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| author | rmacklem <rmacklem@FreeBSD.org> | 2011-04-23 11:22:48 +0000 |
|---|---|---|
| committer | rmacklem <rmacklem@FreeBSD.org> | 2011-04-23 11:22:48 +0000 |
| commit | 872195caf937fd6dc952eeeed83c61258243bb32 (patch) | |
| tree | 39ec7be656a9fd85e5de051f09d259121956453c /sys/kern | |
| parent | a7ea422c215b35f93dc97bc50124c508d23a045b (diff) | |
| download | FreeBSD-src-872195caf937fd6dc952eeeed83c61258243bb32.zip FreeBSD-src-872195caf937fd6dc952eeeed83c61258243bb32.tar.gz | |
Fix a LOR in vfs_busy() where, after msleeping, it would lock
the mutexes in the wrong order for the case where the
MBF_MNTLSTLOCK is set. I believe this did have the
potential for deadlock. For example, if multiple nfsd threads
called vfs_busyfs(), which calls vfs_busy() with MBF_MNTLSTLOCK.
Thanks go to pho for catching this during his testing.
Tested by: pho
Submitted by: kib
MFC after: 2 weeks
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/vfs_subr.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c index 5809dbb..25bfa7c 100644 --- a/sys/kern/vfs_subr.c +++ b/sys/kern/vfs_subr.c @@ -377,9 +377,10 @@ vfs_busy(struct mount *mp, int flags) if (flags & MBF_MNTLSTLOCK) mtx_unlock(&mountlist_mtx); mp->mnt_kern_flag |= MNTK_MWAIT; - msleep(mp, MNT_MTX(mp), PVFS, "vfs_busy", 0); + msleep(mp, MNT_MTX(mp), PVFS | PDROP, "vfs_busy", 0); if (flags & MBF_MNTLSTLOCK) mtx_lock(&mountlist_mtx); + MNT_ILOCK(mp); } if (flags & MBF_MNTLSTLOCK) mtx_unlock(&mountlist_mtx); |
