gfs2: Fix potential glock use-after-free on unmount

Browse source

When a DLM lockspace is released and there ares still locks in that
lockspace, DLM will unlock those locks automatically.  Commit
fb6791d100 started exploiting this behavior to speed up filesystem
unmount: gfs2 would simply free glocks it didn't want to unlock and then
release the lockspace.  This didn't take the bast callbacks for
asynchronous lock contention notifications into account, which remain
active until until a lock is unlocked or its lockspace is released.

To prevent those callbacks from accessing deallocated objects, put the
glocks that should not be unlocked on the sd_dead_glocks list, release
the lockspace, and only then free those glocks.

As an additional measure, ignore unexpected ast and bast callbacks if
the receiving glock is dead.

Fixes: fb6791d100 ("GFS2: skip dlm_unlock calls in unmount")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: David Teigland <teigland@redhat.com>

...

This commit is contained in:

Andreas Gruenbacher 2024-04-10 04:50:18 +02:00

parent 59f6000579

commit d98779e687

6 changed files with 57 additions and 16 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

35

fs/gfs2/glock.c

View file

1

fs/gfs2/glock.h

View file

1

fs/gfs2/incore.h

View file

32

fs/gfs2/lock_dlm.c

View file

1

fs/gfs2/ops_fstype.c

View file

3

fs/gfs2/super.c

View file