2010-01-23 12:48:20

by Dan Carpenter

Subject: [patch] drbd: null dereference bug

epoch is always NULL here.

Signed-off-by: Dan Carpenter <[email protected]>
---
This patch has only been compile tested. Sorry. :/

--- orig/drivers/block/drbd/drbd_receiver.c 2010-01-23 10:53:13.000000000 +0300
+++ devel/drivers/block/drbd/drbd_receiver.c 2010-01-23 10:54:19.000000000 +0300
@@ -1224,7 +1224,7 @@ static int receive_Barrier(struct drbd_c
epoch = kmalloc(sizeof(struct drbd_epoch), GFP_NOIO);
if (!epoch) {
dev_warn(DEV, "Allocation of an epoch failed, slowing down\n");
- issue_flush = !test_and_set_bit(DE_BARRIER_IN_NEXT_EPOCH_ISSUED, &epoch->flags);
+ issue_flush = !test_and_set_bit(DE_BARRIER_IN_NEXT_EPOCH_ISSUED, &mdev->current_epoch->flags);
drbd_wait_ee_list_empty(mdev, &mdev->active_ee);
if (issue_flush) {
rv = drbd_flush_after_epoch(mdev, mdev->current_epoch);

2010-01-25 17:14:41

by Philipp Reisner

Subject: Re: [Drbd-dev] [patch] drbd: null dereference bug

Am Samstag, 23. Januar 2010 13:45:22 schrieb Dan Carpenter:
> epoch is always NULL here.
>
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> This patch has only been compile tested. Sorry. :/
>
> --- orig/drivers/block/drbd/drbd_receiver.c 2010-01-23 10:53:13.000000000
> +0300 +++ devel/drivers/block/drbd/drbd_receiver.c 2010-01-23
> 10:54:19.000000000 +0300 @@ -1224,7 +1224,7 @@ static int
> receive_Barrier(struct drbd_c
> epoch = kmalloc(sizeof(struct drbd_epoch), GFP_NOIO);
> if (!epoch) {
> dev_warn(DEV, "Allocation of an epoch failed, slowing down\n");
> - issue_flush = !test_and_set_bit(DE_BARRIER_IN_NEXT_EPOCH_ISSUED, &epoch->flags);
> + issue_flush = !test_and_set_bit(DE_BARRIER_IN_NEXT_EPOCH_ISSUED, &mdev->current_epoch->flags);
> drbd_wait_ee_list_empty(mdev, &mdev->active_ee);
> if (issue_flush) {
> rv = drbd_flush_after_epoch(mdev, mdev->current_epoch);
>

The patch is correct. It is going upstream though the DRBD tree.
See:
http://git.drbd.org/?p=linux-2.6-drbd.git;a=commit;h=d3db7b485ad7c467a61279d6a8ef51a3c83352df

-Phil
--
: Dipl-Ing Philipp Reisner
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