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authorPhilipp Reisner <philipp.reisner@linbit.com>2012-10-19 14:19:23 +0200
committerPhilipp Reisner <philipp.reisner@linbit.com>2012-11-09 14:11:42 +0100
commitfd0017c1243b2b9058525672b9ea13272fb51b30 (patch)
tree529e6eaef73f2ac210e12f9bc4eb8a6178e1894c /drivers
parent4035e4c2ebeb6ac1acbf4e5dd8a759fcf93ff8da (diff)
downloadvexpress-lsk-fd0017c1243b2b9058525672b9ea13272fb51b30.tar.gz
drbd: fix regression: potential NULL pointer dereference
recent commit drbd: always write bitmap on detach introduced a bitmap writeout during detach, which obviously needs some meta data device to write to. Unfortunately, that same error path may be taken if we fail to attach, e.g. due to UUID mismatch, after we changed state to D_ATTACHING, but before the lower level device pointer is even assigned. We need to test for presence of mdev->ldev. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/drbd/drbd_int.h5
-rw-r--r--drivers/block/drbd/drbd_main.c8
2 files changed, 11 insertions, 2 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 32a9ab67a5f..057ffed6eb7 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -2318,6 +2318,11 @@ static inline void drbd_md_flush(struct drbd_conf *mdev)
{
int r;
+ if (mdev->ldev == NULL) {
+ dev_warn(DEV, "mdev->ldev == NULL in drbd_md_flush\n");
+ return;
+ }
+
if (test_bit(MD_NO_FUA, &mdev->flags))
return;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 0f73e157dee..be4f5827712 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3235,8 +3235,12 @@ static int w_go_diskless(struct drbd_work *w, int unused)
* (Do we want a specific meta data flag for this?)
*
* If that does not make it to stable storage either,
- * we cannot do anything about that anymore. */
- if (mdev->bitmap) {
+ * we cannot do anything about that anymore.
+ *
+ * We still need to check if both bitmap and ldev are present, we may
+ * end up here after a failed attach, before ldev was even assigned.
+ */
+ if (mdev->bitmap && mdev->ldev) {
if (drbd_bitmap_io_from_worker(mdev, drbd_bm_write,
"detach", BM_LOCKED_MASK)) {
if (test_bit(WAS_READ_ERROR, &mdev->flags)) {