Re: Fw: [Bugme-new] [Bug 4628] New: Test server hang while running rhr (network) test on RHEL4 with kernel 2.6.12-rc1-mm4

[Andrew Morton <akpm@xxxxxxxx>]

Jian Jun He <hejianj@xxxxxxxxxx> wrote:
>
> I download e100-3.4.8 and installed in the test machine (both client and
>  server). But the server still hang while running rhr (network) test. :(

e100 is one of those drivers which we'd rather like to have working properly.

Can we please confirm that a) this bug is not fixed in 2.6.12-rc5 and b)
nobody has seen a patch which fixes it?



For reference:

Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
>
> Andrew Morton <akpm@xxxxxxxx> wrote:
> > 
> > Might be a bug in the e100 driver, might not be.
> > 
> > I assume this is the
> > 
> >        BUG_ON(skb->list != NULL);
> 
> It certainly is a bug in e100.
> 
> e100_tx_timeout -> e100_down -> e100_rx_clean_list
> 
> is racing against
> 
> e100_poll -> e100_rx_clean -> e100_rx_indicate
> 
> e100_rx_clean/e100_rx_indicate takes an skb off the RX ring and
> while it's being processed e100_rx_clean_list comes along and
> frees it.
> 
> >From a quick check similar problems may exist in other drivers that
> have lockless ->poll() functions with RX rings.