Re: [PATCH V3] firmware loader: Fix the race FW_STATUS_DONE isfollowed by class_timeout

[Ming Lei]

On Thu, Nov 8, 2012 at 7:14 PM, Chuansheng Liu <chuansheng.liu@xxxxxxxxx> wrote:
>
> There is a race as below when calling request_firmware():
> CPU1                                   CPU2
> write 0 > loading
> mutex_lock(&fw_lock)
> ...
> set_bit FW_STATUS_DONE                 class_timeout is coming
>                                        set_bit FW_STATUS_ABORT
> complete_all &completion
> ...
> mutex_unlock(&fw_lock)
>
> In this time, the bit FW_STATUS_DONE and FW_STATUS_ABORT are set,
> and request_firmware() will return failure due to condition in
> _request_firmware_load():
>         if (!buf->size || test_bit(FW_STATUS_ABORT, &buf->status))
>                 retval = -ENOENT;
>
> But from the above scenerio, it should be a successful requesting.
> So we need judge if the bit FW_STATUS_DONE is already set before
> calling fw_load_abort() in timeout function.
>
> As Ming's proposal, we need change the timer into sched_work to
> benefit from using &fw_lock mutex also.
>
> Signed-off-by: liu chuansheng <chuansheng.liu@xxxxxxxxx>

Acked-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>

Thanks,
--
Ming Lei
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