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block: call bio_uninit in bio_endio
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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_uninit 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.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Shaohua Li authored and Jens Axboe committed Jul 10, 2017
1 parent 459bd0d commit b222dd2
Showing 1 changed file with 2 additions and 0 deletions.
2 changes: 2 additions & 0 deletions block/bio.c
Original file line number Diff line number Diff line change
Expand Up @@ -1833,6 +1833,8 @@ void bio_endio(struct bio *bio)
}

blk_throtl_bio_endio(bio);
/* release cgroup info */
bio_uninit(bio);
if (bio->bi_end_io)
bio->bi_end_io(bio);
}
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