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From:   Duoming Zhou <duoming@zju.edu.cn>
To:     linux-nvme@lists.infradead.org
Cc:     linux-kernel@vger.kernel.org, james.smart@broadcom.com,
        kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me,
        Duoming Zhou <duoming@zju.edu.cn>
Subject: [PATCH] nvme-fc: fix sleep-in-atomic-context bug caused by nvme_fc_rcv_ls_req
Date:   Sun,  2 Oct 2022 08:19:09 +0800
Message-Id: <20221002001909.20070-1-duoming@zju.edu.cn>
Precedence: bulk

The function lpfc_poll_timeout() is a timer handler that runs in an
atomic context, but it calls "kzalloc(.., GFP_KERNEL)" that may sleep.
As a result, the sleep-in-atomic-context bug will happen. The processes
is shown below:

lpfc_poll_timeout()
 lpfc_sli_handle_fast_ring_event()
  lpfc_sli_process_unsol_iocb()
   lpfc_complete_unsol_iocb()
    lpfc_nvme_unsol_ls_handler()
     lpfc_nvme_handle_lsreq()
      nvme_fc_rcv_ls_req()
       kzalloc(sizeof(.., GFP_KERNEL) //may sleep

This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to
GFP_ATOMIC in order to mitigate the bug.

Fixes: 14fd1e98afaf ("nvme-fc: Add Disconnect Association Rcv support")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
 drivers/nvme/host/fc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 127abaf9ba5..36698dfc8b3 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1754,7 +1754,7 @@ nvme_fc_rcv_ls_req(struct nvme_fc_remote_port *portptr,
 	lsop = kzalloc(sizeof(*lsop) +
 			sizeof(union nvmefc_ls_requests) +
 			sizeof(union nvmefc_ls_responses),
-			GFP_KERNEL);
+			GFP_ATOMIC);
 	if (!lsop) {
 		dev_info(lport->dev,
 			"RCV %s LS failed: No memory\n",
-- 
2.17.1