ACK: [SRU] [Bionic] [PATCH 1/1] thunderbolt: Prevent crash when ICM firmware is not running

[Kleber Souza]

On 05/03/18 07:13, Kai-Heng Feng wrote:
> From: Mika Westerberg <mika.westerberg at linux.intel.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1768292
> 
> 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 at protonmail.ch>
> Signed-off-by: Mika Westerberg <mika.westerberg at linux.intel.com>
> Acked-by: Yehezkel Bernat <yehezkel.bernat at intel.com>
> Cc: stable at vger.kernel.org
> (cherry picked from commit ea9d7bb798900096f26c585957d6ad9c532417e6)
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>

Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>

> ---
>  drivers/thunderbolt/icm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
> index 6b1041677604..2d2ceda9aa26 100644
> --- a/drivers/thunderbolt/icm.c
> +++ b/drivers/thunderbolt/icm.c
> @@ -1452,6 +1452,9 @@ static int icm_firmware_reset(struct tb *tb, struct tb_nhi *nhi)
>  	struct icm *icm = tb_priv(tb);
>  	u32 val;
>  
> +	if (!icm->upstream_port)
> +		return -ENODEV;
> +
>  	/* Put ARC to wait for CIO reset event to happen */
>  	val = ioread32(nhi->iobase + REG_FW_STS);
>  	val |= REG_FW_STS_CIO_RESET_REQ;
>