Date: Fri, 27 Jul 2001 00:39:29 +0200 From: Thomas Moestl <tmm@FreeBSD.org> To: freebsd-stable@FreeBSD.org, freebsd-smp@FreeBSD.org Cc: Ian Dowse <iedowse@FreeBSD.org> Subject: Please test: -stable SMP locking fix Message-ID: <20010727003929.B73365@crow.dom2ip.de>
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[-- Attachment #1 --]
Hi,
I have attached a patch that should fix some panics (caused by
sleeping with a lock held) and lock-order reversals on -stable SMP
systems. These usually only seem to occur when using NFS.
I'd like to commit this fix before 4.4 is released (if I can make
it). Due to locking changes, this will need to be solved differently
on -current, so it will need to be directly committed to -stable.
Therefore, to anybody who uses stable on an SMP box (and dares ;):
please, please test this, and report back any problems! If you do,
please drop me a private mail so that I get an idea about the test
coverage that it got.
The risk should be relatively low (this removes a lock/unlock pair,
but all relevant code should also be protected by the mp_lock).
On UP machines, this patch does not change anything at all.
- thomas
[-- Attachment #2 --]
Index: vfs_subr.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_subr.c,v
retrieving revision 1.249.2.9
diff -u -r1.249.2.9 vfs_subr.c
--- vfs_subr.c 2001/06/26 04:20:08 1.249.2.9
+++ vfs_subr.c 2001/07/25 21:35:01
@@ -730,12 +730,10 @@
/*
* Destroy the copy in the VM cache, too.
*/
- simple_lock(&vp->v_interlock);
if (VOP_GETVOBJECT(vp, &object) == 0) {
vm_object_page_remove(object, 0, 0,
(flags & V_SAVE) ? TRUE : FALSE);
}
- simple_unlock(&vp->v_interlock);
if (!TAILQ_EMPTY(&vp->v_dirtyblkhd) || !TAILQ_EMPTY(&vp->v_cleanblkhd))
panic("vinvalbuf: flush failed");
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