From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [PATCH] ixgbe: drop zero length frame segments during a packet split rx Date: Tue, 13 Sep 2011 06:50:03 -0400 Message-ID: <20110913105003.GA16222@hmsreliant.think-freely.org> References: <1314972197-31557-1-git-send-email-nhorman@tuxdriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Thadeu Lima de Souza Cascardo , Jesse Brandeburg , Alexander Duyck , John Fastabend , Jeff Kirsher , "David S. Miller" To: netdev@vger.kernel.org Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:51828 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752356Ab1IMKuO (ORCPT ); Tue, 13 Sep 2011 06:50:14 -0400 Content-Disposition: inline In-Reply-To: <1314972197-31557-1-git-send-email-nhorman@tuxdriver.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Sep 02, 2011 at 10:03:17AM -0400, Neil Horman wrote: > This oops was reported recently no ppc64 hardware: > Unable to handle kernel paging request for data at address 0x00000000 > Faulting instruction address: 0xc0000000004dda0c > Oops: Kernel access of bad area, sig: 11 [#1] > SMP NR_CPUS=1024 NUMA pSeries > Modules linked in: sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 > iptable_fi > lter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state > nf_conntrack ip6table_filter ip6_tables ipv6 jsm ses enclosure sg ixgbe > mdio e1000 ehea ext4 jbd2 mbcache sd_mod crc_t10dif ipr dm_mod > NIP: c0000000004dda0c LR: c0000000004e3e50 CTR: c0000000004e3e20 > REGS: c0000001bffeb8d0 TRAP: 0300 Not tainted (3.1.0-rc2-10121-gab7e2db) > MSR: 8000000000009032 CR: 28002042 XER: 20000000 > CFAR: c000000000004d70 > DAR: 0000000000000000, DSISR: 40000000 > TASK = c000000000d548e0[0] 'swapper' THREAD: c000000000dfc000 CPU: 0 > GPR04: c0000000010f4d80 c0000001bffebd80 0000000000000000 c0000001b18a8200 > GPR08: 0000000000000280 c0000001bcc517a8 c0000001b18a7f80 0000000000000000 > GPR12: d0000000047e5bb0 c000000001f10000 c0000001b19c8700 0000000000000000 > GPR16: c0000001bffebd80 0000000000000083 c00000018f2447a0 0000000000000002 > GPR20: 0000000000000000 c0000001ba860010 c0000001ba860000 d000000003d40000 > GPR24: 0000000000000000 0000000000000083 d000000003d40000 0000000000000001 > GPR28: c00000018f244780 c0000001b2b94310 c000000000da95f0 c0000001bcc51780 > NIP [c0000000004dda0c] .skb_gro_reset_offset+0x5c/0xe0 > LR [c0000000004e3e50] .napi_gro_receive+0x30/0x120 > Call Trace: > [c0000001bffebb50] [c000000000da95f0] perf_callchain_user+0x0/0x10 (unreliable) > [c0000001bffebbf0] [d0000000047bd118] .ixgbe_clean_rx_irq+0x7a8/0x8a0 [ixgbe] > [c0000001bffebd10] [d0000000047bd414] .ixgbe_poll+0x64/0x160 [ixgbe] > [c0000001bffebdd0] [c0000000004e3358] .net_rx_action+0x108/0x2a0 > [c0000001bffebea0] [c00000000009b220] .__do_softirq+0x110/0x2a0 > [c0000001bffebf90] [c000000000023798] .call_do_softirq+0x14/0x24 > [c000000000dff830] [c000000000011148] .do_softirq+0xf8/0x130 > [c000000000dff8d0] [c00000000009aeb4] .irq_exit+0xb4/0xc0 > [c000000000dff950] [c000000000011254] .do_IRQ+0xd4/0x300 > [c000000000dffa10] [c000000000005024] hardware_interrupt_entry+0x18/0x74 > --- Exception: 501 at .pseries_dedicated_idle_sleep+0xe4/0x210 > LR = .pseries_dedicated_idle_sleep+0x8c/0x210 > [c000000000dffd00] [c00000000005b194] .pseries_dedicated_idle_sleep+0x194/0x210 > (unreliable) > [c000000000dffdc0] [c000000000018c84] .cpu_idle+0x164/0x210 > [c000000000dffe70] [c00000000000b0d0] .rest_init+0x90/0xb0 > [c000000000dffef0] [c000000000830bc0] .start_kernel+0x54c/0x56c > [c000000000dfff90] [c00000000000953c] .start_here_common+0x1c/0x60 > > Its caused when skb_gro_reset_offset attempts to call PageHighMem on > skb_shinfo(skb)->frags[0].page, when the frags array was left uninitalized. > This can happen in the ixgbe driver if the hardware reports a zero length rx > descriptor ni the middle of a packet split receive transaction. I've consulted > with Jesse Brandeburg on this, who is attempting to root cause the issue at > Intel, but it seems prudent to add this check to the driver to discard frames of > that encounter this error to avoid the opps > Sorry, I need to rescind this patch. Looks like this is turning out to be an issue with an ideosyncracy in the dma hardware on this platform. Thanks Neil