On Tue, Feb 19, 2019 at 02:37:02PM +0000, Colin King wrote: > From: Colin Ian King <[email protected]> > > The bio pointer is being null checked hence it can be potentially null, > however earlier it is being derefefenced on the assignment of front_seg_size. > Avoid the dereference issue by only assigning front_seg_size after bios has > been null sanity checked. > > Fixes: dcebd755926b ("block: use bio_for_each_bvec() to compute multi-page > bvec count") > Signed-off-by: Colin Ian King <[email protected]> > --- > > V2: remove front_seg_size assignment when it is declared > > --- > block/blk-merge.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index bed065904677..096947413ea9 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -363,7 +363,7 @@ static unsigned int __blk_recalc_rq_segments(struct > request_queue *q, > struct bio_vec bv, bvprv = { NULL }; > int prev = 0; > unsigned int seg_size, nr_phys_segs; > - unsigned front_seg_size = bio->bi_seg_front_size; > + unsigned front_seg_size;
Smatch says bio is non-NULL but I didn't verify by hand. regards, dan carpenter
