Messages in this thread Patch in this message | | | Date | Sat, 29 Jun 2013 09:31:54 -0700 | From | Ben Greear <> | Subject | Re: kernel panic in skb_copy_bits |
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On 06/29/2013 09:26 AM, Eric Dumazet wrote: > On Sat, 2013-06-29 at 09:11 -0700, Ben Greear wrote: > >> Do you know if your patch should go in 3.9? >> > > Yes it should.
Ok, I'll add that to my tree.
>> Your test case sounds a bit like what gives us the rare crash in tcp_collapse >> (we have lots of bouncing wifi interfaces running slow-speed TCP trafic). But, >> it takes days for us to hit the problem most of the time. > > Well, unfortunately that's a different problem :(
For what it's worth, I added this patch to my tree. We haven't hit the problem since, but perhaps on the over-the-weekend run we'll see it.
commit 0286716b36a0e5b82c385052a0971f44bc3c3442 Author: Ben Greear <greearb@candelatech.com> Date: Tue Jun 25 15:49:52 2013 -0700
tcp: Try to work around crash in tcp_collapse.
And print out some info about why it crashed.
Signed-off-by: Ben Greear <greearb@candelatech.com>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a2f267a..63f7704 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4810,7 +4810,15 @@ restart: int offset = start - TCP_SKB_CB(skb)->seq; int size = TCP_SKB_CB(skb)->end_seq - start;
- BUG_ON(offset < 0); + if (WARN_ON(offset < 0)) { + /* We see a crash here (when using BUG_ON) every few days under + * some torture tests. I'm not sure how to clean this up properly, + * so just return and hope thinks keep muddling through. --Ben + */ + printk("offset: %i start: %i seq: %i size: %i copy: %i\n", + offset, start, TCP_SKB_CB(skb)->seq, size, copy); + return; + } if (size > 0) { size = min(copy, size); if (skb_copy_bits(skb, offset, skb_put(nskb, size), size))
Thanks, Ben
-- Ben Greear <greearb@candelatech.com> Candela Technologies Inc http://www.candelatech.com
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