Messages in this thread | | | Subject | Re: RCU stall | From | Bart Van Assche <> | Date | Tue, 22 Mar 2016 16:53:26 -0700 |
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On 03/22/2016 01:45 PM, Paul E. McKenney wrote: > You are getting a soft lockup as well as an RCU CPU stall warning, so > it looks like something is taking a very long time in blk_done_softirq(). > > You have multiple occurrences at different times, so it looks to be > a long time as opposed to an infinite time. Are you perhaps doing > something that would make a huge amount of work for blk_done_softirq()? > > See Documentation/RCU/stallwarn.txt in the kernel source tree for more > info on how to debug this sort of thing.
Hello Paul,
None of the drivers involved in the test I ran contain RCU code that has been changed recently. The block and SCSI subsystems processes I/O completions in softirq context but until last week I hadn't seen any RCU lockup complaints when I ran an SRP test against a kernel with lockdep and several other kernel debugging options enabled. This is why I sent an e-mail to you. I have read Documentation/RCU/stallwarn.txt after I received your reply but this didn't provide me any clue about where to look for the root cause. Any further help would be appreciated.
Thanks,
Bart.
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