On 08/17/2017 07:23 PM, Steven Rostedt wrote: > On Thu, 17 Aug 2017 18:18:18 -0400 > Steven Rostedt <rost...@goodmis.org> wrote: > >> On Thu, 17 Aug 2017 18:13:20 -0400 >> Steven Rostedt <rost...@goodmis.org> wrote: >> >>> On Thu, 17 Aug 2017 17:27:22 -0400 >>> Waiman Long <long...@redhat.com> wrote: >>> >>> >>>> It is actually what the patch is trying to do by checking for the >>>> deletion flag in the mutex_trylock loop. Please note that mutex does not >>>> guarantee FIFO ordering of lock acquisition. As a result, cpu1 may call >>>> mutex_lock() and wait for it while cpu2 can set the deletion flag later >>>> and get the mutex first before cpu1. So checking for the deletion flag >>>> before taking the mutex isn't enough. >>> Yeah, I figured that out already (crossed emails). BTW, how did you >>> trigger this warning. I'm playing around with adding loop devices, >>> volume groups, and logical volumes, and reading the trace files >>> created in the sysfs directory, then removing those items, but it's >>> not triggering the "delete" path. What operation deletes the partition? >> I'm guessing that deleting an actual partition may work (unfortunately, >> my test box has no partition to delete ;-) I'll find another box to >> test on. >> > OK, deleting a partition doesn't trigger the lockdep splat. But I also > added a printk in the BLKPG_DEL_PARTITION case switch, which also > doesn't print. What command do I need to do to trigger that path? > > Thanks, > > -- Steve
Attached is a reproducer that was used to trigger the warning. Some tuning may be needed depend on the actual configuration of the test machine. Cheers, Longman
run_test.sh
Description: application/shellscript
