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 <pet...@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) <pet...@infradead.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: boqun.f...@gmail.com
Cc: byungchul.p...@lge.com
Cc: da...@fromorbit.com
Cc: johan...@sipsolutions.net
Cc: o...@redhat.com
Cc: t...@kernel.org
Signed-off-by: Ingo Molnar <mi...@kernel.org>
