]> git.karo-electronics.de Git - karo-tx-linux.git/commit
lglock: update lockdep annotations to report recursive local locks
authorMichel Lespinasse <walken@google.com>
Wed, 19 Jun 2013 00:05:41 +0000 (10:05 +1000)
committerStephen Rothwell <sfr@canb.auug.org.au>
Wed, 19 Jun 2013 07:12:49 +0000 (17:12 +1000)
commit6c7d3b939d38131ec7684b7d4fb996cbc1f47f93
tree51e1df6da9b956b59fc77d6864e0b3827c755f4f
parent3a719e0fbb248b95cfa1baf9dcecfa7a4161a5ec
lglock: update lockdep annotations to report recursive local locks

Oleg Nesterov recently noticed that the lockdep annotations in lglock.c
are not sufficient to detect some obvious deadlocks, such as
lg_local_lock(LOCK) + lg_local_lock(LOCK) or spin_lock(X) +
lg_local_lock(Y) vs lg_local_lock(Y) + spin_lock(X).

Both issues are easily fixed by indicating to lockdep that lglock's local
locks are not recursive.  We shouldn't use the rwlock acquire/release
functions here, as lglock doesn't share the same semantics.  Instead we
can base our lockdep annotations on the lock_acquire_shared (for local
lglock) and lock_acquire_exclusive (for global lglock) helpers.

I am not proposing new lglock specific helpers as I don't see the point of
the existing second level of helpers :)

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kernel/lglock.c