svn commit: r195783 - stable/7/sys/ufs/ufs

Sean Nicholas Barkas snb at
Mon Jul 20 16:19:43 UTC 2009

Author: snb
Date: Mon Jul 20 16:19:42 2009
New Revision: 195783

  MFC r195003:
  Fix a bug reported by pho@ where one can induce a panic by decreasing
  vfs.ufs.dirhash_maxmem below the current amount of memory used by dirhash. When
  ufsdirhash_build() is called with the memory in use greater than dirhash_maxmem,
  it attempts to free up memory by calling ufsdirhash_recycle(). If successful in
  freeing enough memory, ufsdirhash_recycle() leaves the dirhash list locked. But
  at this point in ufsdirhash_build(), the list is not explicitly unlocked after
  the call(s) to ufsdirhash_recycle(). When we next attempt to lock the dirhash
  list, we will get a "panic: _mtx_lock_sleep: recursed on non-recursive mutex
  dirhash list".
  Approved by:	dwmalone (mentor)


Modified: stable/7/sys/ufs/ufs/ufs_dirhash.c
--- stable/7/sys/ufs/ufs/ufs_dirhash.c	Mon Jul 20 13:55:33 2009	(r195782)
+++ stable/7/sys/ufs/ufs/ufs_dirhash.c	Mon Jul 20 16:19:42 2009	(r195783)
@@ -329,9 +329,12 @@ ufsdirhash_build(struct inode *ip)
 	int dirblocks, i, j, memreqd, nblocks, narrays, nslots, slot;
 	/* Take care of a decreased sysctl value. */
-	while (ufs_dirhashmem > ufs_dirhashmaxmem)
+	while (ufs_dirhashmem > ufs_dirhashmaxmem) {
 		if (ufsdirhash_recycle(0) != 0)
 			return (-1);
+		/* Recycled enough memory, so unlock the list. */
+	}
 	/* Check if we can/should use dirhash. */
 	if (ip->i_size < ufs_mindirhashsize || OFSFMT(ip->i_vnode) ||

More information about the svn-src-stable-7 mailing list