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authorAndrew Morton <akpm@linux-foundation.org>2013-03-13 14:59:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-13 15:21:47 -0700
commit6d7825b10dbeafd60627cd04291fb10ec2b5b973 (patch)
tree665fe65bbb0f931dc5d89596c0c12d2569638ea3
parentc8615d3716fe327c2540cf514a34b227dc9b39e8 (diff)
mm/fremap.c: fix oops on error path
If find_vma() fails, sys_remap_file_pages() will dereference `vma', which contains NULL. Fix it by checking the pointer. (We could alternatively check for err==0, but this seems more direct) (The vm_flags change is to squish a bogus used-uninitialised warning without adding extra code). Reported-by: Tommi Rantala <tt.rantala@gmail.com> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/fremap.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/fremap.c b/mm/fremap.c
index 0cd4c11488e..6a8da7ee85f 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -163,7 +163,8 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
* and that the remapped range is valid and fully within
* the single existing vma.
*/
- if (!vma || !(vma->vm_flags & VM_SHARED))
+ vm_flags = vma->vm_flags;
+ if (!vma || !(vm_flags & VM_SHARED))
goto out;
if (!vma->vm_ops || !vma->vm_ops->remap_pages)
@@ -254,7 +255,8 @@ get_write_lock:
*/
out:
- vm_flags = vma->vm_flags;
+ if (vma)
+ vm_flags = vma->vm_flags;
if (likely(!has_write_lock))
up_read(&mm->mmap_sem);
else