From 3aa416b07f0adf01c090baab26fb70c35ec17623 Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Thu, 11 Oct 2007 22:11:11 +0200 Subject: lockdep: fix mismatched lockdep_depth/curr_chain_hash It is possible for the current->curr_chain_key to become inconsistent with the current index if the chain fails to validate. The end result is that future lock_acquire() operations may inadvertently fail to find a hit in the cache resulting in a new node being added to the graph for every acquire. Signed-off-by: Gregory Haskins Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel/lockdep.c') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 734da579ad1..42ae4a5ab4d 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1521,7 +1521,7 @@ cache_hit: } static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, - struct held_lock *hlock, int chain_head) + struct held_lock *hlock, int chain_head, u64 chain_key) { /* * Trylock needs to maintain the stack of held locks, but it @@ -1534,7 +1534,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, * graph_lock for us) */ if (!hlock->trylock && (hlock->check == 2) && - lookup_chain_cache(curr->curr_chain_key, hlock->class)) { + lookup_chain_cache(chain_key, hlock->class)) { /* * Check whether last held lock: * @@ -1576,7 +1576,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, #else static inline int validate_chain(struct task_struct *curr, struct lockdep_map *lock, struct held_lock *hlock, - int chain_head) + int chain_head, u64 chain_key) { return 1; } @@ -2450,11 +2450,11 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, chain_head = 1; } chain_key = iterate_chain_key(chain_key, id); - curr->curr_chain_key = chain_key; - if (!validate_chain(curr, lock, hlock, chain_head)) + if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) return 0; + curr->curr_chain_key = chain_key; curr->lockdep_depth++; check_chain_key(curr); #ifdef CONFIG_DEBUG_LOCKDEP -- cgit v1.2.3-18-g5258 From b351d164e860d1ffffdc501c32f55dd1446c385b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 11 Oct 2007 22:11:12 +0200 Subject: lockdep: syscall exit check Provide a check to validate that we do not hold any locks when switching back to user-space. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/lockdep.c') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 42ae4a5ab4d..a6f1ee9c92d 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3199,3 +3199,19 @@ void debug_show_held_locks(struct task_struct *task) } EXPORT_SYMBOL_GPL(debug_show_held_locks); + +void lockdep_sys_exit(void) +{ + struct task_struct *curr = current; + + if (unlikely(curr->lockdep_depth)) { + if (!debug_locks_off()) + return; + printk("\n================================================\n"); + printk( "[ BUG: lock held when returning to user space! ]\n"); + printk( "------------------------------------------------\n"); + printk("%s/%d is leaving the kernel with locks still held!\n", + curr->comm, curr->pid); + lockdep_print_held_locks(curr); + } +} -- cgit v1.2.3-18-g5258