diff options
| author | Darrick J. Wong <djwong@us.ibm.com> | 2007-05-08 00:25:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 11:15:02 -0700 |
| commit | 59cd0cbc75367b82f704f63b104117462275060d (patch) | |
| tree | 695c4f7af4cf840a7e22e7767e1b5705e0b6d8d1 /fs/proc/generic.c | |
| parent | 7695650a924a6859910c8c19dfa43b4d08224d66 (diff) | |
Fix race between proc_readdir and remove_proc_entry
Fix the following race:
proc_readdir remove_proc_entry
============ =================
spin_lock(&proc_subdir_lock);
[choose PDE to start filldir from]
spin_unlock(&proc_subdir_lock);
spin_lock(&proc_subdir_lock);
[find PDE]
[free PDE, refcount is 0]
spin_unlock(&proc_subdir_lock);
/* boom */
if (filldir(dirent, de->name, ...
[de_put on error path --adobriyan]
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc/generic.c')
| -rw-r--r-- | fs/proc/generic.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 22a08ff3475d..8a40e15f5ecb 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -478,14 +478,21 @@ int proc_readdir(struct file * filp, } do { + struct proc_dir_entry *next; + /* filldir passes info to user space */ + de_get(de); spin_unlock(&proc_subdir_lock); if (filldir(dirent, de->name, de->namelen, filp->f_pos, - de->low_ino, de->mode >> 12) < 0) + de->low_ino, de->mode >> 12) < 0) { + de_put(de); goto out; + } spin_lock(&proc_subdir_lock); filp->f_pos++; - de = de->next; + next = de->next; + de_put(de); + de = next; } while (de); spin_unlock(&proc_subdir_lock); } |