PR/57574 CVS commit: src

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

The following reply was made to PR kern/57574; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/57574 CVS commit: src
Date: Wed, 9 Aug 2023 08:23:14 +0000

 Module Name:	src
 Committed By:	riastradh
 Date:		Wed Aug  9 08:23:13 UTC 2023
 
 Modified Files:
 	src/sys/kern: subr_workqueue.c
 	src/tests/rump/rumpkern: t_workqueue.c
 
 Log Message:
 workqueue(9): Avoid touching running work items in workqueue_wait.
 
 As soon as the workqueue function has called, it is forbidden to
 touch the struct work passed to it -- the function might free or
 reuse the data structure it is embedded in.
 
 So workqueue_wait is forbidden to search the queue for the batch of
 running work items.  Instead, use a generation number which is odd
 while the thread is processing a batch of work and even when not.
 
 There's still a small optimization available with the struct work
 pointer to wait for: if we find the work item in one of the per-CPU
 _pending_ queues, then after we wait for a batch of work to complete
 on that CPU, we don't need to wait for work on any other CPUs.
 
 PR kern/57574
 
 XXX pullup-10
 XXX pullup-9
 XXX pullup-8
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.41 -r1.42 src/sys/kern/subr_workqueue.c
 cvs rdiff -u -r1.3 -r1.4 src/tests/rump/rumpkern/t_workqueue.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.