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authorDennis Yang <dennisyang@qnap.com>2017-04-18 10:27:06 +0300
committerMike Snitzer <snitzer@redhat.com>2017-04-24 21:58:10 +0300
commit948f581a53b704b984aa20df009f0a2b4cf7f907 (patch)
treebea9d8c3f245895917ec62c122ec28f5beb83c0b /drivers/md/dm-thin.c
parent7d1fedb6e96a960aa91e4ff70714c3fb09195a5a (diff)
downloadlinux-948f581a53b704b984aa20df009f0a2b4cf7f907.tar.xz
dm thin: fix a memory leak when passing discard bio down
dm-thin does not free the discard_parent bio after all chained sub bios finished. The following kmemleak report could be observed after pool with discard_passdown option processes discard bios in linux v4.11-rc7. To fix this, we drop the discard_parent bio reference when its endio (passdown_endio) called. unreferenced object 0xffff8803d6b29700 (size 256): comm "kworker/u8:0", pid 30349, jiffies 4379504020 (age 143002.776s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 01 00 00 00 00 00 00 f0 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff81a5efd9>] kmemleak_alloc+0x49/0xa0 [<ffffffff8114ec34>] kmem_cache_alloc+0xb4/0x100 [<ffffffff8110eec0>] mempool_alloc_slab+0x10/0x20 [<ffffffff8110efa5>] mempool_alloc+0x55/0x150 [<ffffffff81374939>] bio_alloc_bioset+0xb9/0x260 [<ffffffffa018fd20>] process_prepared_discard_passdown_pt1+0x40/0x1c0 [dm_thin_pool] [<ffffffffa018b409>] break_up_discard_bio+0x1a9/0x200 [dm_thin_pool] [<ffffffffa018b484>] process_discard_cell_passdown+0x24/0x40 [dm_thin_pool] [<ffffffffa018b24d>] process_discard_bio+0xdd/0xf0 [dm_thin_pool] [<ffffffffa018ecf6>] do_worker+0xa76/0xd50 [dm_thin_pool] [<ffffffff81086239>] process_one_work+0x139/0x370 [<ffffffff810867b1>] worker_thread+0x61/0x450 [<ffffffff8108b316>] kthread+0xd6/0xf0 [<ffffffff81a6cd1f>] ret_from_fork+0x3f/0x70 [<ffffffffffffffff>] 0xffffffffffffffff Cc: stable@vger.kernel.org Signed-off-by: Dennis Yang <dennisyang@qnap.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-thin.c')
-rw-r--r--drivers/md/dm-thin.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 9b3e2fcbfb1b..f90bcbf24ebc 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1069,6 +1069,7 @@ static void passdown_endio(struct bio *bio)
* to unmap (we ignore err).
*/
queue_passdown_pt2(bio->bi_private);
+ bio_put(bio);
}
static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)