On Tue, 15 Nov 2011 09:32:39 +0300 Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > Hello NeilBrown, > > This is a semi-automatic email about new static checker warnings. > > The patch e1f6cbf7e1b0: "md/raid10: handle recovery of replacement > devices." from Nov 9, 2011, leads to the following Smatch complaint: > > drivers/md/raid10.c +2814 sync_request() > error: we previously assumed 'bio' could be null (see line 2808) > > drivers/md/raid10.c > 2807 bio = r10_bio->devs[1].repl_bio; > 2808 if (bio) > ^^^ > check. > > 2809 bio->bi_end_io = NULL; > 2810 rdev = mirror->replacement; > 2811 if (rdev == NULL || > 2812 test_bit(Faulty, &rdev->flags)) > 2813 break; > 2814 bio->bi_next = biolist; > ^^^^^^^^^^^^ > unconditional dereference. > > 2815 biolist = bio; > 2816 bio->bi_private = r10_bio; > > regards, > dan carpenter Thanks. I happen to know that if mirror->replacement is not NULL, then conf->have_replacement is true, so r10buf_pool_alloc will have allocated [1].repl_bio so if we get to 2814, bio will definitely be non-NULL. Still, it wouldn't hurt to add a test for 'bio' to keep match happy, and put in a big comment to keep reviewers happy. I'll consider doing that. Thanks, NeilBrown
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