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* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2021-11-091-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge more updates from Andrew Morton: "87 patches. Subsystems affected by this patch series: mm (pagecache and hugetlb), procfs, misc, MAINTAINERS, lib, checkpatch, binfmt, kallsyms, ramfs, init, codafs, nilfs2, hfs, crash_dump, signals, seq_file, fork, sysvfs, kcov, gdb, resource, selftests, and ipc" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (87 commits) ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL ipc: check checkpoint_restore_ns_capable() to modify C/R proc files selftests/kselftest/runner/run_one(): allow running non-executable files virtio-mem: disallow mapping virtio-mem memory via /dev/mem kernel/resource: disallow access to exclusive system RAM regions kernel/resource: clean up and optimize iomem_is_exclusive() scripts/gdb: handle split debug for vmlinux kcov: replace local_irq_save() with a local_lock_t kcov: avoid enable+disable interrupts if !in_task() kcov: allocate per-CPU memory on the relevant node Documentation/kcov: define `ip' in the example Documentation/kcov: include types.h in the example sysv: use BUILD_BUG_ON instead of runtime check kernel/fork.c: unshare(): use swap() to make code cleaner seq_file: fix passing wrong private data seq_file: move seq_escape() to a header signal: remove duplicate include in signal.h crash_dump: remove duplicate include in crash_dump.h crash_dump: fix boolreturn.cocci warning hfs/hfsplus: use WARN_ON for sanity check ...
| * signal: remove duplicate include in signal.hYe Guojin2021-11-091-1/+0
| | | | | | | | | | | | | | | | | | | | | | 'linux/string.h' included in 'signal.h' is duplicated. it's also included at line 7. Link: https://lkml.kernel.org/r/20211019024934.973008-1-ye.guojin@zte.com.cn Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn> Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | signal: Add an optional check for altstack sizeThomas Gleixner2021-10-261-0/+6
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | New x86 FPU features will be very large, requiring ~10k of stack in signal handlers. These new features require a new approach called "dynamic features". The kernel currently tries to ensure that altstacks are reasonably sized. Right now, on x86, sys_sigaltstack() requires a size of >=2k. However, that 2k is a constant. Simply raising that 2k requirement to >10k for the new features would break existing apps which have a compiled-in size of 2k. Instead of universally enforcing a larger stack, prohibit a process from using dynamic features without properly-sized altstacks. This must be enforced in two places: * A dynamic feature can not be enabled without an large-enough altstack for each process thread. * Once a dynamic feature is enabled, any request to install a too-small altstack will be rejected The dynamic feature enabling code must examine each thread in a process to ensure that the altstacks are large enough. Add a new lock (sigaltstack_lock()) to ensure that threads can not race and change their altstack after being examined. Add the infrastructure in form of a config option and provide empty stubs for architectures which do not need dynamic altstack size checks. This implementation will be fleshed out for x86 in a future patch called x86/arch_prctl: Add controls for dynamic XSTATE components [dhansen: commit message. ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20211021225527.10184-2-chang.seok.bae@intel.com
* signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistencyEric W. Biederman2021-07-231-1/+1
| | | | | | | | | | | It helps to know which part of the siginfo structure the siginfo_layout value is talking about. v1: https://lkml.kernel.org/r/m18s4zs7nu.fsf_-_@fess.ebiederm.org v2: https://lkml.kernel.org/r/20210505141101.11519-9-ebiederm@xmission.com Link: https://lkml.kernel.org/r/87zgumw8cc.fsf_-_@disp2133 Acked-by: Marco Elver <elver@google.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* x86: signal: don't do sas_ss_reset() until we are certain that sigframe ↵Al Viro2021-07-011-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | won't be abandoned Currently we handle SS_AUTODISARM as soon as we have stored the altstack settings into sigframe - that's the point when we have set the things up for eventual sigreturn to restore the old settings. And if we manage to set the sigframe up (we are not done with that yet), everything's fine. However, in case of failure we end up with sigframe-to-be abandoned and SIGSEGV force-delivered. And in that case we end up with inconsistent rules - late failures have altstack reset, early ones do not. It's trivial to get consistent behaviour - just handle SS_AUTODISARM once we have set the sigframe up and are committed to entering the handler, i.e. in signal_delivered(). Link: https://lore.kernel.org/lkml/20200404170604.GN23230@ZenIV.linux.org.uk/ Link: https://github.com/ClangBuiltLinux/linux/issues/876 Link: https://lkml.kernel.org/r/20210422230846.1756380-1-ndesaulniers@google.com Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "signal: Allow tasks to cache one sigqueue struct"Linus Torvalds2021-06-271-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commits 4bad58ebc8bc4f20d89cff95417c9b4674769709 (and 399f8dd9a866e107639eabd3c1979cd526ca3a98, which tried to fix it). I do not believe these are correct, and I'm about to release 5.13, so am reverting them out of an abundance of caution. The locking is odd, and appears broken. On the allocation side (in __sigqueue_alloc()), the locking is somewhat straightforward: it depends on sighand->siglock. Since one caller doesn't hold that lock, it further then tests 'sigqueue_flags' to avoid the case with no locks held. On the freeing side (in sigqueue_cache_or_free()), there is no locking at all, and the logic instead depends on 'current' being a single thread, and not able to race with itself. To make things more exciting, there's also the data race between freeing a signal and allocating one, which is handled by using WRITE_ONCE() and READ_ONCE(), and being mutually exclusive wrt the initial state (ie freeing will only free if the old state was NULL, while allocating will obviously only use the value if it was non-NULL, so only one or the other will actually act on the value). However, while the free->alloc paths do seem mutually exclusive thanks to just the data value dependency, it's not clear what the memory ordering constraints are on it. Could writes from the previous allocation possibly be delayed and seen by the new allocation later, causing logical inconsistencies? So it's all very exciting and unusual. And in particular, it seems that the freeing side is incorrect in depending on "current" being single-threaded. Yes, 'current' is a single thread, but in the presense of asynchronous events even a single thread can have data races. And such asynchronous events can and do happen, with interrupts causing signals to be flushed and thus free'd (for example - sending a SIGCONT/SIGSTOP can happen from interrupt context, and can flush previously queued process control signals). So regardless of all the other questions about the memory ordering and locking for this new cached allocation, the sigqueue_cache_or_free() assumptions seem to be fundamentally incorrect. It may be that people will show me the errors of my ways, and tell me why this is all safe after all. We can reinstate it if so. But my current belief is that the WRITE_ONCE() that sets the cached entry needs to be a smp_store_release(), and the READ_ONCE() that finds a cached entry needs to be a smp_load_acquire() to handle memory ordering correctly. And the sequence in sigqueue_cache_or_free() would need to either use a lock or at least be interrupt-safe some way (perhaps by using something like the percpu 'cmpxchg': it doesn't need to be SMP-safe, but like the percpu operations it needs to be interrupt-safe). Fixes: 399f8dd9a866 ("signal: Prevent sigqueue caching after task got released") Fixes: 4bad58ebc8bc ("signal: Allow tasks to cache one sigqueue struct") Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-v5.13-rc3' of ↵Linus Torvalds2021-05-211-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull siginfo fix from Eric Biederman: "During the merge window an issue with si_perf and the siginfo ABI came up. The alpha and sparc siginfo structure layout had changed with the addition of SIGTRAP TRAP_PERF and the new field si_perf. The reason only alpha and sparc were affected is that they are the only architectures that use si_trapno. Looking deeper it was discovered that si_trapno is used for only a few select signals on alpha and sparc, and that none of the other _sigfault fields past si_addr are used at all. Which means technically no regression on alpha and sparc. While the alignment concerns might be dismissed the abuse of si_errno by SIGTRAP TRAP_PERF does have the potential to cause regressions in existing userspace. While we still have time before userspace starts using and depending on the new definition siginfo for SIGTRAP TRAP_PERF this set of changes cleans up siginfo_t. - The si_trapno field is demoted from magic alpha and sparc status and made an ordinary union member of the _sigfault member of siginfo_t. Without moving it of course. - si_perf is replaced with si_perf_data and si_perf_type ending the abuse of si_errno. - Unnecessary additions to signalfd_siginfo are removed" * 'for-v5.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo signal: Deliver all of the siginfo perf data in _perf signal: Factor force_sig_perf out of perf_sigtrap signal: Implement SIL_FAULT_TRAPNO siginfo: Move si_trapno inside the union inside _si_fault
| * signal: Implement SIL_FAULT_TRAPNOEric W. Biederman2021-05-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that si_trapno is part of the union in _si_fault and available on all architectures, add SIL_FAULT_TRAPNO and update siginfo_layout to return SIL_FAULT_TRAPNO when the code assumes si_trapno is valid. There is room for future changes to reduce when si_trapno is valid but this is all that is needed to make si_trapno and the other members of the the union in _sigfault mutually exclusive. Update the code that uses siginfo_layout to deal with SIL_FAULT_TRAPNO and have the same code ignore si_trapno in in all other cases. v1: https://lkml.kernel.org/r/m1o8dvs7s7.fsf_-_@fess.ebiederm.org v2: https://lkml.kernel.org/r/20210505141101.11519-6-ebiederm@xmission.com Link: https://lkml.kernel.org/r/20210517195748.8880-2-ebiederm@xmission.com Reviewed-by: Marco Elver <elver@google.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | Merge tag 'sched-core-2021-04-28' of ↵Linus Torvalds2021-04-281-0/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - Clean up SCHED_DEBUG: move the decades old mess of sysctl, procfs and debugfs interfaces to a unified debugfs interface. - Signals: Allow caching one sigqueue object per task, to improve performance & latencies. - Improve newidle_balance() irq-off latencies on systems with a large number of CPU cgroups. - Improve energy-aware scheduling - Improve the PELT metrics for certain workloads - Reintroduce select_idle_smt() to improve load-balancing locality - but without the previous regressions - Add 'scheduler latency debugging': warn after long periods of pending need_resched. This is an opt-in feature that requires the enabling of the LATENCY_WARN scheduler feature, or the use of the resched_latency_warn_ms=xx boot parameter. - CPU hotplug fixes for HP-rollback, and for the 'fail' interface. Fix remaining balance_push() vs. hotplug holes/races - PSI fixes, plus allow /proc/pressure/ files to be written by CAP_SYS_RESOURCE tasks as well - Fix/improve various load-balancing corner cases vs. capacity margins - Fix sched topology on systems with NUMA diameter of 3 or above - Fix PF_KTHREAD vs to_kthread() race - Minor rseq optimizations - Misc cleanups, optimizations, fixes and smaller updates * tag 'sched-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits) cpumask/hotplug: Fix cpu_dying() state tracking kthread: Fix PF_KTHREAD vs to_kthread() race sched/debug: Fix cgroup_path[] serialization sched,psi: Handle potential task count underflow bugs more gracefully sched: Warn on long periods of pending need_resched sched/fair: Move update_nohz_stats() to the CONFIG_NO_HZ_COMMON block to simplify the code & fix an unused function warning sched/debug: Rename the sched_debug parameter to sched_verbose sched,fair: Alternative sched_slice() sched: Move /proc/sched_debug to debugfs sched,debug: Convert sysctl sched_domains to debugfs debugfs: Implement debugfs_create_str() sched,preempt: Move preempt_dynamic to debug.c sched: Move SCHED_DEBUG sysctl to debugfs sched: Don't make LATENCYTOP select SCHED_DEBUG sched: Remove sched_schedstats sysctl out from under SCHED_DEBUG sched/numa: Allow runtime enabling/disabling of NUMA balance without SCHED_DEBUG sched: Use cpu_dying() to fix balance_push vs hotplug-rollback cpumask: Introduce DYING mask cpumask: Make cpu_{online,possible,present,active}() inline rseq: Optimise rseq_get_rseq_cs() and clear_rseq_cs() ...
| * signal: Allow tasks to cache one sigqueue structThomas Gleixner2021-04-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The idea for this originates from the real time tree to make signal delivery for realtime applications more efficient. In quite some of these application scenarios a control tasks signals workers to start their computations. There is usually only one signal per worker on flight. This works nicely as long as the kmem cache allocations do not hit the slow path and cause latencies. To cure this an optimistic caching was introduced (limited to RT tasks) which allows a task to cache a single sigqueue in a pointer in task_struct instead of handing it back to the kmem cache after consuming a signal. When the next signal is sent to the task then the cached sigqueue is used instead of allocating a new one. This solved the problem for this set of application scenarios nicely. The task cache is not preallocated so the first signal sent to a task goes always to the cache allocator. The cached sigqueue stays around until the task exits and is freed when task::sighand is dropped. After posting this solution for mainline the discussion came up whether this would be useful in general and should not be limited to realtime tasks: https://lore.kernel.org/r/m11rcu7nbr.fsf@fess.ebiederm.org One concern leading to the original limitation was to avoid a large amount of pointlessly cached sigqueues in alive tasks. The other concern was vs. RLIMIT_SIGPENDING as these cached sigqueues are not accounted for. The accounting problem is real, but on the other hand slightly academic. After gathering some statistics it turned out that after boot of a regular distro install there are less than 10 sigqueues cached in ~1500 tasks. In case of a 'mass fork and fire signal to child' scenario the extra 80 bytes of memory per task are well in the noise of the overall memory consumption of the fork bomb. If this should be limited then this would need an extra counter in struct user, more atomic instructions and a seperate rlimit. Yet another tunable which is mostly unused. The caching is actually used. After boot and a full kernel compile on a 64CPU machine with make -j128 the number of 'allocations' looks like this: From slab: 23996 From task cache: 52223 I.e. it reduces the number of slab cache operations by ~68%. A typical pattern there is: <...>-58490 __sigqueue_alloc: for 58488 from slab ffff8881132df460 <...>-58488 __sigqueue_free: cache ffff8881132df460 <...>-58488 __sigqueue_alloc: for 1149 from cache ffff8881103dc550 bash-1149 exit_task_sighand: free ffff8881132df460 bash-1149 __sigqueue_free: cache ffff8881103dc550 The interesting sequence is that the exiting task 58488 grabs the sigqueue from bash's task cache to signal exit and bash sticks it back into it's own cache. Lather, rinse and repeat. The caching is probably not noticable for the general use case, but the benefit for latency sensitive applications is clear. While kmem caches are usually just serving from the fast path the slab merging (default) can depending on the usage pattern of the merged slabs cause occasional slow path allocations. The time spared per cached entry is a few micro seconds per signal which is not relevant for e.g. a kernel build, but for signal heavy workloads it's measurable. As there is no real downside of this caching mechanism making it unconditionally available is preferred over more conditional code or new magic tunables. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/87sg4lbmxo.fsf@nanos.tec.linutronix.de
* | signal: Introduce TRAP_PERF si_code and si_perf to siginfoMarco Elver2021-04-161-0/+1
|/ | | | | | | | | | | | Introduces the TRAP_PERF si_code, and associated siginfo_t field si_perf. These will be used by the perf event subsystem to send signals (if requested) to the task where an event occurred. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k Acked-by: Arnd Bergmann <arnd@arndb.de> # asm-generic Link: https://lkml.kernel.org/r/20210408103605.1676875-6-elver@google.com
* signal: define the SA_EXPOSE_TAGBITS bit in sa_flagsPeter Collingbourne2020-11-231-0/+14
| | | | | | | | | | | | | | | | | | | | Architectures that support address tagging, such as arm64, may want to expose fault address tag bits to the signal handler to help diagnose memory errors. However, these bits have not been previously set, and their presence may confuse unaware user applications. Therefore, introduce a SA_EXPOSE_TAGBITS flag bit in sa_flags that a signal handler may use to explicitly request that the bits are set. The generic signal handler APIs expect to receive tagged addresses. Architectures may specify how to untag addresses in the case where SA_EXPOSE_TAGBITS is clear by defining the arch_untagged_si_addr function. Signed-off-by: Peter Collingbourne <pcc@google.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Link: https://linux-review.googlesource.com/id/I16dd0ed2081f091fce97be0190cb8caa874c26cb Link: https://lkml.kernel.org/r/13cf24d00ebdd8e1f55caf1821c7c29d54100191.1605904350.git.pcc@google.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* include: jhash/signal: Fix fall-through warnings for ClangGustavo A. R. Silva2020-10-291-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation to enable -Wimplicit-fallthrough for Clang, explicitly add break statements instead of letting the code fall through to the next case. This patch adds four break statements that, together, fix almost 40,000 warnings when building Linux 5.10-rc1 with Clang 12.0.0 and this[1] change reverted. Notice that in order to enable -Wimplicit-fallthrough for Clang, such change[1] is meant to be reverted at some point. So, this patch helps to move in that direction. Something important to mention is that there is currently a discrepancy between GCC and Clang when dealing with switch fall-through to empty case statements or to cases that only contain a break/continue/return statement[2][3][4]. Now that the -Wimplicit-fallthrough option has been globally enabled[5], any compiler should really warn on missing either a fallthrough annotation or any of the other case-terminating statements (break/continue/return/ goto) when falling through to the next case statement. Making exceptions to this introduces variation in case handling which may continue to lead to bugs, misunderstandings, and a general lack of robustness. The point of enabling options like -Wimplicit-fallthrough is to prevent human error and aid developers in spotting bugs before their code is even built/ submitted/committed, therefore eliminating classes of bugs. So, in order to really accomplish this, we should, and can, move in the direction of addressing any error-prone scenarios and get rid of the unintentional fallthrough bug-class in the kernel, entirely, even if there is some minor redundancy. Better to have explicit case-ending statements than continue to have exceptions where one must guess as to the right result. The compiler will eliminate any actual redundancy. [1] commit e2079e93f562c ("kbuild: Do not enable -Wimplicit-fallthrough for clang for now") [2] https://github.com/ClangBuiltLinux/linux/issues/636 [3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91432 [4] https://godbolt.org/z/xgkvIh [5] commit a035d552a93b ("Makefile: Globally enable fall-through warning") Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva2020-08-231-6/+6
| | | | | | | | | | Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* binfmt_elf: remove the set_fs in fill_siginfo_noteEric W. Biederman2020-05-051-0/+8
| | | | | | | | | | | | | | | | | | | | | The code in binfmt_elf.c is differnt from the rest of the code that processes siginfo, as it sends siginfo from a kernel buffer to a file rather than from kernel memory to userspace buffers. To remove it's use of set_fs the code needs some different siginfo helpers. Add the helper copy_siginfo_to_external to copy from the kernel's internal siginfo layout to a buffer in the siginfo layout that userspace expects. Modify fill_siginfo_note to use copy_siginfo_to_external instead of set_fs and copy_siginfo_to_user. Update compat_binfmt_elf.c to use the previously added copy_siginfo_to_external32 to handle the compat case. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* x86: get rid of put_user_try in __setup_rt_frame() (both 32bit and 64bit)Al Viro2020-03-261-4/+4
| | | | | | | | | Straightforward, except for save_altstack_ex() stuck in those. Replace that thing with an analogue that would use unsafe_put_user() instead of put_user_ex() (called compat_save_altstack()) and be done with that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* signal: Allow cifs and drbd to receive their terminating signalsEric W. Biederman2019-08-191-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My recent to change to only use force_sig for a synchronous events wound up breaking signal reception cifs and drbd. I had overlooked the fact that by default kthreads start out with all signals set to SIG_IGN. So a change I thought was safe turned out to have made it impossible for those kernel thread to catch their signals. Reverting the work on force_sig is a bad idea because what the code was doing was very much a misuse of force_sig. As the way force_sig ultimately allowed the signal to happen was to change the signal handler to SIG_DFL. Which after the first signal will allow userspace to send signals to these kernel threads. At least for wake_ack_receiver in drbd that does not appear actively wrong. So correct this problem by adding allow_kernel_signal that will allow signals whose siginfo reports they were sent by the kernel through, but will not allow userspace generated signals, and update cifs and drbd to call allow_kernel_signal in an appropriate place so that their thread can receive this signal. Fixing things this way ensures that userspace won't be able to send signals and cause problems, that it is clear which signals the threads are expecting to receive, and it guarantees that nothing else in the system will be affected. This change was partly inspired by similar cifs and drbd patches that added allow_signal. Reported-by: ronnie sahlberg <ronniesahlberg@gmail.com> Reported-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Tested-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Cc: Steve French <smfrench@gmail.com> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: David Laight <David.Laight@ACULAB.COM> Fixes: 247bc9470b1e ("cifs: fix rmmod regression in cifs.ko caused by force_sig changes") Fixes: 72abe3bcf091 ("signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sig") Fixes: fee109901f39 ("signal/drbd: Use send_sig not force_sig") Fixes: 3cf5d076fb4d ("signal: Remove task parameter from force_sig") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: simplify set_user_sigmask/restore_user_sigmaskOleg Nesterov2019-07-161-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | task->saved_sigmask and ->restore_sigmask are only used in the ret-from- syscall paths. This means that set_user_sigmask() can save ->blocked in ->saved_sigmask and do set_restore_sigmask() to indicate that ->blocked was modified. This way the callers do not need 2 sigset_t's passed to set/restore and restore_user_sigmask() renamed to restore_saved_sigmask_unless() turns into the trivial helper which just calls restore_saved_sigmask(). Link: http://lkml.kernel.org/r/20190606113206.GA9464@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Deepa Dinamani <deepa.kernel@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Eric Wong <e@80x24.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: David Laight <David.Laight@aculab.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signal: remove the wrong signal_pending() check in restore_user_sigmask()Oleg Nesterov2019-06-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the minimal fix for stable, I'll send cleanups later. Commit 854a6ed56839 ("signal: Add restore_user_sigmask()") introduced the visible change which breaks user-space: a signal temporary unblocked by set_user_sigmask() can be delivered even if the caller returns success or timeout. Change restore_user_sigmask() to accept the additional "interrupted" argument which should be used instead of signal_pending() check, and update the callers. Eric said: : For clarity. I don't think this is required by posix, or fundamentally to : remove the races in select. It is what linux has always done and we have : applications who care so I agree this fix is needed. : : Further in any case where the semantic change that this patch rolls back : (aka where allowing a signal to be delivered and the select like call to : complete) would be advantage we can do as well if not better by using : signalfd. : : Michael is there any chance we can get this guarantee of the linux : implementation of pselect and friends clearly documented. The guarantee : that if the system call completes successfully we are guaranteed that no : signal that is unblocked by using sigmask will be delivered? Link: http://lkml.kernel.org/r/20190604134117.GA29963@redhat.com Fixes: 854a6ed56839a40f6b5d02a2962f48841482eec4 ("signal: Add restore_user_sigmask()") Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Eric Wong <e@80x24.org> Tested-by: Eric Wong <e@80x24.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Deepa Dinamani <deepa.kernel@gmail.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Jason Baron <jbaron@akamai.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: David Laight <David.Laight@ACULAB.COM> Cc: <stable@vger.kernel.org> [5.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signal: Make siginmask safe when passed a signal of 0Eric W. Biederman2019-01-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eric Biggers reported: > The following commit, which went into v4.20, introduced undefined behavior when > sys_rt_sigqueueinfo() is called with sig=0: > > commit 4ce5f9c9e7546915c559ffae594e6d73f918db00 > Author: Eric W. Biederman <ebiederm@xmission.com> > Date: Tue Sep 25 12:59:31 2018 +0200 > > signal: Use a smaller struct siginfo in the kernel > > In sig_specific_sicodes(), used from known_siginfo_layout(), the expression > '1ULL << ((sig)-1)' is undefined as it evaluates to 1ULL << 4294967295. > > Reproducer: > > #include <signal.h> > #include <sys/syscall.h> > #include <unistd.h> > > int main(void) > { > siginfo_t si = { .si_code = 1 }; > syscall(__NR_rt_sigqueueinfo, 0, 0, &si); > } > > UBSAN report for v5.0-rc1: > > UBSAN: Undefined behaviour in kernel/signal.c:2946:7 > shift exponent 4294967295 is too large for 64-bit type 'long unsigned int' > CPU: 2 PID: 346 Comm: syz_signal Not tainted 5.0.0-rc1 #25 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x70/0xa5 lib/dump_stack.c:113 > ubsan_epilogue+0xd/0x40 lib/ubsan.c:159 > __ubsan_handle_shift_out_of_bounds+0x12c/0x170 lib/ubsan.c:425 > known_siginfo_layout+0xae/0xe0 kernel/signal.c:2946 > post_copy_siginfo_from_user kernel/signal.c:3009 [inline] > __copy_siginfo_from_user+0x35/0x60 kernel/signal.c:3035 > __do_sys_rt_sigqueueinfo kernel/signal.c:3553 [inline] > __se_sys_rt_sigqueueinfo kernel/signal.c:3549 [inline] > __x64_sys_rt_sigqueueinfo+0x31/0x70 kernel/signal.c:3549 > do_syscall_64+0x4c/0x1b0 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x433639 > Code: c4 18 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 0f 83 7b 27 00 00 c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007fffcb289fc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000081 > RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000433639 > RDX: 00007fffcb289fd0 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 00000000006b2018 R08: 000000000000004d R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401560 > R13: 00000000004015f0 R14: 0000000000000000 R15: 0000000000000000 I have looked at the other callers of siginmask and they all appear to in locations where sig can not be zero. I have looked at the code generation of adding an extra test against zero and gcc was able with a simple decrement instruction to combine the two tests together. So the at most adding this test cost a single cpu cycle. In practice that decrement instruction was already present as part of the mask comparison, so the only change was when the instruction was executed. So given that it is cheap, and obviously correct to update siginmask to verify the signal is not zero. Fix this issue there to avoid any future problems. Reported-by: Eric Biggers <ebiggers@kernel.org> Fixes: 4ce5f9c9e754 ("signal: Use a smaller struct siginfo in the kernel") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Add restore_user_sigmask()Deepa Dinamani2018-12-061-0/+2
| | | | | | | | | | | | | | | | | Refactor the logic to restore the sigmask before the syscall returns into an api. This is useful for versions of syscalls that pass in the sigmask and expect the current->sigmask to be changed during the execution and restored after the execution of the syscall. With the advent of new y2038 syscalls in the subsequent patches, we add two more new versions of the syscalls (for pselect, ppoll and io_pgetevents) in addition to the existing native and compat versions. Adding such an api reduces the logic that would need to be replicated otherwise. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* signal: Add set_user_sigmask()Deepa Dinamani2018-12-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | Refactor reading sigset from userspace and updating sigmask into an api. This is useful for versions of syscalls that pass in the sigmask and expect the current->sigmask to be changed during, and restored after, the execution of the syscall. With the advent of new y2038 syscalls in the subsequent patches, we add two more new versions of the syscalls (for pselect, ppoll, and io_pgetevents) in addition to the existing native and compat versions. Adding such an api reduces the logic that would need to be replicated otherwise. Note that the calls to sigprocmask() ignored the return value from the api as the function only returns an error on an invalid first argument that is hardcoded at these call sites. The updated logic uses set_current_blocked() instead. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* include/linux/signal.h: mark expected switch fall-throughsGustavo A. R. Silva2018-10-311-0/+6
| | | | | | | | | | | | | | In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Link: http://lkml.kernel.org/r/20181013114847.GA3160@embeddedor.com Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Acked-by: Kees Cook <keescook@chromium.org> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signal: Guard against negative signal numbers in copy_siginfo_from_user32Eric W. Biederman2018-10-101-1/+1
| | | | | | | | | | | | | | | While fixing an out of bounds array access in known_siginfo_layout reported by the kernel test robot it became apparent that the same bug exists in siginfo_layout and affects copy_siginfo_from_user32. The straight forward fix that makes guards against making this mistake in the future and should keep the code size small is to just take an unsigned signal number instead of a signed signal number, as I did to fix known_siginfo_layout. Cc: stable@vger.kernel.org Fixes: cc731525f26a ("signal: Remove kernel interal si_code magic") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Use a smaller struct siginfo in the kernelEric W. Biederman2018-10-031-0/+2
| | | | | | | | | | | | | | | | | We reserve 128 bytes for struct siginfo but only use about 48 bytes on 64bit and 32 bytes on 32bit. Someday we might use more but it is unlikely to be anytime soon. Userspace seems content with just enough bytes of siginfo to implement sigqueue. Or in the case of checkpoint/restart reinjecting signals the kernel has sent. Reducing the stack footprint and the work to copy siginfo around from 2 cachelines to 1 cachelines seems worth doing even if I don't have benchmarks to show a performance difference. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Distinguish between kernel_siginfo and siginfoEric W. Biederman2018-10-031-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | Linus recently observed that if we did not worry about the padding member in struct siginfo it is only about 48 bytes, and 48 bytes is much nicer than 128 bytes for allocating on the stack and copying around in the kernel. The obvious thing of only adding the padding when userspace is including siginfo.h won't work as there are sigframe definitions in the kernel that embed struct siginfo. So split siginfo in two; kernel_siginfo and siginfo. Keeping the traditional name for the userspace definition. While the version that is used internally to the kernel and ultimately will not be padded to 128 bytes is called kernel_siginfo. The definition of struct kernel_siginfo I have put in include/signal_types.h A set of buildtime checks has been added to verify the two structures have the same field offsets. To make it easy to verify the change kernel_siginfo retains the same size as siginfo. The reduction in size comes in a following change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Introduce copy_siginfo_from_user and use it's return valueEric W. Biederman2018-10-031-0/+1
| | | | | | | | | | | | | | | In preparation for using a smaller version of siginfo in the kernel introduce copy_siginfo_from_user and use it when siginfo is copied from userspace. Make the pattern for using copy_siginfo_from_user and copy_siginfo_from_user32 to capture the return value and return that value on error. This is a necessary prerequisite for using a smaller siginfo in the kernel than the kernel exports to userspace. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2018-08-221-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge more updates from Andrew Morton: - the rest of MM - procfs updates - various misc things - more y2038 fixes - get_maintainer updates - lib/ updates - checkpatch updates - various epoll updates - autofs updates - hfsplus - some reiserfs work - fatfs updates - signal.c cleanups - ipc/ updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (166 commits) ipc/util.c: update return value of ipc_getref from int to bool ipc/util.c: further variable name cleanups ipc: simplify ipc initialization ipc: get rid of ids->tables_initialized hack lib/rhashtable: guarantee initial hashtable allocation lib/rhashtable: simplify bucket_table_alloc() ipc: drop ipc_lock() ipc/util.c: correct comment in ipc_obtain_object_check ipc: rename ipcctl_pre_down_nolock() ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid() ipc: reorganize initialization of kern_ipc_perm.seq ipc: compute kern_ipc_perm.id under the ipc lock init/Kconfig: remove EXPERT from CHECKPOINT_RESTORE fs/sysv/inode.c: use ktime_get_real_seconds() for superblock stamp adfs: use timespec64 for time conversion kernel/sysctl.c: fix typos in comments drivers/rapidio/devices/rio_mport_cdev.c: remove redundant pointer md fork: don't copy inconsistent signal handler state to child signal: make get_signal() return bool signal: make sigkill_pending() return bool ...
| * signal: make get_signal() return boolChristian Brauner2018-08-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | make get_signal() already behaves like a boolean function. Let's actually declare it as such too. Link: http://lkml.kernel.org/r/20180602103653.18181-18-christian@brauner.io Signed-off-by: Christian Brauner <christian@brauner.io> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: James Morris <james.morris@microsoft.com> Cc: Kees Cook <keescook@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * signal: make unhandled_signal() return boolChristian Brauner2018-08-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | unhandled_signal() already behaves like a boolean function. Let's actually declare it as such too. All callers treat it as such too. Link: http://lkml.kernel.org/r/20180602103653.18181-13-christian@brauner.io Signed-off-by: Christian Brauner <christian@brauner.io> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: James Morris <james.morris@microsoft.com> Cc: Kees Cook <keescook@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | signal: Pass pid type into do_send_sig_infoEric W. Biederman2018-07-211-1/+1
| | | | | | | | | | | | | | | | This passes the information we already have at the call sight into do_send_sig_info. Ultimately allowing for better handling of signals sent to a group of processes during fork. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | signal: Pass pid type into group_send_sig_infoEric W. Biederman2018-07-211-1/+3
|/ | | | | | | | This passes the information we already have at the call sight into group_send_sig_info. Ultimatelly allowing for to better handle signals sent to a group of processes. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR}Eric W. Biederman2018-04-261-0/+3
| | | | | | | | | | | | | | | | | | | Update the siginfo_layout function and enum siginfo_layout to represent all of the possible field layouts of struct siginfo. This allows the uses of siginfo_layout in um and arm64 where they are testing for SIL_FAULT to be more accurate as this rules out the other cases. Further this allows the switch statements on siginfo_layout to be simpler if perhaps a little more wordy. Making it easier to understand what is actually going on. As SIL_FAULT_BNDERR and SIL_FAULT_PKUERR are never expected to appear in signalfd just treat them as SIL_FAULT. To include them would take 20 extra bytes an pretty much fill up what is left of signalfd_siginfo. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Remove unnecessary ifdefs now that there is only one struct siginfoEric W. Biederman2018-01-121-2/+0
| | | | | | | Remove HAVE_ARCH_SIGINFO_T Remove __ARCH_SIGSYS Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Introduce clear_siginfoEric W. Biederman2018-01-121-0/+5
| | | | | | | | | | | | | | | Unfortunately struct siginfo has holes both in the common part of the structure, in the union members, and in the lack of padding of the union members. The result of those wholes is that the C standard does not guarantee those bits will be initialized. As struct siginfo is for communication between the kernel and userspace that is a problem. Add the helper function clear_siginfo that is guaranteed to clear all of the bits in struct siginfo so when the structure is copied there is no danger of copying old kernel data and causing a leak of information from kernel space to userspace. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signal: Reduce copy_siginfo to just a memcpyEric W. Biederman2018-01-121-6/+2
| | | | | | | | | | | | | | | The savings for copying just part of struct siginfo appears to be in the noise on modern machines. So remove this ``optimization'' and simplify the code. At the same time mark the second parameter as constant so there is no confusion as to which direction the copy will go. This ensures that a fully initialized siginfo that is sent ends up as a fully initialized siginfo on the signal queue. This full initialization ensures even confused code won't copy unitialized data to userspace, and it prepares for turning copy_siginfo_to_user into a simple copy_to_user. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* signal: Remove kernel interal si_code magicEric W. Biederman2017-07-241-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct siginfo is a union and the kernel since 2.4 has been hiding a union tag in the high 16bits of si_code using the values: __SI_KILL __SI_TIMER __SI_POLL __SI_FAULT __SI_CHLD __SI_RT __SI_MESGQ __SI_SYS While this looks plausible on the surface, in practice this situation has not worked well. - Injected positive signals are not copied to user space properly unless they have these magic high bits set. - Injected positive signals are not reported properly by signalfd unless they have these magic high bits set. - These kernel internal values leaked to userspace via ptrace_peek_siginfo - It was possible to inject these kernel internal values and cause the the kernel to misbehave. - Kernel developers got confused and expected these kernel internal values in userspace in kernel self tests. - Kernel developers got confused and set si_code to __SI_FAULT which is SI_USER in userspace which causes userspace to think an ordinary user sent the signal and that it was not kernel generated. - The values make it impossible to reorganize the code to transform siginfo_copy_to_user into a plain copy_to_user. As si_code must be massaged before being passed to userspace. So remove these kernel internal si codes and make the kernel code simpler and more maintainable. To replace these kernel internal magic si_codes introduce the helper function siginfo_layout, that takes a signal number and an si_code and computes which union member of siginfo is being used. Have siginfo_layout return an enumeration so that gcc will have enough information to warn if a switch statement does not handle all of union members. A couple of architectures have a messed up ABI that defines signal specific duplications of SI_USER which causes more special cases in siginfo_layout than I would like. The good news is only problem architectures pay the cost. Update all of the code that used the previous magic __SI_ values to use the new SIL_ values and to call siginfo_layout to get those values. Escept where not all of the cases are handled remove the defaults in the switch statements so that if a new case is missed in the future the lack will show up at compile time. Modify the code that copies siginfo si_code to userspace to just copy the value and not cast si_code to a short first. The high bits are no longer used to hold a magic union member. Fixup the siginfo header files to stop including the __SI_ values in their constants and for the headers that were missing it to properly update the number of si_codes for each signal type. The fixes to copy_siginfo_from_user32 implementations has the interesting property that several of them perviously should never have worked as the __SI_ values they depended up where kernel internal. With that dependency gone those implementations should work much better. The idea of not passing the __SI_ values out to userspace and then not reinserting them has been tested with criu and criu worked without changes. Ref: 2.4.0-test1 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* fcntl: Don't use ambiguous SIG_POLL si_codesEric W. Biederman2017-07-241-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a weird and problematic intersection of features that when they all come together result in ambiguous siginfo values, that we can not support properly. - Supporting fcntl(F_SETSIG,...) with arbitrary valid signals. - Using positive values for POLL_IN, POLL_OUT, POLL_MSG, ..., etc that imply they are signal specific si_codes and using the aforementioned arbitrary signal to deliver them. - Supporting injection of arbitrary siginfo values for debugging and checkpoint/restore. The result is that just looking at siginfo si_codes of 1 to 6 are ambigious. It could either be a signal specific si_code or it could be a generic si_code. For most of the kernel this is a non-issue but for sending signals with siginfo it is impossible to play back the kernel signals and get the same result. Strictly speaking when the si_code was changed from SI_SIGIO to POLL_IN and friends between 2.2 and 2.4 this functionality was not ambiguous, as only real time signals were supported. Before 2.4 was released the kernel began supporting siginfo with non realtime signals so they could give details of why the signal was sent. The result is that if F_SETSIG is set to one of the signals with signal specific si_codes then user space can not know why the signal was sent. I grepped through a bunch of userspace programs using debian code search to get a feel for how often people choose a signal that results in an ambiguous si_code. I only found one program doing so and it was using SIGCHLD to test the F_SETSIG functionality, and did not appear to be a real world usage. Therefore the ambiguity does not appears to be a real world problem in practice. Remove the ambiguity while introducing the smallest chance of breakage by changing the si_code to SI_SIGIO when signals with signal specific si_codes are targeted. Fixes: v2.3.40 -- Added support for queueing non-rt signals Fixes: v2.3.21 -- Changed the si_code from SI_SIGIO Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* Merge branch 'misc.compat' of ↵Linus Torvalds2017-07-061-2/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc compat stuff updates from Al Viro: "This part is basically untangling various compat stuff. Compat syscalls moved to their native counterparts, getting rid of quite a bit of double-copying and/or set_fs() uses. A lot of field-by-field copyin/copyout killed off. - kernel/compat.c is much closer to containing just the copyin/copyout of compat structs. Not all compat syscalls are gone from it yet, but it's getting there. - ipc/compat_mq.c killed off completely. - block/compat_ioctl.c cleaned up; floppy compat ioctls moved to drivers/block/floppy.c where they belong. Yes, there are several drivers that implement some of the same ioctls. Some are m68k and one is 32bit-only pmac. drivers/block/floppy.c is the only one in that bunch that can be built on biarch" * 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: mqueue: move compat syscalls to native ones usbdevfs: get rid of field-by-field copyin compat_hdio_ioctl: get rid of set_fs() take floppy compat ioctls to sodding floppy.c ipmi: get rid of field-by-field __get_user() ipmi: get COMPAT_IPMICTL_RECEIVE_MSG in sync with the native one rt_sigtimedwait(): move compat to native select: switch compat_{get,put}_fd_set() to compat_{get,put}_bitmap() put_compat_rusage(): switch to copy_to_user() sigpending(): move compat to native getrlimit()/setrlimit(): move compat to native times(2): move compat to native compat_{get,put}_bitmap(): use unsafe_{get,put}_user() fb_get_fscreeninfo(): don't bother with do_fb_ioctl() do_sigaltstack(): lift copying to/from userland into callers take compat_sys_old_getrlimit() to native syscall trim __ARCH_WANT_SYS_OLD_GETRLIMIT
| * rt_sigtimedwait(): move compat to nativeAl Viro2017-06-091-2/+0
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | signal: Move copy_siginfo_to_user to <linux/signal.h>Christoph Hellwig2017-06-041-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Having it in asm-generic/siginfo.h doesn't make any sense as it is in no way architecture specific. Move it to signal.h instead where several related functions already reside. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-ia64@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: sparclinux@vger.kernel.org Cc: "David S. Miller" <davem@davemloft.net> Link: http://lkml.kernel.org/r/20170603190102.28866-5-hch@lst.de
* | ia64: Remove HAVE_ARCH_COPY_SIGINFOChristoph Hellwig2017-06-041-6/+1
|/ | | | | | | | | | | | | | | | | | | | Since ia64 defines __ARCH_SI_PREAMBLE_SIZE it can just use the generic copy_siginfo implementation, which is identical to the architecture specific one. With that support for HAVE_ARCH_COPY_SIGINFO can go away entirely. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-ia64@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: sparclinux@vger.kernel.org Cc: "David S. Miller" <davem@davemloft.net> Link: http://lkml.kernel.org/r/20170603190102.28866-3-hch@lst.de
* signal: Remove unused definition of sig_user_definiedEric W. Biederman2017-04-171-4/+0
| | | | Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* signals: Move signal data types from <linux/signal.h> to <linux/signal_types.h>Ingo Molnar2017-03-031-54/+0
| | | | | | | | | | | | Separate out just the pure data types - sched.h will be able to use this reduced size header. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* signals: Prepare to split out <linux/signal_types.h> from <linux/signal.h>Ingo Molnar2017-03-021-2/+1
| | | | | | | | | | | Introduce dummy header and add dependencies to places that will depend on it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* signals: avoid unnecessary taking of sighand->siglockWaiman Long2016-12-141-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When running certain database workload on a high-end system with many CPUs, it was found that spinlock contention in the sigprocmask syscalls became a significant portion of the overall CPU cycles as shown below. 9.30% 9.30% 905387 dataserver /proc/kcore 0x7fff8163f4d2 [k] _raw_spin_lock_irq | ---_raw_spin_lock_irq | |--99.34%-- __set_current_blocked | sigprocmask | sys_rt_sigprocmask | system_call_fastpath | | | |--50.63%-- __swapcontext | | | | | |--99.91%-- upsleepgeneric | | | |--49.36%-- __setcontext | | ktskRun Looking further into the swapcontext function in glibc, it was found that the function always call sigprocmask() without checking if there are changes in the signal mask. A check was added to the __set_current_blocked() function to avoid taking the sighand->siglock spinlock if there is no change in the signal mask. This will prevent unneeded spinlock contention when many threads are trying to call sigprocmask(). With this patch applied, the spinlock contention in sigprocmask() was gone. Link: http://lkml.kernel.org/r/1474979209-11867-1-git-send-email-Waiman.Long@hpe.com Signed-off-by: Waiman Long <Waiman.Long@hpe.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Stas Sergeev <stsp@list.ru> Cc: Scott J Norton <scott.norton@hpe.com> Cc: Douglas Hatch <doug.hatch@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signal: move the "sig < SIGRTMIN" check into siginmask(sig)Oleg Nesterov2016-05-231-9/+7
| | | | | | | | | | | | | | | | | All the users of siginmask() must ensure that sig < SIGRTMIN. sig_fatal() doesn't and this is wrong: UBSAN: Undefined behaviour in kernel/signal.c:911:6 shift exponent 32 is too large for 32-bit type 'long unsigned int' the patch doesn't add the neccesary check to sig_fatal(), it moves the check into siginmask() and updates other callers. Link: http://lkml.kernel.org/r/20160517195052.GA15187@redhat.com Reported-by: Meelis Roos <mroos@linux.ee> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linusLinus Torvalds2016-05-191-0/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull MIPS updates from Ralf Baechle: "This is the main pull request for MIPS for 4.7. Here's the summary of the changes: - ATH79: Support for DTB passuing using the UHI boot protocol - ATH79: Remove support for builtin DTB. - ATH79: Add zboot debug serial support. - ATH79: Add initial support for Dragino MS14 (Dragine 2), Onion Omega and DPT-Module. - ATH79: Update devicetree clock support for AR9132 and AR9331. - ATH79: Cleanup the DT code. - ATH79: Support newer SOCs in ath79_ddr_ctrl_init. - ATH79: Fix regression in PCI window initialization. - BCM47xx: Move SPROM driver to drivers/firmware/ - BCM63xx: Enable partition parser in defconfig. - BMIPS: BMIPS5000 has I cache filing from D cache - BMIPS: BMIPS: Add cpu-feature-overrides.h - BMIPS: Add Whirlwind support - BMIPS: Adjust mips-hpt-frequency for BCM7435 - BMIPS: Remove maxcpus from BCM97435SVMB DTS - BMIPS: Add missing 7038 L1 register cells to BCM7435 - BMIPS: Various tweaks to initialization code. - BMIPS: Enable partition parser in defconfig. - BMIPS: Cache tweaks. - BMIPS: Add UART, I2C and SATA devices to DT. - BMIPS: Add BCM6358 and BCM63268support - BMIPS: Add device tree example for BCM6358. - BMIPS: Improve Improve BCM6328 and BCM6368 device trees - Lantiq: Add support for device tree file from boot loader - Lantiq: Allow build with no built-in DT. - Loongson 3: Reserve 32MB for RS780E integrated GPU. - Loongson 3: Fix build error after ld-version.sh modification - Loongson 3: Move chipset ACPI code from drivers to arch. - Loongson 3: Speedup irq processing. - Loongson 3: Add basic Loongson 3A support. - Loongson 3: Set cache flush handlers to nop. - Loongson 3: Invalidate special TLBs when needed. - Loongson 3: Fast TLB refill handler. - MT7620: Fallback strategy for invalid syscfg0. - Netlogic: Fix CP0_EBASE redefinition warnings - Octeon: Initialization fixes - Octeon: Add DTS files for the D-Link DSR-1000N and EdgeRouter Lite - Octeon: Enable add Octeon-drivers in cavium_octeon_defconfig - Octeon: Correctly handle endian-swapped initramfs images. - Octeon: Support CN73xx, CN75xx and CN78xx. - Octeon: Remove dead code from cvmx-sysinfo. - Octeon: Extend number of supported CPUs past 32. - Octeon: Remove some code limiting NR_IRQS to 255. - Octeon: Simplify octeon_irq_ciu_gpio_set_type. - Octeon: Mark some functions __init in smp.c - Octeon: Octeon: Add Octeon III CN7xxx interface detection - PIC32: Add serial driver and bindings for it. - PIC32: Add PIC32 deadman timer driver and bindings. - PIC32: Add PIC32 clock timer driver and bindings. - Pistachio: Determine SoC revision during boot - Sibyte: Fix Kconfig dependencies of SIBYTE_BUS_WATCHER. - Sibyte: Strip redundant comments from bcm1480_regs.h. - Panic immediately if panic_on_oops is set. - module: fix incorrect IS_ERR_VALUE macro usage. - module: Make consistent use of pr_* - Remove no longer needed work_on_cpu() call. - Remove CONFIG_IPV6_PRIVACY from defconfigs. - Fix registers of non-crashing CPUs in dumps. - Handle MIPSisms in new vmcore_elf32_check_arch. - Select CONFIG_HANDLE_DOMAIN_IRQ and make it work. - Allow RIXI to be used on non-R2 or R6 cores. - Reserve nosave data for hibernation - Fix siginfo.h to use strict POSIX types. - Don't unwind user mode with EVA. - Fix watchpoint restoration - Ptrace watchpoints for R6. - Sync icache when it fills from dcache - I6400 I-cache fills from dcache. - Various MSA fixes. - Cleanup MIPS_CPU_* definitions. - Signal: Move generic copy_siginfo to signal.h - Signal: Fix uapi include in exported asm/siginfo.h - Timer fixes for sake of KVM. - XPA TLB refill fixes. - Treat perf counter feature - Update John Crispin's email address - Add PIC32 watchdog and bindings. - Handle R10000 LL/SC bug in set_pte() - cpufreq: Various fixes for Longson1. - R6: Fix R2 emulation. - mathemu: Cosmetic fix to ADDIUPC emulation, plenty of other small fixes - ELF: ABI and FP fixes. - Allow for relocatable kernel and use that to support KASLR. - Fix CPC_BASE_ADDR mask - Plenty fo smp-cps, CM, R6 and M6250 fixes. - Make reset_control_ops const. - Fix kernel command line handling of leading whitespace. - Cleanups to cache handling. - Add brcm, bcm6345-l1-intc device tree bindings. - Use generic clkdev.h header - Remove CLK_IS_ROOT usage. - Misc small cleanups. - CM: Fix compilation error when !MIPS_CM - oprofile: Fix a preemption issue - Detect DSP ASE v3 support:1" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (275 commits) MIPS: pic32mzda: fix getting timer clock rate. MIPS: ath79: fix regression in PCI window initialization MIPS: ath79: make ath79_ddr_ctrl_init() compatible for newer SoCs MIPS: Fix VZ probe gas errors with binutils <2.24 MIPS: perf: Fix I6400 event numbers MIPS: DEC: Export `ioasic_ssr_lock' to modules MIPS: MSA: Fix a link error on `_init_msa_upper' with older GCC MIPS: CM: Fix compilation error when !MIPS_CM MIPS: Fix genvdso error on rebuild USB: ohci-jz4740: Remove obsolete driver MIPS: JZ4740: Probe OHCI platform device via DT MIPS: JZ4740: Qi LB60: Remove support for AVT2 variant MIPS: pistachio: Determine SoC revision during boot MIPS: BMIPS: Adjust mips-hpt-frequency for BCM7435 mips: mt7620: fallback to SDRAM when syscfg0 does not have a valid value for the memory type MIPS: Prevent "restoration" of MSA context in non-MSA kernels MIPS: cevt-r4k: Dynamically calculate min_delta_ns MIPS: malta-time: Take seconds into account MIPS: malta-time: Start GIC count before syncing to RTC MIPS: Force CPUs to lose FP context during mode switches ...
| * SIGNAL: Move generic copy_siginfo() to signal.hJames Hogan2016-05-131-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The generic copy_siginfo() is currently defined in asm-generic/siginfo.h, after including uapi/asm-generic/siginfo.h which defines the generic struct siginfo. However this makes it awkward for an architecture to use it if it has to define its own struct siginfo (e.g. MIPS and potentially IA64), since it means that asm-generic/siginfo.h can only be included after defining the arch-specific siginfo, which may be problematic if the arch-specific definition needs definitions from uapi/asm-generic/siginfo.h. It is possible to work around this by first including uapi/asm-generic/siginfo.h to get the constants before defining the arch-specific siginfo, and include asm-generic/siginfo.h after. However uapi headers can't be included by other uapi headers, so that first include has to be in an ifdef __kernel__, with the non __kernel__ case including the non-UAPI header instead. Instead of that mess, move the generic copy_siginfo() definition into linux/signal.h, which allows an arch-specific uapi/asm/siginfo.h to include asm-generic/siginfo.h and define the arch-specific siginfo, and for the generic copy_siginfo() to see that arch-specific definition. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Petr Malat <oss@malat.biz> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Christopher Ferris <cferris@google.com> Cc: linux-arch@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-ia64@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: <stable@vger.kernel.org> # 4.0- Patchwork: https://patchwork.linux-mips.org/patch/12478/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>