projects/linux·commit 5c0c1654

mempolicy: fix dangling reference to tmpfs superblock mpol

5c0c1654 · Lee Schermerhorn <[email protected]> · 2010-06-29 15:05:30 -07:00

My patch to "Factor out duplicate put/frees in mpol_shared_policy_init()
to a common return path"; and Dan Carpenter's fix thereto both left a
dangling reference to the incoming tmpfs superblock mempolicy structure.
A similar leak was introduced earlier when the nodemask was moved offstack
to the scratch area despite the note in the comment block regarding the
incoming ref.

Move the remaining 'put of the incoming "mpol" to the common exit path to
drop the reference.

Signed-off-by: Lee Schermerhorn <[email protected]>
Acked-by: Dan Carpenter <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Christoph Lameter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Commit
5c0c165490e763eddcbb0b6c8c41ab5cc11ddea0
Parents
56480287

Changes

1 files changed · +5 −4

FileStatusAddDelContent
mm/mempolicy.cmodified+5−4View file

mm/mempolicy.c

View file
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 5d6fb33..5bc0a96 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2094,7 +2094,7 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
NODEMASK_SCRATCH(scratch);
if (!scratch)
- return;
+ goto put_mpol;
/* contextualize the tmpfs mount point mempolicy */
new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
if (IS_ERR(new))
@@ -2103,19 +2103,20 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
task_lock(current);
ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
task_unlock(current);
- mpol_put(mpol); /* drop our ref on sb mpol */
if (ret)
- goto put_free;
+ goto put_new;
/* Create pseudo-vma that contains just the policy */
memset(&pvma, 0, sizeof(struct vm_area_struct));
pvma.vm_end = TASK_SIZE; /* policy covers entire file */
mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
-put_free:
+put_new:
mpol_put(new); /* drop initial ref */
free_scratch:
NODEMASK_SCRATCH_FREE(scratch);
+put_mpol:
+ mpol_put(mpol); /* drop our incoming ref on sb mpol */
}
}