Re: [RFC PATCH] PCI/ASPM: Handle missing link state in sysfs reads

[sashiko-bot@kernel.org]

> From: Louis H. Poulin II <poulin.louis@student.oaklandcc.edu>
> 
> InputPlumber can hit a NULL pointer dereference at l0s_aspm_show()
> while reading PCIe sysfs attributes on an ASUS TUF GAMING X870-PLUS
> WIFI. The same fault was seen on downstream OGC kernels
> 7.2.9-ogc3.1.fc44 and 7.2.15-ogc1.1.fc45. The latter logged:
> 
>   BUG: kernel NULL pointer dereference, address: 0000000000000030
>   RIP: 0010:l0s_aspm_show+0x47/0x80
>     dev_attr_show+0x1f/0x50
>     sysfs_kf_seq_show+0xa8/0x110
>     seq_read_iter+0x132/0x4c0
> 
> The faulting instruction reads at offset 0x30 with a NULL base
> register, consistent with accessing the ASPM state through a NULL
> [ ... ]
> ZhaoJinming previously proposed NULL checks for the ASPM and clock
> power-management sysfs callbacks.
> 
> Link: https://lkml.iu.edu/hypermail/linux/kernel/2607.3/04295.html
> Signed-off-by: Louis H. Poulin II <poulin.louis@student.oaklandcc.edu>

Sashiko has reviewed this patch and found no issues.

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