From: Chas Williams <3ch...@gmail.com>
Date: Sat, 11 Mar 2017 19:41:36 -0500
> From: Francois Romieu <rom...@fr.zoreil.com>
>
> Andrey reported this kernel warning:
>
> WARNING: CPU: 0 PID: 4114 at kernel/sched/core.c:7737
> __might_sleep+0x149/0x1a0
> do not call blocking ops when !TASK_RUNNING; state=1 set at
> [<ffffffff813fcb22>] prepare_to_wait+0x182/0x530
>
> The deeply nested alloc_skb is a problem.
>
> Diagnosis: nesting is wrong. It makes zero sense. Fix it and the
> implicit task state change problem automagically goes away.
>
> alloc_skb() does not need to be in the "while" loop.
>
> alloc_skb() does not need to be in the {prepare_to_wait/add_wait_queue ...
> finish_wait/remove_wait_queue} block.
>
> I claim that:
> - alloc_tx() should only perform the "wait_for_decent_tx_drain" part
> - alloc_skb() ought to be done directly in vcc_sendmsg
> - alloc_skb() failure can be handled gracefully in vcc_sendmsg
> - alloc_skb() may use a (m->msg_flags & MSG_DONTWAIT) dependent
> GFP_{KERNEL / ATOMIC} flag
>
> Reported-by: Andrey Konovalov <andreyk...@google.com>
> Reviewed-and-Tested-by: Chas Williams <3ch...@gmail.com>
> Signed-off-by: Chas Williams <3ch...@gmail.com>
Applied, thanks a lot Chas.
