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| author | Al Viro <viro@zeniv.linux.org.uk> | 2016-02-27 19:23:16 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-02-27 19:23:16 -0500 |
| commit | d4565649b6d6923369112758212b851adc407f0c (patch) | |
| tree | fc877b8805e9393c4288bdf396cf223de2b144ad /fs/namei.c | |
| parent | c80567c82ae4814a41287618e315a60ecf513be6 (diff) | |
| download | lwn-d4565649b6d6923369112758212b851adc407f0c.tar.gz lwn-d4565649b6d6923369112758212b851adc407f0c.zip | |
namei: ->d_inode of a pinned dentry is stable only for positives
both do_last() and walk_component() risk picking a NULL inode out
of dentry about to become positive, *then* checking its flags and
seeing that it's not negative anymore and using (already stale by
then) value they'd fetched earlier. Usually ends up oopsing soon
after that...
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c index e30deefad8f8..e0881c0bd228 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1743,11 +1743,11 @@ static int walk_component(struct nameidata *nd, int flags) if (err < 0) return err; - inode = d_backing_inode(path.dentry); seq = 0; /* we are already out of RCU mode */ err = -ENOENT; if (d_is_negative(path.dentry)) goto out_path_put; + inode = d_backing_inode(path.dentry); } if (flags & WALK_PUT) @@ -3192,12 +3192,12 @@ retry_lookup: return error; BUG_ON(nd->flags & LOOKUP_RCU); - inode = d_backing_inode(path.dentry); seq = 0; /* out of RCU mode, so the value doesn't matter */ if (unlikely(d_is_negative(path.dentry))) { path_to_nameidata(&path, nd); return -ENOENT; } + inode = d_backing_inode(path.dentry); finish_lookup: if (nd->depth) put_link(nd); |