary multiple recursion checks") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ring-buffer: Fix recursion protection transitions between interrupt contextSteven Rostedt (VMware)2020-11-101-12/+46
| | | | | | | | | | | | | | | | | | | commit b02414c8f045ab3b9afc816c3735bc98c5c3d262 upstream. The recursion protection of the ring buffer depends on preempt_count() to be correct. But it is possible that the ring buffer gets called after an interrupt comes in but before it updates the preempt_count(). This will trigger a false positive in the recursion code. Use the same trick from the ftrace function callback recursion code which uses a "transition" bit that gets set, to allow for a single recursion for to handle transitions between contexts. Cc: stable@vger.kernel.org Fixes: 567cd4da54ff4 ("ring-buffer: User context bit recursion checking") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kthread_worker: prevent queuing delayed work from timer_fn when it is being ↵Zqiang2020-11-101-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | canceled commit 6993d0fdbee0eb38bfac350aa016f65ad11ed3b1 upstream. There is a small race window when a delayed work is being canceled and the work still might be queued from the timer_fn: CPU0 CPU1 kthread_cancel_delayed_work_sync() __kthread_cancel_work_sync() __kthread_cancel_work() work->canceling++; kthread_delayed_work_timer_fn() kthread_insert_work(); BUG: kthread_insert_work() should not get called when work->canceling is set. Signed-off-by: Zqiang <qiang.zhang@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201014083030.16895-1-qiang.zhang@windriver.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blktrace: fix debugfs use after freeLuis Chamberlain2020-11-101-6/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit bad8e64fb19d3a0de5e564d9a7271c31bd684369 upstream. On commit 6ac93117ab00 ("blktrace: use existing disk debugfs directory") merged on v4.12 Omar fixed the original blktrace code for request-based drivers (multiqueue). This however left in place a possible crash, if you happen to abuse blktrace while racing to remove / add a device. We used to use asynchronous removal of the request_queue, and with that the issue was easier to reproduce. Now that we have reverted to synchronous removal of the request_queue, the issue is still possible to reproduce, its however just a bit more difficult. We essentially run two instances of break-blktrace which add/remove a loop device, and setup a blktrace and just never tear the blktrace down. We do this twice in parallel. This is easily reproduced with the script run_0004.sh from break-blktrace [0]. We can end up with two types of panics each reflecting where we race, one a failed blktrace setup: [ 252.426751] debugfs: Directory 'loop0' with parent 'block' already present! [ 252.432265] BUG: kernel NULL pointer dereference, address: 00000000000000a0 [ 252.436592] #PF: supervisor write access in kernel mode [ 252.439822] #PF: error_code(0x0002) - not-present page [ 252.442967] PGD 0 P4D 0 [ 252.444656] Oops: 0002 [#1] SMP NOPTI [ 252.446972] CPU: 10 PID: 1153 Comm: break-blktrace Tainted: G E 5.7.0-rc2-next-20200420+ #164 [ 252.452673] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 [ 252.456343] RIP: 0010:down_write+0x15/0x40 [ 252.458146] Code: eb ca e8 ae 22 8d ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 55 48 89 fd e8 52 db ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 55 00 75 0f 48 8b 04 25 c0 8b 01 00 48 89 45 08 5d [ 252.463638] RSP: 0018:ffffa626415abcc8 EFLAGS: 00010246 [ 252.464950] RAX: 0000000000000000 RBX: ffff958c25f0f5c0 RCX: ffffff8100000000 [ 252.466727] RDX: 0000000000000001 RSI: ffffff8100000000 RDI: 00000000000000a0 [ 252.468482] RBP: 00000000000000a0 R08: 0000000000000000 R09: 0000000000000001 [ 252.470014] R10: 0000000000000000 R11: ffff958d1f9227ff R12: 0000000000000000 [ 252.471473] R13: ffff958c25ea5380 R14: ffffffff8cce15f1 R15: 00000000000000a0 [ 252.473346] FS: 00007f2e69dee540(0000) GS:ffff958c2fc80000(0000) knlGS:0000000000000000 [ 252.475225] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 252.476267] CR2: 00000000000000a0 CR3: 0000000427d10004 CR4: 0000000000360ee0 [ 252.477526] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 252.478776] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 252.479866] Call Trace: [ 252.480322] simple_recursive_removal+0x4e/0x2e0 [ 252.481078] ? debugfs_remove+0x60/0x60 [ 252.481725] ? relay_destroy_buf+0x77/0xb0 [ 252.482662] debugfs_remove+0x40/0x60 [ 252.483518] blk_remove_buf_file_callback+0x5/0x10 [ 252.484328] relay_close_buf+0x2e/0x60 [ 252.484930] relay_open+0x1ce/0x2c0 [ 252.485520] do_blk_trace_setup+0x14f/0x2b0 [ 252.486187] __blk_trace_setup+0x54/0xb0 [ 252.486803] blk_trace_ioctl+0x90/0x140 [ 252.487423] ? do_sys_openat2+0x1ab/0x2d0 [ 252.488053] blkdev_ioctl+0x4d/0x260 [ 252.488636] block_ioctl+0x39/0x40 [ 252.489139] ksys_ioctl+0x87/0xc0 [ 252.489675] __x64_sys_ioctl+0x16/0x20 [ 252.490380] do_syscall_64+0x52/0x180 [ 252.491032] entry_SYSCALL_64_after_hwframe+0x44/0xa9 And the other on the device removal: [ 128.528940] debugfs: Directory 'loop0' with parent 'block' already present! [ 128.615325] BUG: kernel NULL pointer dereference, address: 00000000000000a0 [ 128.619537] #PF: supervisor write access in kernel mode [ 128.622700] #PF: error_code(0x0002) - not-present page [ 128.625842] PGD 0 P4D 0 [ 128.627585] Oops: 0002 [#1] SMP NOPTI [ 128.629871] CPU: 12 PID: 544 Comm: break-blktrace Tainted: G E 5.7.0-rc2-next-20200420+ #164 [ 128.635595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 [ 128.640471] RIP: 0010:down_write+0x15/0x40 [ 128.643041] Code: eb ca e8 ae 22 8d ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 55 48 89 fd e8 52 db ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 55 00 75 0f 65 48 8b 04 25 c0 8b 01 00 48 89 45 08 5d [ 128.650180] RSP: 0018:ffffa9c3c05ebd78 EFLAGS: 00010246 [ 128.651820] RAX: 0000000000000000 RBX: ffff8ae9a6370240 RCX: ffffff8100000000 [ 128.653942] RDX: 0000000000000001 RSI: ffffff8100000000 RDI: 00000000000000a0 [ 128.655720] RBP: 00000000000000a0 R08: 0000000000000002 R09: ffff8ae9afd2d3d0 [ 128.657400] R10: 0000000000000056 R11: 0000000000000000 R12: 0000000000000000 [ 128.659099] R13: 0000000000000000 R14: 0000000000000003 R15: 00000000000000a0 [ 128.660500] FS: 00007febfd995540(0000) GS:ffff8ae9afd00000(0000) knlGS:0000000000000000 [ 128.662204] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 128.663426] CR2: 00000000000000a0 CR3: 0000000420042003 CR4: 0000000000360ee0 [ 128.664776] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 128.666022] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 128.667282] Call Trace: [ 128.667801] simple_recursive_removal+0x4e/0x2e0 [ 128.668663] ? debugfs_remove+0x60/0x60 [ 128.669368] debugfs_remove+0x40/0x60 [ 128.669985] blk_trace_free+0xd/0x50 [ 128.670593] __blk_trace_remove+0x27/0x40 [ 128.671274] blk_trace_shutdown+0x30/0x40 [ 128.671935] blk_release_queue+0x95/0xf0 [ 128.672589] kobject_put+0xa5/0x1b0 [ 128.673188] disk_release+0xa2/0xc0 [ 128.673786] device_release+0x28/0x80 [ 128.674376] kobject_put+0xa5/0x1b0 [ 128.674915] loop_remove+0x39/0x50 [loop] [ 128.675511] loop_control_ioctl+0x113/0x130 [loop] [ 128.676199] ksys_ioctl+0x87/0xc0 [ 128.676708] __x64_sys_ioctl+0x16/0x20 [ 128.677274] do_syscall_64+0x52/0x180 [ 128.677823] entry_SYSCALL_64_after_hwframe+0x44/0xa9 The common theme here is: debugfs: Directory 'loop0' with parent 'block' already present This crash happens because of how blktrace uses the debugfs directory where it places its files. Upon init we always create the same directory which would be needed by blktrace but we only do this for make_request drivers (multiqueue) block drivers. When you race a removal of these devices with a blktrace setup you end up in a situation where the make_request recursive debugfs removal will sweep away the blktrace files and then later blktrace will also try to remove individual dentries which are already NULL. The inverse is also possible and hence the two types of use after frees. We don't create the block debugfs directory on init for these types of block devices: * request-based block driver block devices * every possible partition * scsi-generic And so, this race should in theory only be possible with make_request drivers. We can fix the UAF by simply re-using the debugfs directory for make_request drivers (multiqueue) and only creating the ephemeral directory for the other type of block devices. The new clarifications on relying on the q->blk_trace_mutex *and* also checking for q->blk_trace *prior* to processing a blktrace ensures the debugfs directories are only created if no possible directory name clashes are possible. This goes tested with: o nvme partitions o ISCSI with tgt, and blktracing against scsi-generic with: o block o tape o cdrom o media changer o blktests This patch is part of the work which disputes the severity of CVE-2019-19770 which shows this issue is not a core debugfs issue, but a misuse of debugfs within blktace. Fixes: 6ac93117ab00 ("blktrace: use existing disk debugfs directory") Reported-by: syzbot+603294af2d01acfdd6da@syzkaller.appspotmail.com Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Omar Sandoval <osandov@fb.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: yu kuai <yukuai3@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> [bwh: Backported to 4.19: open-code queue_is_mq()] Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ptrace: fix task_join_group_stop() for the case when current is tracedOleg Nesterov2020-11-101-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 7b3c36fc4c231ca532120bbc0df67a12f09c1d96 upstream. This testcase #include <stdio.h> #include <unistd.h> #include <signal.h> #include <sys/ptrace.h> #include <sys/wait.h> #include <pthread.h> #include <assert.h> void *tf(void *arg) { return NULL; } int main(void) { int pid = fork(); if (!pid) { kill(getpid(), SIGSTOP); pthread_t th; pthread_create(&th, NULL, tf, NULL); return 0; } waitpid(pid, NULL, WSTOPPED); ptrace(PTRACE_SEIZE, pid, 0, PTRACE_O_TRACECLONE); waitpid(pid, NULL, 0); ptrace(PTRACE_CONT, pid, 0,0); waitpid(pid, NULL, 0); int status; int thread = waitpid(-1, &status, 0); assert(thread > 0 && thread != pid); assert(status == 0x80137f); return 0; } fails and triggers WARN_ON_ONCE(!signr) in do_jobctl_trap(). This is because task_join_group_stop() has 2 problems when current is traced: 1. We can't rely on the "JOBCTL_STOP_PENDING" check, a stopped tracee can be woken up by debugger and it can clone another thread which should join the group-stop. We need to check group_stop_count || SIGNAL_STOP_STOPPED. 2. If SIGNAL_STOP_STOPPED is already set, we should not increment sig->group_stop_count and add JOBCTL_STOP_CONSUME. The new thread should stop without another do_notify_parent_cldstop() report. To clarify, the problem is very old and we should blame ptrace_init_task(). But now that we have task_join_group_stop() it makes more sense to fix this helper to avoid the code duplication. Reported-by: syzbot+3485e3773f7da290eecc@syzkaller.appspotmail.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christian Brauner <christian@brauner.io> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Zhiqiang Liu <liuzhiqiang26@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201019134237.GA18810@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ring-buffer: Return 0 on success from ring_buffer_resize()Qiujun Huang2020-11-051-4/+4
| | | | | | | | | | | | | | | | | | | | | | | commit 0a1754b2a97efa644aa6e84d1db5b17c42251483 upstream. We don't need to check the new buffer size, and the return value had confused resize_buffer_duplicate_size(). ... ret = ring_buffer_resize(trace_buf->buffer, per_cpu_ptr(size_buf->data,cpu_id)->entries, cpu_id); if (ret == 0) per_cpu_ptr(trace_buf->data, cpu_id)->entries = per_cpu_ptr(size_buf->data, cpu_id)->entries; ... Link: https://lkml.kernel.org/r/20201019142242.11560-1-hqjagain@gmail.com Cc: stable@vger.kernel.org Fixes: d60da506cbeb3 ("tracing: Add a resize function to make one buffer equivalent to another buffer") Signed-off-by: Qiujun Huang <hqjagain@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kgdb: Make "kgdbcon" work properly with "kgdb_earlycon"Douglas Anderson2020-11-051-8/+14
| | | | | | | | | | | | | | | | | | | [ Upstream commit b18b099e04f450cdc77bec72acefcde7042bd1f3 ] On my system the kernel processes the "kgdb_earlycon" parameter before the "kgdbcon" parameter. When we setup "kgdb_earlycon" we'll end up in kgdb_register_callbacks() and "kgdb_use_con" won't have been set yet so we'll never get around to starting "kgdbcon". Let's remedy this by detecting that the IO module was already registered when setting "kgdb_use_con" and registering the console then. As part of this, to avoid pre-declaring things, move the handling of the "kgdbcon" further down in the file. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200630151422.1.I4aa062751ff5e281f5116655c976dff545c09a46@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* futex: Fix incorrect should_fail_futex() handlingMateusz Nosek2020-11-051-1/+3
| | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 921c7ebd1337d1a46783d7e15a850e12aed2eaa0 ] If should_futex_fail() returns true in futex_wake_pi(), then the 'ret' variable is set to -EFAULT and then immediately overwritten. So the failure injection is non-functional. Fix it by actually leaving the function and returning -EFAULT. The Fixes tag is kinda blury because the initial commit which introduced failure injection was already sloppy, but the below mentioned commit broke it completely. [ tglx: Massaged changelog ] Fixes: 6b4f4bc9cb22 ("locking/futex: Allow low-level atomic operations to return -EAGAIN") Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200927000858.24219-1-mateusznosek0@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* PM: hibernate: remove the bogus call to get_gendisk() in software_resume()Christoph Hellwig2020-10-301-11/+0
| | | | | | | | | | | | | | | [ Upstream commit 428805c0c5e76ef643b1fbc893edfb636b3d8aef ] get_gendisk grabs a reference on the disk and file operation, so this code will leak both of them while having absolutely no use for the gendisk itself. This effectively reverts commit 2df83fa4bce421f ("PM / Hibernate: Use get_gendisk to verify partition if resume_file is integer format") Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
* sched/features: Fix !CONFIG_JUMP_LABEL caseJuri Lelli2020-10-302-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit a73f863af4ce9730795eab7097fb2102e6854365 ] Commit: 765cc3a4b224e ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds") made sched features static for !CONFIG_SCHED_DEBUG configurations, but overlooked the CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL cases. For the latter echoing changes to /sys/kernel/debug/sched_features has the nasty effect of effectively changing what sched_features reports, but without actually changing the scheduler behaviour (since different translation units get different sysctl_sched_features). Fix CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL configurations by properly restructuring ifdefs. Fixes: 765cc3a4b224e ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds") Co-developed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Patrick Bellasi <patrick.bellasi@matbug.net> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Link: https://lore.kernel.org/r/20201013053114.160628-1-juri.lelli@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* kdb: Fix pager search for multi-line stringsDaniel Thompson2020-10-301-2/+6
| | | | | | | | | | | | | | | | | | | | | [ Upstream commit d081a6e353168f15e63eb9e9334757f20343319f ] Currently using forward search doesn't handle multi-line strings correctly. The search routine replaces line breaks with \0 during the search and, for regular searches ("help | grep Common\n"), there is code after the line has been discarded or printed to replace the break character. However during a pager search ("help\n" followed by "/Common\n") when the string is matched we will immediately return to normal output and the code that should restore the \n becomes unreachable. Fix this by restoring the replaced character when we disable the search mode and update the comment accordingly. Fixes: fb6daa7520f9d ("kdb: Provide forward search at more prompt") Link: https://lore.kernel.org/r/20200909141708.338273-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessarySuren Baghdasaryan2020-10-291-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 67197a4f28d28d0b073ab0427b03cb2ee5382578 ] Currently __set_oom_adj loops through all processes in the system to keep oom_score_adj and oom_score_adj_min in sync between processes sharing their mm. This is done for any task with more that one mm_users, which includes processes with multiple threads (sharing mm and signals). However for such processes the loop is unnecessary because their signal structure is shared as well. Android updates oom_score_adj whenever a tasks changes its role (background/foreground/...) or binds to/unbinds from a service, making it more/less important. Such operation can happen frequently. We noticed that updates to oom_score_adj became more expensive and after further investigation found out that the patch mentioned in "Fixes" introduced a regression. Using Pixel 4 with a typical Android workload, write time to oom_score_adj increased from ~3.57us to ~362us. Moreover this regression linearly depends on the number of multi-threaded processes running on the system. Mark the mm with a new MMF_MULTIPROCESS flag bit when task is created with (CLONE_VM && !CLONE_THREAD && !CLONE_VFORK). Change __set_oom_adj to use MMF_MULTIPROCESS instead of mm_users to decide whether oom_score_adj update should be synchronized between multiple processes. To prevent races between clone() and __set_oom_adj(), when oom_score_adj of the process being cloned might be modified from userspace, we use oom_adj_mutex. Its scope is changed to global. The combination of (CLONE_VM && !CLONE_THREAD) is rarely used except for the case of vfork(). To prevent performance regressions of vfork(), we skip taking oom_adj_mutex and setting MMF_MULTIPROCESS when CLONE_VFORK is specified. Clearing the MMF_MULTIPROCESS flag (when the last process sharing the mm exits) is left out of this patch to keep it simple and because it is believed that this threading model is rare. Should there ever be a need for optimizing that case as well, it can be done by hooking into the exit path, likely following the mm_update_next_owner pattern. With the combination of (CLONE_VM && !CLONE_THREAD && !CLONE_VFORK) being quite rare, the regression is gone after the change is applied. [surenb@google.com: v3] Link: https://lkml.kernel.org/r/20200902012558.2335613-1-surenb@google.com Fixes: 44a70adec910 ("mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj") Reported-by: Tim Murray <timmurray@google.com> Suggested-by: Michal Hocko <mhocko@kernel.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Eugene Syromiatnikov <esyr@redhat.com> Cc: Christian Kellner <christian@kellner.me> Cc: Adrian Reber <areber@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Gladkov <gladkov.alexey@gmail.com> Cc: Michel Lespinasse <walken@google.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Andrei Vagin <avagin@gmail.com> Cc: Bernd Edlinger <bernd.edlinger@hotmail.de> Cc: John Johansen <john.johansen@canonical.com> Cc: Yafang Shao <laoar.shao@gmail.com> Link: https://lkml.kernel.org/r/20200824153036.3201505-1-surenb@google.com Debugged-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* perf: Fix task_function_call() error handlingKajol Jain2020-10-141-2/+3
| | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 6d6b8b9f4fceab7266ca03d194f60ec72bd4b654 ] The error handling introduced by commit: 2ed6edd33a21 ("perf: Add cond_resched() to task_function_call()") looses any return value from smp_call_function_single() that is not {0, -EINVAL}. This is a problem because it will return -EXNIO when the target CPU is offline. Worse, in that case it'll turn into an infinite loop. Fixes: 2ed6edd33a21 ("perf: Add cond_resched() to task_function_call()") Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Barret Rhoden <brho@google.com> Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: https://lkml.kernel.org/r/20200827064732.20860-1-kjain@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* usermodehelper: reset umask to default before executing user processLinus Torvalds2020-10-141-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4013c1496c49615d90d36b9d513eee8e369778e9 upstream. Kernel threads intentionally do CLONE_FS in order to follow any changes that 'init' does to set up the root directory (or cwd). It is admittedly a bit odd, but it avoids the situation where 'init' does some extensive setup to initialize the system environment, and then we execute a usermode helper program, and it uses the original FS setup from boot time that may be very limited and incomplete. [ Both Al Viro and Eric Biederman point out that 'pivot_root()' will follow the root regardless, since it fixes up other users of root (see chroot_fs_refs() for details), but overmounting root and doing a chroot() would not. ] However, Vegard Nossum noticed that the CLONE_FS not only means that we follow the root and current working directories, it also means we share umask with whatever init changed it to. That wasn't intentional. Just reset umask to the original default (0022) before actually starting the usermode helper program. Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ftrace: Move RCU is watching check after recursion checkSteven Rostedt (VMware)2020-10-071-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | commit b40341fad6cc2daa195f8090fd3348f18fff640a upstream. The first thing that the ftrace function callback helper functions should do is to check for recursion. Peter Zijlstra found that when "rcu_is_watching()" had its notrace removed, it caused perf function tracing to crash. This is because the call of rcu_is_watching() is tested before function recursion is checked and and if it is traced, it will cause an infinite recursion loop. rcu_is_watching() should still stay notrace, but to prevent this should never had crashed in the first place. The recursion prevention must be the first thing done in callback functions. Link: https://lore.kernel.org/r/20200929112541.GM2628@hirez.programming.kicks-ass.net Cc: stable@vger.kernel.org Cc: Paul McKenney <paulmck@kernel.org> Fixes: c68c0fa293417 ("ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too") Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACEMuchun Song2020-10-011-3/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | commit 10de795a5addd1962406796a6e13ba6cc0fc6bee upstream. Fix compiler warning(as show below) for !CONFIG_KPROBES_ON_FTRACE. kernel/kprobes.c: In function 'kill_kprobe': kernel/kprobes.c:1116:33: warning: statement with no effect [-Wunused-value] 1116 | #define disarm_kprobe_ftrace(p) (-ENODEV) | ^ kernel/kprobes.c:2154:3: note: in expansion of macro 'disarm_kprobe_ftrace' 2154 | disarm_kprobe_ftrace(p); Link: https://lore.kernel.org/r/20200805142136.0331f7ea@canb.auug.org.au Link: https://lkml.kernel.org/r/20200805172046.19066-1-songmuchun@bytedance.com Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kprobes: Fix to check probe enabled before disarm_kprobe_ftrace()Masami Hiramatsu2020-10-011-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 3031313eb3d549b7ad6f9fbcc52ba04412e3eb9e upstream. Commit 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler") fixed one bug but not completely fixed yet. If we run a kprobe_module.tc of ftracetest, kernel showed a warning as below. # ./ftracetest test.d/kprobe/kprobe_module.tc === Ftrace unit tests === [1] Kprobe dynamic event - probing module ... [ 22.400215] ------------[ cut here ]------------ [ 22.400962] Failed to disarm kprobe-ftrace at trace_printk_irq_work+0x0/0x7e [trace_printk] (-2) [ 22.402139] WARNING: CPU: 7 PID: 200 at kernel/kprobes.c:1091 __disarm_kprobe_ftrace.isra.0+0x7e/0xa0 [ 22.403358] Modules linked in: trace_printk(-) [ 22.404028] CPU: 7 PID: 200 Comm: rmmod Not tainted 5.9.0-rc2+ #66 [ 22.404870] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 [ 22.406139] RIP: 0010:__disarm_kprobe_ftrace.isra.0+0x7e/0xa0 [ 22.406947] Code: 30 8b 03 eb c9 80 3d e5 09 1f 01 00 75 dc 49 8b 34 24 89 c2 48 c7 c7 a0 c2 05 82 89 45 e4 c6 05 cc 09 1f 01 01 e8 a9 c7 f0 ff <0f> 0b 8b 45 e4 eb b9 89 c6 48 c7 c7 70 c2 05 82 89 45 e4 e8 91 c7 [ 22.409544] RSP: 0018:ffffc90000237df0 EFLAGS: 00010286 [ 22.410385] RAX: 0000000000000000 RBX: ffffffff83066024 RCX: 0000000000000000 [ 22.411434] RDX: 0000000000000001 RSI: ffffffff810de8d3 RDI: ffffffff810de8d3 [ 22.412687] RBP: ffffc90000237e10 R08: 0000000000000001 R09: 0000000000000001 [ 22.413762] R10: 0000000000000000 R11: 0000000000000001 R12: ffff88807c478640 [ 22.414852] R13: ffffffff8235ebc0 R14: ffffffffa00060c0 R15: 0000000000000000 [ 22.415941] FS: 00000000019d48c0(0000) GS:ffff88807d7c0000(0000) knlGS:0000000000000000 [ 22.417264] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 22.418176] CR2: 00000000005bb7e3 CR3: 0000000078f7a000 CR4: 00000000000006a0 [ 22.419309] Call Trace: [ 22.419990] kill_kprobe+0x94/0x160 [ 22.420652] kprobes_module_callback+0x64/0x230 [ 22.421470] notifier_call_chain+0x4f/0x70 [ 22.422184] blocking_notifier_call_chain+0x49/0x70 [ 22.422979] __x64_sys_delete_module+0x1ac/0x240 [ 22.423733] do_syscall_64+0x38/0x50 [ 22.424366] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 22.425176] RIP: 0033:0x4bb81d [ 22.425741] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e0 ff ff ff f7 d8 64 89 01 48 [ 22.428726] RSP: 002b:00007ffc70fef008 EFLAGS: 00000246 ORIG_RAX: 00000000000000b0 [ 22.430169] RAX: ffffffffffffffda RBX: 00000000019d48a0 RCX: 00000000004bb81d [ 22.431375] RDX: 0000000000000000 RSI: 0000000000000880 RDI: 00007ffc70fef028 [ 22.432543] RBP: 0000000000000880 R08: 00000000ffffffff R09: 00007ffc70fef320 [ 22.433692] R10: 0000000000656300 R11: 0000000000000246 R12: 00007ffc70fef028 [ 22.434635] R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000000 [ 22.435682] irq event stamp: 1169 [ 22.436240] hardirqs last enabled at (1179): [<ffffffff810df542>] console_unlock+0x422/0x580 [ 22.437466] hardirqs last disabled at (1188): [<ffffffff810df19b>] console_unlock+0x7b/0x580 [ 22.438608] softirqs last enabled at (866): [<ffffffff81c0038e>] __do_softirq+0x38e/0x490 [ 22.439637] softirqs last disabled at (859): [<ffffffff81a00f42>] asm_call_on_stack+0x12/0x20 [ 22.440690] ---[ end trace 1e7ce7e1e4567276 ]--- [ 22.472832] trace_kprobe: This probe might be able to register after target module is loaded. Continue. This is because the kill_kprobe() calls disarm_kprobe_ftrace() even if the given probe is not enabled. In that case, ftrace_set_filter_ip() fails because the given probe point is not registered to ftrace. Fix to check the given (going) probe is enabled before invoking disarm_kprobe_ftrace(). Link: https://lkml.kernel.org/r/159888672694.1411785.5987998076694782591.stgit@devnote2 Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler") Cc: Ingo Molnar <mingo@kernel.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David Miller <davem@davemloft.net> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Chengming Zhou <zhouchengming@bytedance.com> Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: fix double freeTom Rix2020-10-011-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 46bbe5c671e06f070428b9be142cc4ee5cedebac upstream. clang static analyzer reports this problem trace_events_hist.c:3824:3: warning: Attempt to free released memory kfree(hist_data->attrs->var_defs.name[i]); In parse_var_defs() if there is a problem allocating var_defs.expr, the earlier var_defs.name is freed. This free is duplicated by free_var_defs() which frees the rest of the list. Because free_var_defs() has to run anyway, remove the second free fom parse_var_defs(). Link: https://lkml.kernel.org/r/20200907135845.15804-1-trix@redhat.com Cc: stable@vger.kernel.org Fixes: 30350d65ac56 ("tracing: Add variable support to hist triggers") Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Tom Rix <trix@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* bpf: Fix a rcu warning for bpffs map pretty-printYonghong Song2020-10-011-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit ce880cb825fcc22d4e39046a6c3a3a7f6603883d ] Running selftest ./btf_btf -p the kernel had the following warning: [ 51.528185] WARNING: CPU: 3 PID: 1756 at kernel/bpf/hashtab.c:717 htab_map_get_next_key+0x2eb/0x300 [ 51.529217] Modules linked in: [ 51.529583] CPU: 3 PID: 1756 Comm: test_btf Not tainted 5.9.0-rc1+ #878 [ 51.530346] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.el7.centos 04/01/2014 [ 51.531410] RIP: 0010:htab_map_get_next_key+0x2eb/0x300 ... [ 51.542826] Call Trace: [ 51.543119] map_seq_next+0x53/0x80 [ 51.543528] seq_read+0x263/0x400 [ 51.543932] vfs_read+0xad/0x1c0 [ 51.544311] ksys_read+0x5f/0xe0 [ 51.544689] do_syscall_64+0x33/0x40 [ 51.545116] entry_SYSCALL_64_after_hwframe+0x44/0xa9 The related source code in kernel/bpf/hashtab.c: 709 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key) 710 { 711 struct bpf_htab *htab = container_of(map, struct bpf_htab, map); 712 struct hlist_nulls_head *head; 713 struct htab_elem *l, *next_l; 714 u32 hash, key_size; 715 int i = 0; 716 717 WARN_ON_ONCE(!rcu_read_lock_held()); In kernel/bpf/inode.c, bpffs map pretty print calls map->ops->map_get_next_key() without holding a rcu_read_lock(), hence causing the above warning. To fix the issue, just surrounding map->ops->map_get_next_key() with rcu read lock. Fixes: a26ca7c982cb ("bpf: btf: Add pretty print support to the basic arraymap") Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200916004401.146277-1-yhs@fb.com Signed-off-by: Sasha Levin <sashal@kernel.org>
* lockdep: fix order in trace_hardirqs_off_caller()Sven Schnelle2020-10-011-2/+2
| | | | | | | | | | | | [ Upstream commit 73ac74c7d489756d2313219a108809921dbfaea1 ] Switch order so that locking state is consistent even if the IRQ tracer calls into lockdep again. Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 23:21:03 +0000