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authorTahsin Erdogan <tahsin@google.com>2017-03-10 12:09:49 -0800
committerJens Axboe <axboe@fb.com>2017-03-13 08:27:34 -0600
commit4a3a485b1ed0e109718cc8c9d094fa0f552de9b2 (patch)
tree7e400cfc12120881e18efc4c6da3deefd6e50c3b /fs/fs-writeback.c
parent0067d4b020ea07a58540acb2c5fcd3364bf326e0 (diff)
downloadlinux-4a3a485b1ed0e109718cc8c9d094fa0f552de9b2.tar.bz2
writeback: fix memory leak in wb_queue_work()
When WB_registered flag is not set, wb_queue_work() skips queuing the work, but does not perform the necessary clean up. In particular, if work->auto_free is true, it should free the memory. The leak condition can be reprouced by following these steps: mount /dev/sdb /mnt/sdb /* In qemu console: device_del sdb */ umount /dev/sdb Above will result in a wb_queue_work() call on an unregistered wb and thus leak memory. Reported-by: John Sperbeck <jsperbeck@google.com> Signed-off-by: Tahsin Erdogan <tahsin@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c35
1 files changed, 21 insertions, 14 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index ef600591d96f..63ee2940775c 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -173,19 +173,33 @@ static void wb_wakeup(struct bdi_writeback *wb)
spin_unlock_bh(&wb->work_lock);
}
+static void finish_writeback_work(struct bdi_writeback *wb,
+ struct wb_writeback_work *work)
+{
+ struct wb_completion *done = work->done;
+
+ if (work->auto_free)
+ kfree(work);
+ if (done && atomic_dec_and_test(&done->cnt))
+ wake_up_all(&wb->bdi->wb_waitq);
+}
+
static void wb_queue_work(struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
trace_writeback_queue(wb, work);
- spin_lock_bh(&wb->work_lock);
- if (!test_bit(WB_registered, &wb->state))
- goto out_unlock;
if (work->done)
atomic_inc(&work->done->cnt);
- list_add_tail(&work->list, &wb->work_list);
- mod_delayed_work(bdi_wq, &wb->dwork, 0);
-out_unlock:
+
+ spin_lock_bh(&wb->work_lock);
+
+ if (test_bit(WB_registered, &wb->state)) {
+ list_add_tail(&work->list, &wb->work_list);
+ mod_delayed_work(bdi_wq, &wb->dwork, 0);
+ } else
+ finish_writeback_work(wb, work);
+
spin_unlock_bh(&wb->work_lock);
}
@@ -1873,16 +1887,9 @@ static long wb_do_writeback(struct bdi_writeback *wb)
set_bit(WB_writeback_running, &wb->state);
while ((work = get_next_work_item(wb)) != NULL) {
- struct wb_completion *done = work->done;
-
trace_writeback_exec(wb, work);
-
wrote += wb_writeback(wb, work);
-
- if (work->auto_free)
- kfree(work);
- if (done && atomic_dec_and_test(&done->cnt))
- wake_up_all(&wb->bdi->wb_waitq);
+ finish_writeback_work(wb, work);
}
/*