[Bug 256937] Kernel panic on FUSE filesystem - lockmgr_xlock_hard: recursing on non recursive lockmgr

From: <bugzilla-noreply_at_freebsd.org>
Date: Fri, 02 Jul 2021 12:01:47 +0000
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256937

            Bug ID: 256937
           Summary: Kernel panic on FUSE filesystem - lockmgr_xlock_hard:
                    recursing on non recursive lockmgr
           Product: Base System
           Version: 13.0-RELEASE
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Some People
          Priority: ---
         Component: kern
          Assignee: bugs_at_FreeBSD.org
          Reporter: chogata_at_moosefs.pro

Created attachment 226169
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=226169&action=edit
Kernel panic backtrace message

The problem is repeatedly spotted on a machine with FreeBSD 13.0 running
MooseFS client that uses FUSE. The machine crashes daily, I'm attaching a
screenshot of panic backtrace. It was reported to MooseFS team by a user and we
promised to help investigate the problem.

>From the fact, that this FreeBSD machine logs repeatedly:
"fuse_internal_do_getattr: cache incoherent on [PATH]! Buggy FUSE server
detected" and the backtrace that shows an attempt at write and then invokes
"fuse_internal_do_getattr", we suspect that the kernel panics when it gets a
different length than it has in its internal structures and tries to invalidate
the data cache buffer, which triggers a second attempt to lock an already
locked buffer lock and that this might be somehow related to the kernel
behaviour described in bug #256936

I will be pointing out this thread to the user that experiences the crashes, he
will be able to add any details about the exact configuration of the affected
system.

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Received on Fri Jul 02 2021 - 12:01:47 UTC

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