Messages in this thread Patch in this message | | | From | Mathieu Malaterre <> | Subject | [PATCH] Revert "net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends" | Date | Fri, 15 Jun 2018 20:56:45 +0200 |
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This reverts commit 88078d98d1bb085d72af8437707279e203524fa5.
It causes regressions for people using chips driven by the sungem driver. Suspicion is that the skb->csum value isn't being adjusted properly.
Symptoms as seen on G4+sungem are:
[ 34.023281] eth0: hw csum failure [ 34.023438] CPU: 0 PID: 0 Comm: swapper Not tainted 4.17.0+ #2 [ 34.023618] Call Trace: [ 34.023707] [dffedbd0] [c069ddac] __skb_checksum_complete+0xf0/0x108 (unreliable) [ 34.023948] [dffedbf0] [c0777a70] tcp_v4_rcv+0x604/0xe00 [ 34.024118] [dffedc70] [c0731624] ip_local_deliver_finish+0xa8/0x3c4 [ 34.024315] [dffedcb0] [c0732430] ip_local_deliver+0xf0/0x154 [ 34.024493] [dffedcf0] [c07328dc] ip_rcv+0x448/0x774 [ 34.024653] [dffedd50] [c06aeae0] __netif_receive_skb_core+0x5e8/0x1184 [ 34.024857] [dffedde0] [c06bba20] napi_gro_receive+0x160/0x22c [ 34.025044] [dffede10] [e14b2590] gem_poll+0x7fc/0x1ac0 [sungem] [ 34.025228] [dffedee0] [c06bacf0] net_rx_action+0x34c/0x618 [ 34.025402] [dffedf60] [c07fd27c] __do_softirq+0x16c/0x5f0 [ 34.025575] [dffedfd0] [c0064c7c] irq_exit+0x110/0x1a8 [ 34.025738] [dffedff0] [c0016170] call_do_irq+0x24/0x3c [ 34.025903] [c0cf7e80] [c0009a84] do_IRQ+0x98/0x1a0 [ 34.026055] [c0cf7eb0] [c001b474] ret_from_except+0x0/0x14 [ 34.026225] --- interrupt: 501 at arch_cpu_idle+0x30/0x78 LR = arch_cpu_idle+0x30/0x78 [ 34.026510] [c0cf7f70] [c0cf6000] 0xc0cf6000 (unreliable) [ 34.026682] [c0cf7f80] [c00a3868] do_idle+0xc4/0x158 [ 34.026835] [c0cf7fb0] [c00a3ab0] cpu_startup_entry+0x20/0x28 [ 34.027013] [c0cf7fc0] [c0998820] start_kernel+0x47c/0x490 [ 34.027181] [c0cf7ff0] [00003444] 0x3444
See commit 7ce5a27f2ef8 ("Revert "net: Handle CHECKSUM_COMPLETE more adequately in pskb_trim_rcsum()."") for previous reference.
Link: https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-June/174444.html Reported-by: Meelis Roos <mroos@linux.ee> Fixes: 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends") Signed-off-by: Mathieu Malaterre <malat@debian.org> Cc: Eric Dumazet <edumazet@google.com> --- include/linux/skbuff.h | 5 +++-- net/core/skbuff.c | 14 -------------- 2 files changed, 3 insertions(+), 16 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index c86885954994..cbc753a3e41c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3134,7 +3134,6 @@ static inline void *skb_push_rcsum(struct sk_buff *skb, unsigned int len) return skb->data; } -int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len); /** * pskb_trim_rcsum - trim received skb and update checksum * @skb: buffer to trim @@ -3148,7 +3147,9 @@ static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) { if (likely(len >= skb->len)) return 0; - return pskb_trim_rcsum_slow(skb, len); + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->ip_summed = CHECKSUM_NONE; + return __pskb_trim(skb, len); } static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c642304f178c..360293d1baf3 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1840,20 +1840,6 @@ int ___pskb_trim(struct sk_buff *skb, unsigned int len) } EXPORT_SYMBOL(___pskb_trim); -/* Note : use pskb_trim_rcsum() instead of calling this directly - */ -int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len) -{ - if (skb->ip_summed == CHECKSUM_COMPLETE) { - int delta = skb->len - len; - - skb->csum = csum_sub(skb->csum, - skb_checksum(skb, len, delta, 0)); - } - return __pskb_trim(skb, len); -} -EXPORT_SYMBOL(pskb_trim_rcsum_slow); - /** * __pskb_pull_tail - advance tail of skb header * @skb: buffer to reallocate -- 2.11.0
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