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Date: Tue, 8 Aug 2023 21:41:16 +0300
From: Leon Romanovsky <leon@...nel.org>
To: Jijie Shao <shaojijie@...wei.com>
Cc: yisen.zhuang@...wei.com, salil.mehta@...wei.com,
davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, shenjian15@...wei.com, wangjie125@...wei.com,
liuyonglong@...wei.com, wangpeiyang1@...wei.com,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 net 4/4] net: hns3: fix deadlock issue when
externel_lb and reset are executed together
On Mon, Aug 07, 2023 at 07:34:52PM +0800, Jijie Shao wrote:
> From: Yonglong Liu <liuyonglong@...wei.com>
>
> When externel_lb and reset are executed together, a deadlock may
> occur:
> [ 3147.217009] INFO: task kworker/u321:0:7 blocked for more than 120 seconds.
> [ 3147.230483] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 3147.238999] task:kworker/u321:0 state:D stack: 0 pid: 7 ppid: 2 flags:0x00000008
> [ 3147.248045] Workqueue: hclge hclge_service_task [hclge]
> [ 3147.253957] Call trace:
> [ 3147.257093] __switch_to+0x7c/0xbc
> [ 3147.261183] __schedule+0x338/0x6f0
> [ 3147.265357] schedule+0x50/0xe0
> [ 3147.269185] schedule_preempt_disabled+0x18/0x24
> [ 3147.274488] __mutex_lock.constprop.0+0x1d4/0x5dc
> [ 3147.279880] __mutex_lock_slowpath+0x1c/0x30
> [ 3147.284839] mutex_lock+0x50/0x60
> [ 3147.288841] rtnl_lock+0x20/0x2c
> [ 3147.292759] hclge_reset_prepare+0x68/0x90 [hclge]
> [ 3147.298239] hclge_reset_subtask+0x88/0xe0 [hclge]
> [ 3147.303718] hclge_reset_service_task+0x84/0x120 [hclge]
> [ 3147.309718] hclge_service_task+0x2c/0x70 [hclge]
> [ 3147.315109] process_one_work+0x1d0/0x490
> [ 3147.319805] worker_thread+0x158/0x3d0
> [ 3147.324240] kthread+0x108/0x13c
> [ 3147.328154] ret_from_fork+0x10/0x18
>
> In externel_lb process, the hns3 driver call napi_disable()
> first, then the reset happen, then the restore process of the
> externel_lb will fail, and will not call napi_enable(). When
> doing externel_lb again, napi_disable() will be double call,
> cause a deadlock of rtnl_lock().
>
> This patch use the HNS3_NIC_STATE_DOWN state to protect the
> calling of napi_disable() and napi_enable() in externel_lb
> process, just as the usage in ndo_stop() and ndo_start().
>
> Fixes: 04b6ba143521 ("net: hns3: add support for external loopback test")
> Signed-off-by: Yonglong Liu <liuyonglong@...wei.com>
> Signed-off-by: Jijie Shao <shaojijie@...wei.com>
> ---
> drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
Thanks,
Reviewed-by: Leon Romanovsky <leonro@...dia.com>
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