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authorJens Axboe <axboe@fb.com>2014-12-12 08:53:40 -0700
committerJens Axboe <axboe@fb.com>2014-12-12 08:53:40 -0700
commit849c6e7746e4f6317ace6aa7d2fcdcd844e99ddb (patch)
treea46e807ce51483393beb9e1d8c1ed331e9a023ca /drivers/block
parentfe54303ee2be293c1c5c7a53a152453789cabc2f (diff)
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NVMe: fix race condition in nvme_submit_sync_cmd()
If we have a race between the schedule timing out and the command completing, we could have the task issuing the command exit nvme_submit_sync_cmd() while the irq is running sync_completion(). If that happens, we could be corrupting memory, since the stack that held 'cmdinfo' is no longer valid. Fix this by always calling nvme_abort_cmd_info(). Once that call completes, we know that we have either run sync_completion() if the completion came in, or that we will never run it since we now have special_completion() as the command callback handler. Acked-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/nvme-core.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index e92bdf4c68fc..b1d5d8797315 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -804,12 +804,19 @@ static int nvme_submit_sync_cmd(struct request *req, struct nvme_command *cmd,
nvme_finish_cmd(nvmeq, req->tag, NULL);
set_current_state(TASK_RUNNING);
}
- schedule_timeout(timeout);
+ ret = schedule_timeout(timeout);
- if (cmdinfo.status == -EINTR) {
- nvme_abort_cmd_info(nvmeq, blk_mq_rq_to_pdu(req));
+ /*
+ * Ensure that sync_completion has either run, or that it will
+ * never run.
+ */
+ nvme_abort_cmd_info(nvmeq, blk_mq_rq_to_pdu(req));
+
+ /*
+ * We never got the completion
+ */
+ if (cmdinfo.status == -EINTR)
return -EINTR;
- }
if (result)
*result = cmdinfo.result;
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