[android-common:android13-5.15 8/8] drivers/nvme/host/multipath.c:332 nvme_ns_head_submit_bio() warn: variable dereferenced before check 'bio' (see line 320)

[kernel test robot <lkp@intel.com>]

Unfiltered warning: this smatch report is sent as-is and has not been
reviewed for false positives, so please treat it with due skepticism.

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: cros-kernel-buildreports@googlegroups.com

tree:   https://android.googlesource.com/kernel/common android13-5.15
head:   0bb006856b8d8b803fde48d026d89a5fafcd5263
commit: 7ec9a45fc4ee7fc1054c2cabf8b09a6bc708472e [8/8] block: handle bio_split_to_limits() NULL return
:::::: branch date: 8 hours ago
:::::: commit date: 3 years, 9 months ago
config: arm-randconfig-r2200-20261019 (https://download.01.org/0day-ci/archive/20261020/202610200148.xdHHqCtw-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 11.5.0
smatch: v0.5.0-9187-g5189e3fb

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 <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202610200148.xdHHqCtw-lkp@intel.com/

New smatch warnings:
drivers/nvme/host/multipath.c:332 nvme_ns_head_submit_bio() warn: variable dereferenced before check 'bio' (see line 320)

Old smatch warnings:
drivers/nvme/host/multipath.c:869 nvme_mpath_init_identify() warn: missing error code 'error'

vim +/bio +332 drivers/nvme/host/multipath.c

0157ec8dad3c8fc Sagi Grimberg     2019-07-25  317  
1496bd4936d215f Christoph Hellwig 2021-04-07  318  static blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
32acab3181c7053 Christoph Hellwig 2017-11-02  319  {
309dca309fc39a9 Christoph Hellwig 2021-01-24 @320  	struct nvme_ns_head *head = bio->bi_bdev->bd_disk->private_data;
32acab3181c7053 Christoph Hellwig 2017-11-02  321  	struct device *dev = disk_to_dev(head->disk);
32acab3181c7053 Christoph Hellwig 2017-11-02  322  	struct nvme_ns *ns;
32acab3181c7053 Christoph Hellwig 2017-11-02  323  	blk_qc_t ret = BLK_QC_T_NONE;
32acab3181c7053 Christoph Hellwig 2017-11-02  324  	int srcu_idx;
32acab3181c7053 Christoph Hellwig 2017-11-02  325  
525aa5a705d86e1 Hannes Reinecke   2019-04-30  326  	/*
f695ca3886ce72b Christoph Hellwig 2020-07-01  327  	 * The namespace might be going away and the bio might be moved to a
f695ca3886ce72b Christoph Hellwig 2020-07-01  328  	 * different queue via blk_steal_bios(), so we need to use the bio_split
f695ca3886ce72b Christoph Hellwig 2020-07-01  329  	 * pool from the original queue to allocate the bvecs from.
525aa5a705d86e1 Hannes Reinecke   2019-04-30  330  	 */
f695ca3886ce72b Christoph Hellwig 2020-07-01  331  	blk_queue_split(&bio);
7ec9a45fc4ee7fc Jens Axboe        2023-01-04 @332  	if (!bio)
7ec9a45fc4ee7fc Jens Axboe        2023-01-04  333  		return BLK_QC_T_NONE;
525aa5a705d86e1 Hannes Reinecke   2019-04-30  334  
32acab3181c7053 Christoph Hellwig 2017-11-02  335  	srcu_idx = srcu_read_lock(&head->srcu);
32acab3181c7053 Christoph Hellwig 2017-11-02  336  	ns = nvme_find_path(head);
32acab3181c7053 Christoph Hellwig 2017-11-02  337  	if (likely(ns)) {
a7c7f7b2b641bef Christoph Hellwig 2021-01-26  338  		bio_set_dev(bio, ns->disk->part0);
32acab3181c7053 Christoph Hellwig 2017-11-02  339  		bio->bi_opf |= REQ_NVME_MPATH;
1c02fca620f7273 Christoph Hellwig 2020-12-03  340  		trace_block_bio_remap(bio, disk_devt(ns->head->disk),
2796b569591c6f0 Hannes Reinecke   2018-06-07  341  				      bio->bi_iter.bi_sector);
5a6c35f9af41611 Christoph Hellwig 2020-07-01  342  		ret = submit_bio_noacct(bio);
0157ec8dad3c8fc Sagi Grimberg     2019-07-25  343  	} else if (nvme_available_path(head)) {
0157ec8dad3c8fc Sagi Grimberg     2019-07-25  344  		dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
32acab3181c7053 Christoph Hellwig 2017-11-02  345  
32acab3181c7053 Christoph Hellwig 2017-11-02  346  		spin_lock_irq(&head->requeue_lock);
32acab3181c7053 Christoph Hellwig 2017-11-02  347  		bio_list_add(&head->requeue_list, bio);
32acab3181c7053 Christoph Hellwig 2017-11-02  348  		spin_unlock_irq(&head->requeue_lock);
32acab3181c7053 Christoph Hellwig 2017-11-02  349  	} else {
0157ec8dad3c8fc Sagi Grimberg     2019-07-25  350  		dev_warn_ratelimited(dev, "no available path - failing I/O\n");
32acab3181c7053 Christoph Hellwig 2017-11-02  351  
32acab3181c7053 Christoph Hellwig 2017-11-02  352  		bio->bi_status = BLK_STS_IOERR;
32acab3181c7053 Christoph Hellwig 2017-11-02  353  		bio_endio(bio);
32acab3181c7053 Christoph Hellwig 2017-11-02  354  	}
32acab3181c7053 Christoph Hellwig 2017-11-02  355  
32acab3181c7053 Christoph Hellwig 2017-11-02  356  	srcu_read_unlock(&head->srcu, srcu_idx);
32acab3181c7053 Christoph Hellwig 2017-11-02  357  	return ret;
32acab3181c7053 Christoph Hellwig 2017-11-02  358  }
32acab3181c7053 Christoph Hellwig 2017-11-02  359  

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