On 10/12/21 5:15 AM, Srinivas Kandagatla wrote:
> Slave pointer is invalid after end of list iteration, using this
> would result in below Memory abort.
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
> ...
> Call trace:
> __dev_printk+0x34/0x7c
> _dev_warn+0x6c/0x90
> sdw_bus_exit_clk_stop+0x194/0x1d0
> swrm_runtime_resume+0x13c/0x238
> pm_generic_runtime_resume+0x2c/0x48
> __rpm_callback+0x44/0x150
> rpm_callback+0x6c/0x78
> rpm_resume+0x314/0x558
> rpm_resume+0x378/0x558
> rpm_resume+0x378/0x558
> __pm_runtime_resume+0x3c/0x88
>
> Use bus->dev instead to print this error message.
>
> Fixes: b50bb8ba369cd ("soundwire: bus: handle -ENODATA errors in clock stop/start sequences")
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Nice catch, even if the 'slave' pointer was valid it makes no sense to
use this device for a bus-level operation. Using the bus->dev is the
right thing to do.
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> ---
> drivers/soundwire/bus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
> index 1b115734a8f6..67369e941d0d 100644
> --- a/drivers/soundwire/bus.c
> +++ b/drivers/soundwire/bus.c
> @@ -1110,7 +1110,7 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
> if (!simple_clk_stop) {
> ret = sdw_bus_wait_for_clk_prep_deprep(bus, SDW_BROADCAST_DEV_NUM);
> if (ret < 0)
> - dev_warn(&slave->dev, "clock stop deprepare wait failed:%d\n", ret);
> + dev_warn(bus->dev, "clock stop deprepare wait failed:%d\n", ret);
> }
>
> list_for_each_entry(slave, &bus->slaves, node) {
>
