On 3/25/22 11:27 AM, xkernel.wang@xxxxxxxxxxx wrote:
From: Xiaoke Wang <xkernel.wang@xxxxxxxxxxx>
kzalloc() is a memory allocation function which can return NULL when
some internal memory errors happen. So it is better to check it to
prevent potential wrong memory access.
Signed-off-by: Xiaoke Wang <xkernel.wang@xxxxxxxxxxx>
---
Note: I just roughly handled the error and this seems to affect the
original functionality. If this cannot fail, maybe the tag
`__GFP_NOFAIL` should be considered.
The error handling is incorrect indeed. And IIRC there is someone else
already fixes it properly and the patch is not upstream yet.
Thanks.
Coly Li
drivers/md/bcache/request.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 6d1de88..1dc9821 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -1107,14 +1107,16 @@ static void detached_dev_do_request(struct bcache_device *d, struct bio *bio,
* which would call closure_get(&dc->disk.cl)
*/
ddip = kzalloc(sizeof(struct detached_dev_io_private), GFP_NOIO);
- ddip->d = d;
- /* Count on the bcache device */
- ddip->orig_bdev = orig_bdev;
- ddip->start_time = start_time;
- ddip->bi_end_io = bio->bi_end_io;
- ddip->bi_private = bio->bi_private;
- bio->bi_end_io = detached_dev_end_io;
- bio->bi_private = ddip;
+ if (ddip) {
+ ddip->d = d;
+ /* Count on the bcache device */
+ ddip->orig_bdev = orig_bdev;
+ ddip->start_time = start_time;
+ ddip->bi_end_io = bio->bi_end_io;
+ ddip->bi_private = bio->bi_private;
+ bio->bi_end_io = detached_dev_end_io;
+ bio->bi_private = ddip;
+ }
if ((bio_op(bio) == REQ_OP_DISCARD) &&
!blk_queue_discard(bdev_get_queue(dc->bdev)))
