* Locking API testsuite: mixed read-lock/lock-write ABBA: |FAILED|
@ 2017-10-11 18:28 Jakub Kicinski
2017-10-11 18:50 ` Peter Zijlstra
0 siblings, 1 reply; 2+ messages in thread
From: Jakub Kicinski @ 2017-10-11 18:28 UTC (permalink / raw)
To: LKML; +Cc: Peter Zijlstra, Ingo Molnar
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?
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Locking API testsuite: mixed read-lock/lock-write ABBA: |FAILED|
2017-10-11 18:28 Locking API testsuite: mixed read-lock/lock-write ABBA: |FAILED| Jakub Kicinski
@ 2017-10-11 18:50 ` Peter Zijlstra
0 siblings, 0 replies; 2+ messages in thread
From: Peter Zijlstra @ 2017-10-11 18:50 UTC (permalink / raw)
To: Jakub Kicinski; +Cc: LKML, Ingo Molnar
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>
^ permalink raw reply [flat|nested] 2+ messages in thread
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