On Fri, Oct 04, 2024 at 03:33:00PM +0100, John Garry wrote: > On 04/10/2024 15:10, SurajSonawane2415 wrote: > > Explaination of how bio could be used uninitialized in this function: > > > > In the function blk_rq_prep_clone, the variable bio is declared but can remain uninitialized > > if the allocation with bio_alloc_clone fails. This can lead to undefined behavior when the > > function attempts to free bio in the error handling section using bio_put(bio). > > By initializing bio to NULL at declaration, we ensure that the cleanup code will only > > interact with bio if it has been successfully allocated. > > > > > > What about if rq_src->bio is NULL for blk_rq_prep_clone() -> > __rq_for_each_bio(,rq_src): > > #define __rq_for_each_bio(_bio, rq) \ > if ((rq->bio)) \ > for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next) > > Then I don't think bio it get init'ed. Whether this is possible (rq_src->bio > is NULL) is another question. If the source request doesn't have a bio, then the onstack 'bio' is never referenced, so should be okay if it's not initialized in that case.
