From 95bfdf23e4d59099340c01064f39e7f6875c02bc Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Mon, 8 Dec 2014 14:07:59 +0300 Subject: tools/liblockdep: Fix debug_check thinko in mutex destroy In mutex destroy code currently we pass to debug_check_no_locks_freed() [mem_from, mem_end) address region. But debug_check_no_locks_freed() accepts mem_from, mem_*len* i.e. second parameter is region length, not end address. And it was always so, starting from 2006 (fbb9ce95 "lockdep: core"). Fix it, or else on a mutex destroy we wrongly check much-wider-than-mutex region and can find not-yet-released other locks there and wrongly report BUGs on them. Signed-off-by: Kirill Smelkov Signed-off-by: Sasha Levin diff --git a/tools/lib/lockdep/preload.c b/tools/lib/lockdep/preload.c index 6f80360..0b0112c 100644 --- a/tools/lib/lockdep/preload.c +++ b/tools/lib/lockdep/preload.c @@ -317,7 +317,7 @@ int pthread_mutex_destroy(pthread_mutex_t *mutex) * * TODO: Hook into free() and add that check there as well. */ - debug_check_no_locks_freed(mutex, mutex + sizeof(*mutex)); + debug_check_no_locks_freed(mutex, sizeof(*mutex)); __del_lock(__get_lock(mutex)); return ll_pthread_mutex_destroy(mutex); } @@ -341,7 +341,7 @@ int pthread_rwlock_destroy(pthread_rwlock_t *rwlock) { try_init_preload(); - debug_check_no_locks_freed(rwlock, rwlock + sizeof(*rwlock)); + debug_check_no_locks_freed(rwlock, sizeof(*rwlock)); __del_lock(__get_lock(rwlock)); return ll_pthread_rwlock_destroy(rwlock); } -- cgit v0.10.2 From a63b03e2d2477586440741677ecac45bcf28d7b1 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 6 Jan 2015 10:29:35 +0000 Subject: mutex: Always clear owner field upon mutex_unlock() Currently if DEBUG_MUTEXES is enabled, the mutex->owner field is only cleared iff debug_locks is active. This exposes a race to other users of the field where the mutex->owner may be still set to a stale value, potentially upsetting mutex_spin_on_owner() among others. References: https://bugs.freedesktop.org/show_bug.cgi?id=87955 Signed-off-by: Chris Wilson Signed-off-by: Peter Zijlstra (Intel) Acked-by: Davidlohr Bueso Cc: Daniel Vetter Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1420540175-30204-1-git-send-email-chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c index 5cf6731..3ef3736 100644 --- a/kernel/locking/mutex-debug.c +++ b/kernel/locking/mutex-debug.c @@ -80,13 +80,13 @@ void debug_mutex_unlock(struct mutex *lock) DEBUG_LOCKS_WARN_ON(lock->owner != current); DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next); - mutex_clear_owner(lock); } /* * __mutex_slowpath_needs_to_unlock() is explicitly 0 for debug * mutexes so that we can do it here after we've verified state. */ + mutex_clear_owner(lock); atomic_set(&lock->count, 1); } -- cgit v0.10.2