CVS commit: src/sys/dev/dkwedge

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Fri Apr 21 18:30:32 UTC 2023

Modified Files:
        src/sys/dev/dkwedge: dk.c

Log Message:
dk(4): Fix callout detach race.

1. Set a flag sc_iostop under the lock sc_iolock so dkwedge_detach
   and dkstart don't race over it.

2. Decline to schedule the callout if sc_iostop is set.  The callout
   is already only ever scheduled while the lock is held.

3. Use callout_halt to wait for any concurrent callout to complete.
   At this point, it can't reschedule itself.

Without this change, the callout could be concurrently rescheduling
itself as we issue callout_stop, leading to use-after-free later.


To generate a diff of this commit:
cvs rdiff -u -r1.141 -r1.142 src/sys/dev/dkwedge/dk.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.