Re: [PATCH v2] PCI: take the rescan lock when adding devices during host probe

[Bartosz Golaszewski]

On Thu, Oct 3, 2024 at 10:43 AM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
>
> From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
>
> Since adding the PCI power control code, we may end up with a race
> between the pwrctl platform device rescanning the bus and the host
> controller probe function. The latter needs to take the rescan lock when
> adding devices or we may end up in an undefined state having two
> incompletely added devices and hit the following crash when trying to
> remove the device over sysfs:
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> Internal error: Oops: 0000000096000004 [#1] SMP
> Call trace:
>   __pi_strlen+0x14/0x150
>   kernfs_find_ns+0x80/0x13c
>   kernfs_remove_by_name_ns+0x54/0xf0
>   sysfs_remove_bin_file+0x24/0x34
>   pci_remove_resource_files+0x3c/0x84
>   pci_remove_sysfs_dev_files+0x28/0x38
>   pci_stop_bus_device+0x8c/0xd8
>   pci_stop_bus_device+0x40/0xd8
>   pci_stop_and_remove_bus_device_locked+0x28/0x48
>   remove_store+0x70/0xb0
>   dev_attr_store+0x20/0x38
>   sysfs_kf_write+0x58/0x78
>   kernfs_fop_write_iter+0xe8/0x184
>   vfs_write+0x2dc/0x308
>   ksys_write+0x7c/0xec
>
> Reported-by: Konrad Dybcio <konradybcio@xxxxxxxxxx>
> Tested-by: Konrad Dybcio <konradybcio@xxxxxxxxxx>
> Fixes: 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> ---

It's been a week, so gentle ping - can this be picked up into v6.12?

Thanks,
Bartosz