From: Xiao Ni Subject: Re: [PATCH] md: fix memleak for mempool Date: Fri, 19 Oct 2018 10:41:40 -0400 (EDT) Message-ID: <1488114196.22211692.1539960100628.JavaMail.zimbra@redhat.com> References: <1539958891-12412-1-git-send-email-jinpuwang@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1539958891-12412-1-git-send-email-jinpuwang@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Jack Wang Cc: shli@fb.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, Jack Wang List-Id: linux-raid.ids ----- Original Message ----- > From: "Jack Wang" > To: shli@fb.com, linux-raid@vger.kernel.org > Cc: xni@redhat.com, linux-kernel@vger.kernel.org, "Jack Wang" > Sent: Friday, October 19, 2018 10:21:31 PM > Subject: [PATCH] md: fix memleak for mempool > > From: Jack Wang > > I noticed kmemleak report memory leak when run create/stop > md in a loop, backtrace: > [<000000001ca975e7>] mempool_create_node+0x86/0xd0 > [<0000000095576bcd>] md_run+0x1057/0x1410 [md_mod] > [<000000007b45c5fc>] do_md_run+0x15/0x130 [md_mod] > [<000000001ede9ec0>] md_ioctl+0x1f49/0x25d0 [md_mod] > [<000000004142cacf>] blkdev_ioctl+0x680/0xd00 > > The root cause is we alloc mddev->flush_pool and > mddev->flush_bio_pool in md_run, but from do_md_stop > will not call into md_stop but __md_stop, move the > mempool_destroy to __md_stop fixes the problem for me. > > The bug was introduced in 5a409b4f56d5, the fixes should go to > 4.18+ > > Cc: Xiao Ni > Fixes: 5a409b4f56d5 ("MD: fix lock contention for flush bios") > Signed-off-by: Jack Wang > --- > drivers/md/md.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > > diff --git a/drivers/md/md.c b/drivers/md/md.c > index 4c0f3e0331d5..feb6145097da 100644 > --- a/drivers/md/md.c > +++ b/drivers/md/md.c > @@ -5904,14 +5904,6 @@ static void __md_stop(struct mddev *mddev) > mddev->to_remove = &md_redundancy_group; > module_put(pers->owner); > clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); > -} > - > -void md_stop(struct mddev *mddev) > -{ > - /* stop the array and free an attached data structures. > - * This is called from dm-raid > - */ > - __md_stop(mddev); > if (mddev->flush_bio_pool) { > mempool_destroy(mddev->flush_bio_pool); > mddev->flush_bio_pool = NULL; > @@ -5920,6 +5912,14 @@ void md_stop(struct mddev *mddev) > mempool_destroy(mddev->flush_pool); > mddev->flush_pool = NULL; > } > +} > + > +void md_stop(struct mddev *mddev) > +{ > + /* stop the array and free an attached data structures. > + * This is called from dm-raid > + */ > + __md_stop(mddev); > bioset_exit(&mddev->bio_set); > bioset_exit(&mddev->sync_set); > } > -- > 2.7.4 > > Reviewed-by: Xiao Ni