[android-common:android16-6.12 1/1] block/blk-merge.c:969 blk_rq_merge_ok() warn: variable dereferenced before check 'rq->bio' (see line 958)

BCC: [email protected]
CC: [email protected]
TO: [email protected]

tree:   https://android.googlesource.com/kernel/common android16-6.12
head:   d36feda1de5741a9d2bfe0fd6a0391c77047f5bb
commit: 7f82cf03ba776076d22aebf90449ec2b83618cef [1/1] UPSTREAM: block: remove the write_hint field from struct request
:::::: branch date: 12 hours ago
:::::: commit date: 11 months ago
config: x86_64-randconfig-161 (https://download.01.org/0day-ci/archive/20260703/[email protected]/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
smatch: v0.5.0-9185-gbcc58b9c

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Reported-by: Dan Carpenter <[email protected]>
| Closes: https://lore.kernel.org/r/[email protected]/

smatch warnings:
block/blk-merge.c:969 blk_rq_merge_ok() warn: variable dereferenced before check 'rq->bio' (see line 958)

vim +969 block/blk-merge.c

050c8ea80e3e900 Tejun Heo          2012-02-08  944  
050c8ea80e3e900 Tejun Heo          2012-02-08  945  bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
050c8ea80e3e900 Tejun Heo          2012-02-08  946  {
e2a60da74fc8215 Martin K. Petersen 2012-09-18  947  	if (!rq_mergeable(rq) || !bio_mergeable(bio))
050c8ea80e3e900 Tejun Heo          2012-02-08  948  		return false;
050c8ea80e3e900 Tejun Heo          2012-02-08  949  
288dab8a35a0bde Christoph Hellwig  2016-06-09  950  	if (req_op(rq) != bio_op(bio))
f31dc1cd490539e Martin K. Petersen 2012-09-18  951  		return false;
f31dc1cd490539e Martin K. Petersen 2012-09-18  952  
050c8ea80e3e900 Tejun Heo          2012-02-08  953  	/* different data direction or already started, don't merge */
050c8ea80e3e900 Tejun Heo          2012-02-08  954  	if (bio_data_dir(bio) != rq_data_dir(rq))
050c8ea80e3e900 Tejun Heo          2012-02-08  955  		return false;
050c8ea80e3e900 Tejun Heo          2012-02-08  956  
6b2b04590b51aa4 Tejun Heo          2022-03-14  957  	/* don't merge across cgroup boundaries */
6b2b04590b51aa4 Tejun Heo          2022-03-14 @958  	if (!blk_cgroup_mergeable(rq, bio))
6b2b04590b51aa4 Tejun Heo          2022-03-14  959  		return false;
6b2b04590b51aa4 Tejun Heo          2022-03-14  960  
050c8ea80e3e900 Tejun Heo          2012-02-08  961  	/* only merge integrity protected bio into ditto rq */
4eaf99beadcefbf Martin K. Petersen 2014-09-26  962  	if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
050c8ea80e3e900 Tejun Heo          2012-02-08  963  		return false;
050c8ea80e3e900 Tejun Heo          2012-02-08  964  
a892c8d52c02284 Satya Tangirala    2020-05-14  965  	/* Only merge if the crypt contexts are compatible */
a892c8d52c02284 Satya Tangirala    2020-05-14  966  	if (!bio_crypt_rq_ctx_compatible(rq, bio))
a892c8d52c02284 Satya Tangirala    2020-05-14  967  		return false;
a892c8d52c02284 Satya Tangirala    2020-05-14  968  
7f82cf03ba77607 Christoph Hellwig  2024-11-12 @969  	if (rq->bio) {
449813515d3e5ef Bart Van Assche    2024-02-02  970  		/* Don't merge requests with different write hints. */
7f82cf03ba77607 Christoph Hellwig  2024-11-12  971  		if (rq->bio->bi_write_hint != bio->bi_write_hint)
449813515d3e5ef Bart Van Assche    2024-02-02  972  			return false;
7f82cf03ba77607 Christoph Hellwig  2024-11-12  973  	}
668ffc03418bc77 Damien Le Moal     2018-11-20  974  
69db0304309a7e4 Greg Kroah-Hartman 2025-05-21  975  	if (rq->ioprio != bio_prio(bio))
69db0304309a7e4 Greg Kroah-Hartman 2025-05-21  976  		return false;
69db0304309a7e4 Greg Kroah-Hartman 2025-05-21  977  
9da3d1e912f3953 John Garry         2024-06-20  978  	if (blk_atomic_write_mergeable_rq_bio(rq, bio) == false)
9da3d1e912f3953 John Garry         2024-06-20  979  		return false;
9da3d1e912f3953 John Garry         2024-06-20  980  
050c8ea80e3e900 Tejun Heo          2012-02-08  981  	return true;
050c8ea80e3e900 Tejun Heo          2012-02-08  982  }
050c8ea80e3e900 Tejun Heo          2012-02-08  983  

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