kernel/linux.git/include/linux/spinlock.h, branch v6.6.132

cleanup: Add conditional guard support

2025-01-09T12:31:41+00:00

[ Upstream commit e4ab322fbaaaf84b23d6cb0e3317a7f68baf36dc ] Adds: - DEFINE_GUARD_COND() / DEFINE_LOCK_GUARD_1_COND() to extend existing guards with conditional lock primitives, eg. mutex_trylock(), mutex_lock_interruptible(). nb. both primitives allow NULL 'locks', which cause the lock to fail (obviously). - extends scoped_guard() to not take the body when the the conditional guard 'fails'. eg. scoped_guard (mutex_intr, &task->signal_cred_guard_mutex) { ... } will only execute the body when the mutex is held. - provides scoped_cond_guard(name, fail, args...); which extends scoped_guard() to do fail when the lock-acquire fails. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20231102110706.460851167%40infradead.org Stable-dep-of: fcc22ac5baf0 ("cleanup: Adjust scoped_guard() macros to avoid potential warning") Signed-off-by: Sasha Levin

locking: Introduce __cleanup() based infrastructure

2023-06-26T09:14:18+00:00

Use __attribute__((__cleanup__(func))) to build: - simple auto-release pointers using __free() - 'classes' with constructor and destructor semantics for scope-based resource management. - lock guards based on the above classes. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20230612093537.614161713%40infradead.org

perf: Fix perf_event_pmu_context serialization

2023-01-31T19:37:18+00:00

Syzkaller triggered a WARN in put_pmu_ctx(). WARNING: CPU: 1 PID: 2245 at kernel/events/core.c:4925 put_pmu_ctx+0x1f0/0x278 This is because there is no locking around the access of "if (!epc->ctx)" in find_get_pmu_context() and when it is set to NULL in put_pmu_ctx(). The decrement of the reference count in put_pmu_ctx() also happens outside of the spinlock, leading to the possibility of this order of events, and the context being cleared in put_pmu_ctx(), after its refcount is non zero: CPU0 CPU1 find_get_pmu_context() if (!epc->ctx) == false put_pmu_ctx() atomic_dec_and_test(&epc->refcount) == true epc->refcount == 0 atomic_inc(&epc->refcount); epc->refcount == 1 list_del_init(&epc->pmu_ctx_entry); epc->ctx = NULL; Another issue is that WARN_ON for no active PMU events in put_pmu_ctx() is outside of the lock. If the perf_event_pmu_context is an embedded one, even after clearing it, it won't be deleted and can be re-used. So the warning can trigger. For this reason it also needs to be moved inside the lock. The above warning is very quick to trigger on Arm by running these two commands at the same time: while true; do perf record -- ls; done while true; do perf record -- ls; done [peterz: atomic_dec_and_raw_lock*()] Fixes: bd2756811766 ("perf: Rewrite core context handling") Reported-by: syzbot+697196bc0265049822bd@syzkaller.appspotmail.com Signed-off-by: James Clark Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Ravi Bangoria Link: https://lore.kernel.org/r/20230127143141.1782804-2-james.clark@arm.com

locking: Detect includes rwlock.h outside of spinlock.h

2022-09-15T14:14:02+00:00

From: Michael S. Tsirkin The check for __LINUX_SPINLOCK_H within rwlock.h (and other files) detects the direct include of the header file if it is at the very beginning of the include section. If it is listed later then chances are high that spinlock.h was already included (including rwlock.h) and the additional listing of rwlock.h will not cause any failure. On PREEMPT_RT this additional rwlock.h will lead to compile failures since it uses a different rwlock implementation. Add __LINUX_INSIDE_SPINLOCK_H to spinlock.h and check for this instead of __LINUX_SPINLOCK_H to detect wrong includes. This will help detect direct includes of rwlock.h with without PREEMPT_RT enabled. [ bigeasy: add remaining __LINUX_SPINLOCK_H user and rewrite commit description. ] Signed-off-by: Michael S. Tsirkin Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/YweemHxJx7O8rjBx@linutronix.de

locking/barriers, kcsan: Add instrumentation for barriers

2021-12-10T00:42:27+00:00

Adds the required KCSAN instrumentation for barriers if CONFIG_SMP. KCSAN supports modeling the effects of: smp_mb() smp_rmb() smp_wmb() smp_store_release() Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

Merge branch 'akpm' (patches from Andrew)

2021-11-09T18:11:53+00:00

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 : (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 ...

kernel.h: drop unneeded inclusion from other headers

2021-11-09T18:02:49+00:00

Patch series "kernel.h further split", v5. kernel.h is a set of something which is not related to each other and often used in non-crossed compilation units, especially when drivers need only one or two macro definitions from it. This patch (of 7): There is no evidence we need kernel.h inclusion in certain headers. Drop unneeded inclusion from other headers. [sfr@canb.auug.org.au: bottom_half.h needs kernel] Link: https://lkml.kernel.org/r/20211015202908.1c417ae2@canb.auug.org.au Link: https://lkml.kernel.org/r/20211013170417.87909-1-andriy.shevchenko@linux.intel.com Link: https://lkml.kernel.org/r/20211013170417.87909-2-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Signed-off-by: Stephen Rothwell Cc: Thomas Gleixner Cc: Brendan Higgins Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng Cc: Sakari Ailus Cc: Laurent Pinchart Cc: Mauro Carvalho Chehab Cc: Miguel Ojeda Cc: Jonathan Cameron Cc: Rasmus Villemoes Cc: Thorsten Leemhuis Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

locking: Remove spin_lock_flags() etc

2021-10-30T14:37:28+00:00

parisc, ia64 and powerpc32 are the only remaining architectures that provide custom arch_{spin,read,write}_lock_flags() functions, which are meant to re-enable interrupts while waiting for a spinlock. However, none of these can actually run into this codepath, because it is only called on architectures without CONFIG_GENERIC_LOCKBREAK, or when CONFIG_DEBUG_LOCK_ALLOC is set without CONFIG_LOCKDEP, and none of those combinations are possible on the three architectures. Going back in the git history, it appears that arch/mn10300 may have been able to run into this code path, but there is a good chance that it never worked. On the architectures that still exist, it was already impossible to hit back in 2008 after the introduction of CONFIG_GENERIC_LOCKBREAK, and possibly earlier. As this is all dead code, just remove it and the helper functions built around it. For arch/ia64, the inline asm could be cleaned up, but it seems safer to leave it untouched. Signed-off-by: Arnd Bergmann Signed-off-by: Peter Zijlstra (Intel) Acked-by: Helge Deller # parisc Link: https://lore.kernel.org/r/20211022120058.1031690-1-arnd@kernel.org

locking/spinlock: Provide RT variant header:

2021-08-17T15:43:24+00:00

Provide the necessary wrappers around the actual rtmutex based spinlock implementation. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210815211303.712897671@linutronix.de

locking/spinlock: Split the lock types header, and move the raw types into

2021-08-17T15:26:27+00:00

Move raw_spinlock into its own file. Prepare for RT 'sleeping spinlocks', to avoid header recursion, as RT locks require rtmutex.h, which in turn requires the raw spinlock types. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210815211303.371269088@linutronix.de