linux-kernel - [PATCH] nvme: fix double blk_mq_complete_request for timeout request with low probability

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Message-ID: <PS1PR03MB4939C825BD5D9A135AA0EB9188919@PS1PR03MB4939.apcprd03.prod.outlook.com>
Date:   Thu, 6 Apr 2023 16:18:18 +0000
From:   Lei Lei2 Yin <yinlei2@...ovo.com>
To:     "kbusch@...nel.org" <kbusch@...nel.org>,
        "axboe@...com" <axboe@...com>, "hch@....de" <hch@....de>,
        Sagi Grimberg <sagi@...mberg.me>
CC:     "linux-nvme@...ts.infradead.org" <linux-nvme@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "cybeyond@...mail.com" <cybeyond@...mail.com>
Subject: [PATCH] nvme: fix double blk_mq_complete_request for timeout request
 with low probability

>From 612bdaa44a8bed09cf8da15df0ad98c018fb5ae4 Mon Sep 17 00:00:00 2001
From: Lei Yin <yinlei2@...ovo.com>
Date: Thu, 6 Apr 2023 23:39:11 +0800
Subject: [PATCH] nvme: fix double blk_mq_complete_request for timeout request
 with low probability

When nvme_cancel_tagset traverses all tagsets and executes
nvme_cancel_request, this request may be executing blk_mq_free_request
that is called by nvme_rdma_complete_timed_out/nvme_tcp_complete_timed_out.
When blk_mq_free_request executes to WRITE_ONCE(rq->state, MQ_RQ_IDLE) and
__blk_mq_free_request(rq), it will cause double blk_mq_complete_request for
this request, and it will cause a null pointer error in the second
execution of this function because rq->mq_hctx has set to NULL in first
execution.

Signed-off-by: Lei Yin <yinlei2@...ovo.com>
---
 drivers/nvme/host/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 53ef028596c6..c1cc384f4f3e 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -450,8 +450,8 @@ bool nvme_cancel_request(struct request *req, void *data)
 	dev_dbg_ratelimited(((struct nvme_ctrl *) data)->device,
 				"Cancelling I/O %d", req->tag);
 
-	/* don't abort one completed request */
-	if (blk_mq_request_completed(req))
+	/* don't abort one completed or idle request */
+	if (blk_mq_rq_state(req) != MQ_RQ_IN_FLIGHT)
 		return true;
 
 	nvme_req(req)->status = NVME_SC_HOST_ABORTED_CMD;
-- 
2.39.1