Bug 251511 - mrsas driver causes machine to lock up
Summary: mrsas driver causes machine to lock up
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: CURRENT
Hardware: Any Any
: --- Affects Only Me
Assignee: freebsd-bugs (Nobody)
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-12-01 20:25 UTC by Juraj Lutter
Modified: 2020-12-10 14:38 UTC (History)
0 users

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Description Juraj Lutter freebsd_committer 2020-12-01 20:25:50 UTC
Dell r730xd with PERC H730 hangs under some load (depending on the workload pattern).

Machine runs recent -CURRENT, zroot is mirror pool.

When doing buildworld with -j16, the lockup occurs and the only way out is to reboot, but also ddb can be entered.

Using ddb and "alltrace" I've been able to trace that most of the processes are in sched_switch() and mrsas_ocr0 kernel process sleeps in mrsas_ocr_thread() (mrsas_ocr_thread+0x3d0).

Using "examine/i" from within ddb i've been able to trace that mrsas_ocr_thread+0x3d0 points somewhere into the function (mrsas_ocr_thread()) to a place inside for(;;) loop.

*SOMETIMES* after certain amount of time, the machine runs for minute or two, then the lockup occurs again.

What else can I try? Here my kernel-fu ends :-(

I'm not sure whether this is caused by scheduler problem(s), interrupt(s) problem(s) or mrsas driver as such.

Any help is appreciated. I repeat again that if there is a need for a debug session, we can arrange one.
Comment 1 Andriy Gapon freebsd_committer 2020-12-02 07:54:47 UTC
You can get a crash dump from ddb prompt.
Then the problem would be easier to analyze.
Comment 2 Juraj Lutter freebsd_committer 2020-12-10 14:38:24 UTC
Were there any significant changes recently? The problem seems to be gone now.

I can see that there were some changes to threading and/or scheduler.