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author | Amir Goldstein <amir73il@gmail.com> | 2024-04-05 16:56:35 +0200 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2024-04-14 12:55:46 +0200 |
commit | 16b52bbee4823b01ab7fe3919373c981a38f3797 (patch) | |
tree | ce7a54dd66475297874f9a14c370bb8a6aabb9c6 /fs/kernfs/file.c | |
parent | Linux 6.9-rc3 (diff) | |
download | linux-16b52bbee4823b01ab7fe3919373c981a38f3797.tar.xz linux-16b52bbee4823b01ab7fe3919373c981a38f3797.zip |
kernfs: annotate different lockdep class for of->mutex of writable files
The writable file /sys/power/resume may call vfs lookup helpers for
arbitrary paths and readonly files can be read by overlayfs from vfs
helpers when sysfs is a lower layer of overalyfs.
To avoid a lockdep warning of circular dependency between overlayfs
inode lock and kernfs of->mutex, use a different lockdep class for
writable and readonly kernfs files.
Reported-by: syzbot+9a5b0ced8b1bfb238b56@syzkaller.appspotmail.com
Fixes: 0fedefd4c4e3 ("kernfs: sysfs: support custom llseek method for sysfs entries")
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to '')
-rw-r--r-- | fs/kernfs/file.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index e9df2f87072c..8502ef68459b 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -636,11 +636,18 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) * each file a separate locking class. Let's differentiate on * whether the file has mmap or not for now. * - * Both paths of the branch look the same. They're supposed to + * For similar reasons, writable and readonly files are given different + * lockdep key, because the writable file /sys/power/resume may call vfs + * lookup helpers for arbitrary paths and readonly files can be read by + * overlayfs from vfs helpers when sysfs is a lower layer of overalyfs. + * + * All three cases look the same. They're supposed to * look that way and give @of->mutex different static lockdep keys. */ if (has_mmap) mutex_init(&of->mutex); + else if (file->f_mode & FMODE_WRITE) + mutex_init(&of->mutex); else mutex_init(&of->mutex); |