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 <[email protected]> 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) <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Ingo Molnar <[email protected]>
