bio_free isn't a good place to free cgroup info. There are a lot of cases bio is allocated in special way (for example, in stack) and never gets called by bio_put hence bio_free, we are leaking memory. This patch moves the free to bio endio, which should be called anyway. The __bio_free call in bio_free is kept, in case the bio never gets called bio endio.
This assumes ->bi_end_io() doesn't access cgroup info, which seems true in my audit. This along with Christoph's integrity patch should fix the memory leak issue. Signed-off-by: Shaohua Li <[email protected]> --- block/bio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/bio.c b/block/bio.c index 9cf98b2..e8cda9c 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1828,6 +1828,8 @@ void bio_endio(struct bio *bio) } blk_throtl_bio_endio(bio); + /* release cgroup info */ + __bio_free(bio); if (bio->bi_end_io) bio->bi_end_io(bio); } -- 2.9.3
