Re: [PATCH] thunderbolt: Prevent crash when ICM firmware is not running

[Mika Westerberg]

On Fri, Mar 09, 2018 at 01:44:34PM +0300, Mika Westerberg wrote:
> On Lenovo ThinkPad Yoga 370 (and possibly some other Lenovo models as
> well) the Thunderbolt host controller sometimes comes up in such way
> that the ICM firmware is not running properly. This is most likely an
> issue in BIOS/firmware but as side-effect driver crashes the kernel due
> to NULL pointer dereference:
> 
>   BUG: unable to handle kernel NULL pointer dereference at 0000000000000980
>   IP: pci_write_config_dword+0x5/0x20
>   Call Trace:
>    pcie2cio_write+0x3b/0x70 [thunderbolt]
>    icm_driver_ready+0x168/0x260 [thunderbolt]
>    ? tb_ctl_start+0x50/0x70 [thunderbolt]
>    tb_domain_add+0x73/0xf0 [thunderbolt]
>    nhi_probe+0x182/0x300 [thunderbolt]
>    local_pci_probe+0x42/0xa0
>    ? pci_match_device+0xd9/0x100
>    pci_device_probe+0x146/0x1b0
>    driver_probe_device+0x315/0x480
>    ...
> 
> Instead of crashing update the driver to bail out gracefully if we
> encounter such situation.
> 
> Fixes: f67cf491175a ("thunderbolt: Add support for Internal Connection Manager (ICM)")
> Reported-by: Jordan Glover <Golden_Miller83@xxxxxxxxxxxxx>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

Applied to thunderbolt.git/next.