| Message ID | 22191628.vH7YQZ1hRO@amdc1976 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> Does the patch below help? Yes, the warning is gone and I see not other errors. There is nothing attached to pata_amd so I do not know if it works too. > > From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> > 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@linux.ee> > Fixes: 320ae51feed5 ("blk-mq: new multi-queue block IO queueing mechanism") > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> > --- > block/blk-mq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 0c2ed83..7df9c92 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -1495,7 +1495,7 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, > int to_do; > void *p; > > - while (left < order_to_size(this_order - 1) && this_order) > + while (this_order && left < order_to_size(this_order - 1)) > this_order--; > > do { >
On 05/13/2016 09:31 AM, Bartlomiej Zolnierkiewicz wrote: > Does the patch below help? > > From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> > 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. Thanks Bart, added for 4.7.
> Does the patch below help? > > From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> > 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@linux.ee> > Fixes: 320ae51feed5 ("blk-mq: new multi-queue block IO queueing mechanism") > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> It fixes the warning independently of the pata driver - ata_piix pata_via pata_serverworks pata_macio 3ware were fixed too.
diff --git a/block/blk-mq.c b/block/blk-mq.c index 0c2ed83..7df9c92 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1495,7 +1495,7 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, int to_do; void *p; - while (left < order_to_size(this_order - 1) && this_order) + while (this_order && left < order_to_size(this_order - 1)) this_order--; do {