On 15/11/24 21:40, Jens Axboe wrote:
On 11/15/24 9:07 AM, Suraj Sonawane wrote:
On 08/10/24 23:22, SurajSonawane2415 wrote:
Fix the uninitialized symbol 'bio' in the function blk_rq_prep_clone
to resolve the following error:
block/blk-mq.c:3199 blk_rq_prep_clone() error: uninitialized symbol 'bio'.
Signed-off-by: SurajSonawane2415 <surajsonawane0215@xxxxxxxxx>
---
V1 - Initialize 'bio' to NULL.
V2 - Move bio_put(bio) into the bio_ctr error handling block,
ensuring memory cleanup occurs only when the bio_ctr fail.
V3 - Moved the bio declaration into the loop scope, eliminating
the need to set it to NULL at the end of the loop.
V4 - Adjusted position of arguments of bio_alloc_clone.
block/blk-mq.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4b2c8e940..89c9a6c4d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3156,19 +3156,21 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
int (*bio_ctr)(struct bio *, struct bio *, void *),
void *data)
{
- struct bio *bio, *bio_src;
+ struct bio *bio_src;
if (!bs)
bs = &fs_bio_set;
__rq_for_each_bio(bio_src, rq_src) {
- bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask,
- bs);
+ struct bio *bio = bio_alloc_clone(rq->q->disk->part0, bio_src,
+ gfp_mask, bs);
if (!bio)
goto free_and_out;
- if (bio_ctr && bio_ctr(bio, bio_src, data))
+ if (bio_ctr && bio_ctr(bio, bio_src, data)) {
+ bio_put(bio);
goto free_and_out;
+ }
if (rq->bio) {
rq->biotail->bi_next = bio;
@@ -3176,7 +3178,6 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
} else {
rq->bio = rq->biotail = bio;
}
- bio = NULL;
}
/* Copy attributes of the original request to the clone request. */
@@ -3196,8 +3197,6 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
return 0;
free_and_out:
- if (bio)
- bio_put(bio);
blk_rq_unprep_clone(rq);
return -ENOMEM;
Hello Jens!
I wanted to follow up on this patch I submitted. I have done all the
suggested changes till v4. I was wondering if you had a chance to
review it and if there are any comments or feedback.
Sorry missed this one. Is this a legit case of it being used
uninitialized, or is it just cleaning up the code so that smatch is
happy? The commit is woefully non-descriptive, unfortunately. So perhaps
resend this one and improve the commit message.
Apologies for any confusion earlier, and thank you for your attention to
this. After further analysis, I realize that this change isn't
necessary, as bio is already set to NULL by bio_alloc_clone on failure,
preventing any real case of uninitialized use. My initial patch aimed to
clean up the code and satisfy smatch, ensuring better readability and
error handling.
I appreciate your feedback and the opportunity to learn from this. I now
understand that no change is needed here. Thank you for your guidance
and understanding.
Best regards,
Suraj Sonawane
