Date: Sun, 26 Dec 2010 13:05:43 +0000 (UTC) From: Colin Percival <cperciva@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/i386/xen pmap.c Message-ID: <201012261306.oBQD63tZ003090@repoman.freebsd.org>
next in thread | raw e-mail | index | archive | help
cperciva 2010-12-26 13:05:43 UTC
FreeBSD src repository
Modified files:
sys/i386/xen pmap.c
Log:
SVN rev 216703 on 2010-12-26 13:05:43Z by cperciva
Lock the vm page queue mutex in pmap_pte_release around the call
to PMAP_SET_VA; this fixes a mutex-not-held panic when a process
which called mlock(2) exits, and parallels a change made in
pmap_pte 10 months ago (svn r204160).
Note: The locking in this code is utterly broken. We should not
be using the VM page queue mutex to protect the queue of pending
Xen page mapping hypervisor calls. Even if it made sense to do
so, this commit and r204160 introduce LORs between the vm page
queue mutex and PMAP2mutex.
(However, a possible deadlock is better than a guaranteed panic,
and this change will hopefully make life easier for whoever fixes
the Xen pmap locking in the future.)
PR: kern/140313
MFC after: 3 days
Revision Changes Path
1.55 +2 -0 src/sys/i386/xen/pmap.c
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201012261306.oBQD63tZ003090>