drivers/block/drbd/drbd_worker.c:588 make_resync_request() warn: variable dereferenced before check 'peer_device' (see line 587)

[Dan Carpenter]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   46670259519f4ee4ab378dc014798aabe77c5057
commit: 0d11f3cf279c5ad20a41f29242f170ba3c02f2da drbd: Pass a peer device to the resync and online verify functions
config: parisc-randconfig-m041-20230720 (https://download.01.org/0day-ci/archive/20230721/202307210201.NF8Ro2N0-lkp@xxxxxxxxx/config)
compiler: hppa-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230721/202307210201.NF8Ro2N0-lkp@xxxxxxxxx/reproduce)

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@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202307210201.NF8Ro2N0-lkp@xxxxxxxxx/

smatch warnings:
drivers/block/drbd/drbd_worker.c:588 make_resync_request() warn: variable dereferenced before check 'peer_device' (see line 587)

vim +/peer_device +588 drivers/block/drbd/drbd_worker.c

0d11f3cf279c5a Christoph Böhmwalder 2023-03-30  585  static int make_resync_request(struct drbd_peer_device *const peer_device, int cancel)
b411b3637fa71f Philipp Reisner      2009-09-25  586  {
0d11f3cf279c5a Christoph Böhmwalder 2023-03-30 @587  	struct drbd_device *const device = peer_device->device;
                                                                                           ^^^^^^^^^^^^^
Unchecked dereference

44a4d551846b8c Lars Ellenberg       2013-11-22 @588  	struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL;
                                                                                                   ^^^^^^^^^^^
This check is too late

b411b3637fa71f Philipp Reisner      2009-09-25  589  	unsigned long bit;
b411b3637fa71f Philipp Reisner      2009-09-25  590  	sector_t sector;
155bd9d1abd604 Christoph Hellwig    2020-09-25  591  	const sector_t capacity = get_capacity(device->vdisk);
1816a2b47afae8 Lars Ellenberg       2010-11-11  592  	int max_bio_size;
e65f440d474d7d Lars Ellenberg       2010-11-05  593  	int number, rollback_i, size;
506afb6248af57 Lars Ellenberg       2014-01-31  594  	int align, requeue = 0;
0f0601f4ea2f53 Lars Ellenberg       2010-08-11  595  	int i = 0;
92d94ae66aebda Philipp Reisner      2016-06-14  596  	int discard_granularity = 0;
b411b3637fa71f Philipp Reisner      2009-09-25  597  
b411b3637fa71f Philipp Reisner      2009-09-25  598  	if (unlikely(cancel))

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