diff options
author | Boqun Feng <boqun.feng@gmail.com> | 2020-08-07 15:42:20 +0800 |
---|---|---|
committer | Peter Zijlstra <peterz@infradead.org> | 2020-08-26 12:42:02 +0200 |
commit | e918188611f073063415f40fae568fa4d86d9044 (patch) | |
tree | 360f04ba1aeae14a4205a2b74ce0f5090bf70378 /kernel/locking/lockdep.c | |
parent | 92b4e9f11a636d1723cc0866bf8b9111b1e24339 (diff) |
locking: More accurate annotations for read_lock()
On the archs using QUEUED_RWLOCKS, read_lock() is not always a recursive
read lock, actually it's only recursive if in_interrupt() is true. So
change the annotation accordingly to catch more deadlocks.
Note we used to treat read_lock() as pure recursive read locks in
lib/locking-seftest.c, and this is useful, especially for the lockdep
development selftest, so we keep this via a variable to force switching
lock annotation for read_lock().
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-2-boqun.feng@gmail.com
Diffstat (limited to 'kernel/locking/lockdep.c')
-rw-r--r-- | kernel/locking/lockdep.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 54b74fabf40c..77cd9e6520c4 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4968,6 +4968,20 @@ static bool lockdep_nmi(void) } /* + * read_lock() is recursive if: + * 1. We force lockdep think this way in selftests or + * 2. The implementation is not queued read/write lock or + * 3. The locker is at an in_interrupt() context. + */ +bool read_lock_is_recursive(void) +{ + return force_read_lock_recursive || + !IS_ENABLED(CONFIG_QUEUED_RWLOCKS) || + in_interrupt(); +} +EXPORT_SYMBOL_GPL(read_lock_is_recursive); + +/* * We are not always called with irqs disabled - do that here, * and also avoid lockdep recursion: */ |