Messages in this thread | | | Date | Wed, 11 Oct 2017 20:50:14 +0200 | From | Peter Zijlstra <> | Subject | Re: Locking API testsuite: mixed read-lock/lock-write ABBA: |FAILED| |
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On Wed, Oct 11, 2017 at 11:28:25AM -0700, Jakub Kicinski wrote: > I'm seeing a failure on net-next kernels (rc4): > > [ 0.000000] -------------------------------------------------------------------------- > [ 0.000000] recursive read-lock: | ok | | ok | > [ 0.000000] recursive read-lock #2: | ok | | ok | > [ 0.000000] mixed read-write-lock: | ok | | ok | > [ 0.000000] mixed write-read-lock: | ok | | ok | > [ 0.000000] mixed read-lock/lock-write ABBA: |FAILED| | ok | > [ 0.000000] mixed read-lock/lock-read ABBA: | ok | | ok | > [ 0.000000] mixed write-lock/lock-write ABBA: | ok | | ok | > [ 0.000000] -------------------------------------------------------------------------- > > Is this OK?
Yes,
commit e91498589746065e3ae95d9a00b068e525eec34f Author: Peter Zijlstra <peterz@infradead.org> Date: Wed Aug 23 13:13:11 2017 +0200
locking/lockdep/selftests: Add mixed read-write ABBA tests
Currently lockdep has limited support for recursive readers, add a few mixed read-write ABBA selftests to show the extend of these limitations.
[ 0.000000] ---------------------------------------------------------------------------- [ 0.000000] | spin |wlock |rlock |mutex | wsem | rsem | [ 0.000000] -------------------------------------------------------------------------- [ 0.000000] mixed read-lock/lock-write ABBA: |FAILED| | ok | [ 0.000000] mixed read-lock/lock-read ABBA: | ok | | ok | [ 0.000000] mixed write-lock/lock-write ABBA: | ok | | ok | This clearly illustrates the case where lockdep fails to find a deadlock. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: boqun.feng@gmail.com Cc: byungchul.park@lge.com Cc: david@fromorbit.com Cc: johannes@sipsolutions.net Cc: oleg@redhat.com Cc: tj@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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