> Does the patch below help? > > From: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> > Subject: [PATCH] blk-mq: fix undefined behaviour in order_to_size() > > When this_order variable in blk_mq_init_rq_map() becomes zero > the code incorrectly decrements the variable and passes the result > to order_to_size() helper causing undefined behaviour: > > UBSAN: Undefined behaviour in block/blk-mq.c:1459:27 > shift exponent 4294967295 is too large for 32-bit type 'unsigned int' > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.6.0-rc6-00072-g33656a1 #22 > > Fix the code by checking this_order variable for not having the zero > value first. > > Reported-by: Meelis Roos <mroos@xxxxxxxx> > Fixes: 320ae51feed5 ("blk-mq: new multi-queue block IO queueing mechanism") > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> It fixes the warning independently of the pata driver - ata_piix pata_via pata_serverworks pata_macio 3ware were fixed too. -- Meelis Roos (mroos@xxxxxxxx) -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html