Re: [PATCH 3/5] PCI/ERR: get device before call device driver to avoid null pointer reference

[Andy Shevchenko]

On Thu, Sep 24, 2020 at 10:34:21PM -0400, Ethan Zhao wrote:
> During DPC error injection test we found there is race condition between
> pciehp and DPC driver, null pointer reference caused panic as following

null -> NULL

> 
>  # setpci -s 64:02.0 0x196.w=000a
>   // 64:02.0 is rootport has DPC capability
>  # setpci -s 65:00.0 0x04.w=0544
>   // 65:00.0 is NVMe SSD populated in above port
>  # mount /dev/nvme0n1p1 nvme
> 
>  (tested on stable 5.8 & ICX platform)
> 
>  Buffer I/O error on dev nvme0n1p1, logical block 468843328,
>  async page read
>  BUG: kernel NULL pointer dereference, address: 0000000000000050
>  #PF: supervisor read access in kernel mode
>  #PF: error_code(0x0000) - not-present page

Same comment about Oops.

-- 
With Best Regards,
Andy Shevchenko