Re: [4.1.3-rt8] [report][cpuhotplug] BUG: spinlock bad magic on CPU#0, sh/137

[Thomas Gleixner]

On Fri, 9 Oct 2015, Grygorii Strashko wrote:
> I can constantly see below error report with 4.1 RT-kernel on TI ARM dra7-evm 
> if I'm trying to unplug cpu1:
> 
> [   57.737589] CPU1: shutdown
> [   57.767537] BUG: spinlock bad magic on CPU#0, sh/137
> [   57.767546]  lock: 0xee994730, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0

> It looks like this backtrace was introduces by 
> 
> commit 91df05da13a6c6c358e71182e80f19f3c48d1615
> net: Use skbufhead with raw lock
>
> I see the potential fix for this issue as below: 
> 
> index 4969c0d..f8c23de 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -7217,7 +7217,7 @@ static int dev_cpu_callback(struct notifier_block *nfb,
>                 netif_rx_ni(skb);
>                 input_queue_head_incr(oldsd);
>         }
> -       while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) {
> +       while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {

Your patch is white space damaged ....

>                 netif_rx_ni(skb);
>                 input_queue_head_incr(oldsd);
>         }
> 
> input_pkt_queue is per-cpu queue and at this moment cpu is dead already,
> so no one should touch it. But I'm not sure if my assumption is correct.

It is. Picking it up for the next release

Thanks,

	tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/