Re: [PATCH 1/8] Guard bvec iteration logic
From: Ming Lei <tom.leiming@gmail.com>
Date: 2017-03-31 08:21:45
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On Thu, Mar 30, 2017 at 9:49 PM, Dmitry Monakhov [off-list ref] wrote:
quoted hunk ↗ jump to hunk
If some one try to attempt advance bvec beyond it's size we simply dump WARN_ONCE and continue to iterate beyond bvec array boundaries. This simply means that we endup dereferencing/corrupting random memory region. Code was added long time ago here 4550dd6c, luckily no one hit it in real life :) Signed-off-by: Dmitry Monakhov <redacted> --- include/linux/bvec.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 89b65b8..86b914f 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h@@ -70,8 +70,7 @@ static inline void bvec_iter_advance(const struct bio_vec *bv, struct bvec_iter *iter, unsigned bytes) { - WARN_ONCE(bytes > iter->bi_size, - "Attempted to advance past end of bvec iter\n"); + BUG_ON(bytes > iter->bi_size);
This may not a good idea, especially Linus did not like BUG_ON(), please see the following link: https://lkml.org/lkml/2016/10/4/1 Thanks, Ming Lei