fix fs->lock deadlock

David Mosberger (davidm@napali.hpl.hp.com)
Wed, 16 Apr 2003 10:43:52 -0700


The patch below is needed to avoid a deadlock on fs->lock. Without
the patch, if __emul_lookup_dentry() returns 0, we fail to reacquire
current->fs->lock and then go ahead to read_unlock() it anyhow. Bad
for your health.

I believe the bug was introduced by this change set (about 9 weeks ago):

http://linux.bkbits.net:8080/linux-2.5/diffs/fs/namei.c@1.63.1.2

--david

===== fs/namei.c 1.69 vs edited =====
--- 1.69/fs/namei.c Wed Apr 2 22:51:31 2003
+++ edited/fs/namei.c Wed Apr 16 10:18:40 2003
@@ -847,6 +847,7 @@
read_unlock(&current->fs->lock);
if (__emul_lookup_dentry(name,nd))
return 0;
+ read_lock(&current->fs->lock);
}
nd->mnt = mntget(current->fs->rootmnt);
nd->dentry = dget(current->fs->root);
-
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