Messages in this thread Patch in this message |  | | Date | Tue, 28 Jan 2003 16:08:06 -0800 (PST) | Subject | Re: [TEST FIX] Re: SSH Hangs in 2.5.59 and 2.5.55 but not 2.4.x, | From | "David S. Miller" <> |
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From: kuznet@ms2.inr.ac.ru Date: Wed, 29 Jan 2003 02:56:41 +0300 (MSK)
Hey! Interesting thing has just happened, it is the first time when I found the bug formulating a senstence while writing e-mail not while peering to code. :-)
Congratulations :-)
Shheit, look into tcp_retrans_try_collapse():
if (skb->ip_summed != CHECKSUM_HW) { memcpy(skb_put(skb, next_skb_size), next_skb->data, nex$ skb->csum = csum_block_add(skb->csum, next_skb->csum, s$ } WHERE IS skb_put and copy when skb->ip_summed==CHECKSUM_HW??!! So, the fix is move of memcpy() line out of if clause. Indeed, this bug exists in 2.4 as well of course.
This bug is 2.4.3 vintage :-) It got added as part of initial zerocopy merge in fact.
Here is 2.4.x version of fix, 2.5.x is identicaly sans some line number differences. I will push this all to Linus/Marcelo.
BTW, Alexey, please please explain to me how that trick made by tcp_trim_head() works. :-) I am talking about how it is setting ip_summed to CHECKSUM_HARDWARE blindly and not even bothering to set skb->csum correctly.
--- net/ipv4/tcp_output.c.~1~ Tue Jan 28 16:12:39 2003 +++ net/ipv4/tcp_output.c Tue Jan 28 16:14:18 2003 @@ -721,10 +721,9 @@ if (next_skb->ip_summed == CHECKSUM_HW) skb->ip_summed = CHECKSUM_HW; - if (skb->ip_summed != CHECKSUM_HW) { - memcpy(skb_put(skb, next_skb_size), next_skb->data, next_skb_size); + memcpy(skb_put(skb, next_skb_size), next_skb->data, next_skb_size); + if (skb->ip_summed != CHECKSUM_HW) skb->csum = csum_block_add(skb->csum, next_skb->csum, skb_size); - } /* Update sequence range on original skb. */ TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(next_skb)->end_seq; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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