The patch titled
From: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
has been added to the -mm tree. Its filename is
proc-check-vma-vm_file-before-dereferencing.patch
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------------------------------------------------------
From: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
Subject: proc: check vma->vm_file before dereferencing
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@xxxxxxxxxx: provided changelog]
Signed-off-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
Acked-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/base.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff -puN fs/proc/base.c~proc-check-vma-vm_file-before-dereferencing fs/proc/base.c
--- a/fs/proc/base.c~proc-check-vma-vm_file-before-dereferencing
+++ a/fs/proc/base.c
@@ -1770,8 +1770,9 @@ static struct dentry *proc_map_files_loo
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);
_
Patches currently in -mm which might be from skinsbursky@xxxxxxxxxxxxx are
proc-check-vma-vm_file-before-dereferencing.patch
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