Messages in this thread | | | Subject | Re: [PATCH 1/8] lockdep: fix recursive read lock validation | From | Peter Zijlstra <> | Date | Tue, 29 Apr 2008 16:57:30 +0200 |
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On Tue, 2008-04-29 at 15:16 +0200, Bart Van Assche wrote: > On Tue, Apr 29, 2008 at 2:57 PM, Gautham R Shenoy <ego@in.ibm.com> wrote: > > Subject: lockdep: fix recursive read lock validation > > This means that the following sequence is now invalid, whereas previously > > it was considered valid: > > > > rlock(a); rlock(b); runlock(b); runlock(a) > > rlock(b); rlock(a); > > Why are you marking this sequence as invalid ? Although it can be > debated whether it is good programming practice to be inconsistent > about the order of read-locking, the above sequence can't be involved > in a deadlock.
Not for pure read locks, but when you add write locks to it, it does get deadlocky. Lockdep does not keep separate chains for read and write locks.
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