Re: [PATCH net v2 7/7] net: hibmcge: fix multiple phy_stop() issue

[Simon Horman <horms@kernel.org>]

On Thu, Apr 03, 2025 at 09:53:11PM +0800, Jijie Shao wrote:
> After detecting the np_link_fail exception,
> the driver attempts to fix the exception by
> using phy_stop() and phy_start() in the scheduled task.
> 
> However, hbg_fix_np_link_fail() and .ndo_stop()
> may be concurrently executed. As a result,
> phy_stop() is executed twice, and the following Calltrace occurs:
> 
>  hibmcge 0000:84:00.2 enp132s0f2: Link is Down
>  hibmcge 0000:84:00.2: failed to link between MAC and PHY, try to fix...
>  ------------[ cut here ]------------
>  called from state HALTED
>  WARNING: CPU: 71 PID: 23391 at drivers/net/phy/phy.c:1503 phy_stop...
>  ...
>  pc : phy_stop+0x138/0x180
>  lr : phy_stop+0x138/0x180
>  sp : ffff8000c76bbd40
>  x29: ffff8000c76bbd40 x28: 0000000000000000 x27: 0000000000000000
>  x26: ffff2020047358c0 x25: ffff202004735940 x24: ffff20200000e405
>  x23: ffff2020060e5178 x22: ffff2020060e4000 x21: ffff2020060e49c0
>  x20: ffff2020060e5170 x19: ffff20202538e000 x18: 0000000000000020
>  x17: 0000000000000000 x16: ffffcede02e28f40 x15: ffffffffffffffff
>  x14: 0000000000000000 x13: 205d313933333254 x12: 5b5d393430303233
>  x11: ffffcede04555958 x10: ffffcede04495918 x9 : ffffcede0274fee0
>  x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : 0000000000000001
>  x5 : 00000000002bffa8 x4 : 0000000000000000 x3 : 0000000000000000
>  x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff20202e429480
>  Call trace:
>   phy_stop+0x138/0x180
>   hbg_fix_np_link_fail+0x4c/0x90 [hibmcge]
>   hbg_service_task+0xfc/0x148 [hibmcge]
>   process_one_work+0x180/0x398
>   worker_thread+0x210/0x328
>   kthread+0xe0/0xf0
>   ret_from_fork+0x10/0x20
>  ---[ end trace 0000000000000000 ]---
> 
> This patch adds the rtnl_lock to hbg_fix_np_link_fail()
> to ensure that other operations are not performed concurrently.
> In addition, np_link_fail exception can be fixed
> only when the PHY is link.
> 
> Fixes: e0306637e85d ("net: hibmcge: Add support for mac link exception handling feature")
> Signed-off-by: Jijie Shao <shaojijie@huawei.com>

Reviewed-by: Simon Horman <horms@kernel.org>