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| author | Johannes Berg <johannes@sipsolutions.net> | 2007-10-18 23:39:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 11:53:38 -0700 |
| commit | 4e6045f134784f4b158b3c0f7a282b04bd816887 (patch) | |
| tree | 3304628f666c8524accd10f40da48cfba8b08608 /kernel/lockdep.c | |
| parent | cf7b708c8d1d7a27736771bcf4c457b332b0f818 (diff) | |
| download | lwn-4e6045f134784f4b158b3c0f7a282b04bd816887.tar.gz lwn-4e6045f134784f4b158b3c0f7a282b04bd816887.zip | |
workqueue: debug flushing deadlocks with lockdep
In the following scenario:
code path 1:
my_function() -> lock(L1); ...; flush_workqueue(); ...
code path 2:
run_workqueue() -> my_work() -> ...; lock(L1); ...
you can get a deadlock when my_work() is queued or running
but my_function() has acquired L1 already.
This patch adds a pseudo-lock to each workqueue to make lockdep
warn about this scenario.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/lockdep.c')
| -rw-r--r-- | kernel/lockdep.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index a6f1ee9c92d9..b5392ff7e6a6 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, u64 chain_key) + struct held_lock *hlock, int chain_head, u64 chain_key) { /* * Trylock needs to maintain the stack of held locks, but it |