From: duoming@zju.edu.cn
To: "James Smart" <jsmart2021@gmail.com>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
james.smart@broadcom.com, kbusch@kernel.org, axboe@fb.com,
hch@lst.de, sagi@grimberg.me
Subject: Re: [PATCH] nvme-fc: fix sleep-in-atomic-context bug caused by nvme_fc_rcv_ls_req
Date: Mon, 3 Oct 2022 09:50:43 +0800 (GMT+08:00) [thread overview]
Message-ID: <7bd9e071.1063f1.1839b89cefa.Coremail.duoming@zju.edu.cn> (raw)
In-Reply-To: <305fbf18-6759-9b00-6fc0-93a4a2e40be2@gmail.com>
Hello,
On Sun, 2 Oct 2022 10:12:15 -0700 James Smart wrote:
> On 10/1/2022 5:19 PM, Duoming Zhou wrote:
> > 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",
>
> I would prefer this was fixed within lpfc rather than introducing atomic
> allocations (1st in either host or target transport). It was introduced
> by lpfc change in irq handling style.
Thank your for your reply and suggestions!
Do you think change the lpfc_poll_timeout() to a delayed_work is better?
Best regards,
Duoming Zhou
next prev parent reply other threads:[~2022-10-03 1:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-02 0:19 [PATCH] nvme-fc: fix sleep-in-atomic-context bug caused by nvme_fc_rcv_ls_req Duoming Zhou
2022-10-02 17:12 ` James Smart
2022-10-03 1:50 ` duoming [this message]
2022-10-03 2:56 ` James Smart
2022-10-03 17:48 ` James Smart
2022-10-04 11:10 ` duoming
2022-10-04 13:51 ` James Smart
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