| Message ID | 1616500116-3411-2-git-send-email-sergei.shtepa@veeam.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: fix potential infinite loop in the negative branch in __submit_bio_noacct_mq() | expand |
On Tue, Mar 23, 2021 at 02:48:36PM +0300, Sergei Shtepa wrote: > When the blk_crypto_bio_prep() function returns false, the processing > of the bio request must end. Repeated access to blk_crypto_bio_prep() > for this same bio may lead to access to already released data, since in > this case the bio_endio() function was already called for bio. > > The changes allow to leave the processing of the failed bio and > go to the next one from the bio_list. > > The error can only occur when using inline encryption on > request-based blk-mq devices and something went wrong in the > __blk_crypto_bio_prep(). A continue in a do { } while statement evaluates the while condition, so your patch is a no-op.
The 03/24/2021 11:18, Christoph Hellwig wrote: > On Tue, Mar 23, 2021 at 02:48:36PM +0300, Sergei Shtepa wrote: > > When the blk_crypto_bio_prep() function returns false, the processing > > of the bio request must end. Repeated access to blk_crypto_bio_prep() > > for this same bio may lead to access to already released data, since in > > this case the bio_endio() function was already called for bio. > > > > The changes allow to leave the processing of the failed bio and > > go to the next one from the bio_list. > > > > The error can only occur when using inline encryption on > > request-based blk-mq devices and something went wrong in the > > __blk_crypto_bio_prep(). > > A continue in a do { } while statement evaluates the while condition, > so your patch is a no-op. Thank you Christoph! Shame on my bald head. I apologize and will be more attentive in the future.
diff --git a/block/blk-core.c b/block/blk-core.c index fc60ff208497..825df223b01d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1005,13 +1005,12 @@ static blk_qc_t __submit_bio_noacct_mq(struct bio *bio) if (unlikely(bio_queue_enter(bio) != 0)) continue; - if (!blk_crypto_bio_prep(&bio)) { + if (blk_crypto_bio_prep(&bio)) + ret = blk_mq_submit_bio(bio); + else { blk_queue_exit(disk->queue); ret = BLK_QC_T_NONE; - continue; } - - ret = blk_mq_submit_bio(bio); } while ((bio = bio_list_pop(&bio_list[0]))); current->bio_list = NULL;
When the blk_crypto_bio_prep() function returns false, the processing of the bio request must end. Repeated access to blk_crypto_bio_prep() for this same bio may lead to access to already released data, since in this case the bio_endio() function was already called for bio. The changes allow to leave the processing of the failed bio and go to the next one from the bio_list. The error can only occur when using inline encryption on request-based blk-mq devices and something went wrong in the __blk_crypto_bio_prep(). Signed-off-by: Sergei Shtepa <sergei.shtepa@veeam.com> --- block/blk-core.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)