From a00ebd1cf12c378a1d4f7a1d6daf1d76c1eaad82 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Thu, 11 May 2017 10:21:46 +0200 Subject: [PATCH] drbd: fix request leak introduced by locking/atomic, kref: Kill kref_sub() When killing kref_sub(), the unconditional additional kref_get() was not properly paired with the necessary kref_put(), causing a leak of struct drbd_requests (~ 224 Bytes) per submitted bio, and breaking DRBD in general, as the destructor of those "drbd_requests" does more than just the mempoll_free(). Fixes: bdfafc4ffdd2 ("locking/atomic, kref: Kill kref_sub()") Signed-off-by: Lars Ellenberg Cc: stable@vger.kernel.org # v4.11 Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_req.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index b5730e17b455..656624314f0d 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -315,24 +315,32 @@ void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m) } /* still holds resource->req_lock */ -static int drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put) +static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put) { struct drbd_device *device = req->device; D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED)); + if (!put) + return; + if (!atomic_sub_and_test(put, &req->completion_ref)) - return 0; + return; drbd_req_complete(req, m); + /* local completion may still come in later, + * we need to keep the req object around. */ + if (req->rq_state & RQ_LOCAL_ABORTED) + return; + if (req->rq_state & RQ_POSTPONED) { /* don't destroy the req object just yet, * but queue it for retry */ drbd_restart_request(req); - return 0; + return; } - return 1; + kref_put(&req->kref, drbd_req_destroy); } static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) @@ -519,12 +527,8 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m, if (req->i.waiting) wake_up(&device->misc_wait); - if (c_put) { - if (drbd_req_put_completion_ref(req, m, c_put)) - kref_put(&req->kref, drbd_req_destroy); - } else { - kref_put(&req->kref, drbd_req_destroy); - } + drbd_req_put_completion_ref(req, m, c_put); + kref_put(&req->kref, drbd_req_destroy); } static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req) @@ -1366,8 +1370,7 @@ nodata: } out: - if (drbd_req_put_completion_ref(req, &m, 1)) - kref_put(&req->kref, drbd_req_destroy); + drbd_req_put_completion_ref(req, &m, 1); spin_unlock_irq(&resource->req_lock); /* Even though above is a kref_put(), this is safe.