diff options
| author | Stanislav Kinsbursky <skinsbursky@parallels.com> | 2012-11-26 16:29:42 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-11-26 17:41:24 -0800 |
| commit | 05f564849d49499ced97913a0914b5950577d07d (patch) | |
| tree | eaab16738a3d405084466d5a9aca01db37e41f73 | |
| parent | 56c176c9cac9a77249fa1736bfd792f379d61942 (diff) | |
| download | linux-05f564849d49499ced97913a0914b5950577d07d.tar.bz2 | |
proc: check vma->vm_file before dereferencing
Commit 7b540d0646ce ("proc_map_files_readdir(): don't bother with
grabbing files") switched proc_map_files_readdir() to use @f_mode
directly instead of grabbing @file reference, but same time the test for
@vm_file presence was lost leading to nil dereference. The patch brings
the test back.
The all proc_map_files feature is CONFIG_CHECKPOINT_RESTORE wrapped
(which is set to 'n' by default) so the bug doesn't affect regular
kernels.
The regression is 3.7-rc1 only as far as I can tell.
[gorcunov@openvz.org: provided changelog]
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/proc/base.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 3c231adf8450..9e28356a959a 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1877,8 +1877,9 @@ static struct dentry *proc_map_files_lookup(struct inode *dir, if (!vma) goto out_no_vma; - result = proc_map_files_instantiate(dir, dentry, task, - (void *)(unsigned long)vma->vm_file->f_mode); + if (vma->vm_file) + result = proc_map_files_instantiate(dir, dentry, task, + (void *)(unsigned long)vma->vm_file->f_mode); out_no_vma: up_read(&mm->mmap_sem); |