Re: [PATCH wireless] wifi: wilc1000: unregister wiphy only if it has been registered

[Kalle Valo <kvalo@kernel.org>]

Marek Vasut <marex@denx.de> writes:

> On 12/23/24 4:46 PM, Alexis Lothoré wrote:
>
>> There is a specific error path in probe functions in wilc drivers (both
>> sdio and spi) which can lead to kernel panic, as this one for example
>> when using SPI:
>> Unable to handle kernel paging request at virtual address 9f000000
>> when read
>> [9f000000] *pgd=00000000
>> Internal error: Oops: 5 [#1] ARM
>> Modules linked in: wilc1000_spi(+) crc_itu_t crc7 wilc1000 cfg80211 bluetooth ecdh_generic ecc
>> CPU: 0 UID: 0 PID: 106 Comm: modprobe Not tainted 6.13.0-rc3+ #22
>> Hardware name: Atmel SAMA5
>> PC is at wiphy_unregister+0x244/0xc40 [cfg80211]
>> LR is at wiphy_unregister+0x1c0/0xc40 [cfg80211]
>> [...]
>>   wiphy_unregister [cfg80211] from wilc_netdev_cleanup+0x380/0x494 [wilc1000]
>>   wilc_netdev_cleanup [wilc1000] from wilc_bus_probe+0x360/0x834 [wilc1000_spi]
>>   wilc_bus_probe [wilc1000_spi] from spi_probe+0x15c/0x1d4
>>   spi_probe from really_probe+0x270/0xb2c
>>   really_probe from __driver_probe_device+0x1dc/0x4e8
>>   __driver_probe_device from driver_probe_device+0x5c/0x140
>>   driver_probe_device from __driver_attach+0x220/0x540
>>   __driver_attach from bus_for_each_dev+0x13c/0x1a8
>>   bus_for_each_dev from bus_add_driver+0x2a0/0x6a4
>>   bus_add_driver from driver_register+0x27c/0x51c
>>   driver_register from do_one_initcall+0xf8/0x564
>>   do_one_initcall from do_init_module+0x2e4/0x82c
>>   do_init_module from load_module+0x59a0/0x70c4
>>   load_module from init_module_from_file+0x100/0x148
>>   init_module_from_file from sys_finit_module+0x2fc/0x924
>>   sys_finit_module from ret_fast_syscall+0x0/0x1c
>> The issue can easily be reproduced, for example by not wiring
>> correctly
>> a wilc device through SPI (and so, make it unresponsive to early SPI
>> commands). It is due to a recent change decoupling wiphy allocation from
>> wiphy registration, however wilc_netdev_cleanup has not been updated
>> accordingly, letting it possibly call wiphy unregister on a wiphy which
>> has never been registered.
>> Fix this crash by moving wiphy_unregister/wiphy_free out of
>> wilc_netdev_cleanup, and by adjusting error paths in both drivers
>> Fixes: fbdf0c5248dc ("wifi: wilc1000: Register wiphy after reading
>> out chipid")
>> Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
> Nice find, thank you for fixing it.
>
> Reviewed-by: Marek Vasut <marex@denx.de>

We are quite late in the cycle so I think I'll queue this to
wireless-next for v6.14.

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