diff options
| author | Török Edwin <edwintorok@gmail.com> | 2011-06-15 23:06:14 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-06-16 17:27:39 +0200 |
| commit | 50338b889dc504c69e0cb316ac92d1b9e51f3c8a (patch) | |
| tree | 8e353de07b21b350664eff5d69f3a67014d01bcd /fs/namei.c | |
| parent | Delay struct net freeing while there's a sysfs instance refering to it (diff) | |
| download | linux-50338b889dc504c69e0cb316ac92d1b9e51f3c8a.tar.xz linux-50338b889dc504c69e0cb316ac92d1b9e51f3c8a.zip | |
fix wrong iput on d_inode introduced by e6bc45d65d
Git bisection shows that commit e6bc45d65df8599fdbae73be9cec4ceed274db53 causes
BUG_ONs under high I/O load:
kernel BUG at fs/inode.c:1368!
[ 2862.501007] Call Trace:
[ 2862.501007] [<ffffffff811691d8>] d_kill+0xf8/0x140
[ 2862.501007] [<ffffffff81169c19>] dput+0xc9/0x190
[ 2862.501007] [<ffffffff8115577f>] fput+0x15f/0x210
[ 2862.501007] [<ffffffff81152171>] filp_close+0x61/0x90
[ 2862.501007] [<ffffffff81152251>] sys_close+0xb1/0x110
[ 2862.501007] [<ffffffff814c14fb>] system_call_fastpath+0x16/0x1b
A reliable way to reproduce this bug is:
Login to KDE, run 'rsnapshot sync', and apt-get install openjdk-6-jdk,
and apt-get remove openjdk-6-jdk.
The buggy part of the patch is this:
struct inode *inode = NULL;
.....
- if (nd.last.name[nd.last.len])
- goto slashes;
inode = dentry->d_inode;
- if (inode)
- ihold(inode);
+ if (nd.last.name[nd.last.len] || !inode)
+ goto slashes;
+ ihold(inode)
...
if (inode)
iput(inode); /* truncate the inode here */
If nd.last.name[nd.last.len] is nonzero (and thus goto slashes branch is taken),
and dentry->d_inode is non-NULL, then this code now does an additional iput on
the inode, which is wrong.
Fix this by only setting the inode variable if nd.last.name[nd.last.len] is 0.
Reference: https://lkml.org/lkml/2011/6/15/50
Reported-by: Norbert Preining <preining@logic.at>
Reported-by: Török Edwin <edwintorok@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Török Edwin <edwintorok@gmail.com>
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, 3 insertions, 1 deletions
diff --git a/fs/namei.c b/fs/namei.c index 9802345df5e7..6301963b161f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2713,8 +2713,10 @@ static long do_unlinkat(int dfd, const char __user *pathname) error = PTR_ERR(dentry); if (!IS_ERR(dentry)) { /* Why not before? Because we want correct error value */ + if (nd.last.name[nd.last.len]) + goto slashes; inode = dentry->d_inode; - if (nd.last.name[nd.last.len] || !inode) + if (!inode) goto slashes; ihold(inode); error = mnt_want_write(nd.path.mnt); |