Subject: Re: [net] 2ab9fb18c4: kernel BUG at include/linux/skbuff.h:1935!

From: "Duyck, Alexander H" <[email-masked]>
Date: Mon, 14 Nov 2016 17:54:48 +0000

On Mon, 2016-11-14 at 07:49 +0800, kernel test robot wrote:
> FYI, we noticed the following commit:
> 
> https://github.com/0day-ci/linux Eric-Dumazet/net-__skb_flow_dissect-must-cap-its-return-value/20161110-080839
> commit 2ab9fb18c46b91b16a0f0f329336d3be9fc32deb ("net: __skb_flow_dissect() must cap its return value")
> 
> in testcase: kbuild
> with following parameters:
> 
> 	runtime: 300s
> 	nr_task: 50%
> 	cpufreq_governor: performance
> 
> 
> 
> 
> on test machine: 8 threads Intel(R) Atom(TM) CPU  C2750  @ 2.40GHz with 16G memory
> 
> caused below changes:
> 
> 
> +-------------------------------------------------------+------------+------------+
> > 
> >                                                       | cdb26d3387 | 2ab9fb18c4 |
> +-------------------------------------------------------+------------+------------+
> > 
> > boot_successes                                        | 10         | 3          |
> > boot_failures                                         | 0          | 9          |
> > kernel_BUG_at_include/linux/skbuff.h                  | 0          | 8          |
> > invalid_opcode:#[##]SMP                               | 0          | 8          |
> > RIP:eth_type_trans                                    | 0          | 8          |
> > Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0          | 5          |
> > WARNING:at_fs/sysfs/dir.c:#sysfs_warn_dup             | 0          | 1          |
> > calltrace:parport_pc_init                             | 0          | 1          |
> > calltrace:SyS_finit_module                            | 0          | 1          |
> > WARNING:at_lib/kobject.c:#kobject_add_internal        | 0          | 1          |
> +-------------------------------------------------------+------------+------------+
> 
> 
> 
> [   20.491020] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
> [   20.502988] Sending DHCP requests .
> [   20.506729] ------------[ cut here ]------------
> [   20.511369] kernel BUG at include/linux/skbuff.h:1935!
> [   20.517893] invalid opcode: 0000 [#1] SMP
> [   20.521902] Modules linked in:
> [   20.524979] CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.9.0-rc3-00286-g2ab9fb1 #1
> [   20.532463] Hardware name: Supermicro SYS-5018A-TN4/A1SAi, BIOS 1.1a 08/27/2015
> [   20.539768] task: ffff8804456c2480 task.stack: ffffc90001920000
> [   20.545684] RIP: 0010:[<ffffffff81837b48>]  [<ffffffff81837b48>] eth_type_trans+0xe8/0x140
> [   20.553972] RSP: 0018:ffff88047fd03db8  EFLAGS: 00010297
> [   20.559283] RAX: 0000000000000158 RBX: ffff88047d8ae600 RCX: 0000000000001073
> [   20.566415] RDX: ffff88047bf07dc0 RSI: ffff88047d8a4000 RDI: ffff88047dac0f00
> [   20.573546] RBP: ffff88047fd03e20 R08: ffff88047d8a4000 R09: 0000000000000800
> [   20.580678] R10: ffff88047bf07ec0 R11: ffffea0011f6e400 R12: ffff88047dac0f00
> [   20.587810] R13: ffff880457413000 R14: ffffc90002129000 R15: 000000000000015e
> [   20.594946] FS:  0000000000000000(0000) GS:ffff88047fd00000(0000) knlGS:0000000000000000
> [   20.603032] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   20.608775] CR2: 00007fffadfb4ef0 CR3: 000000047ee07000 CR4: 00000000001006e0
> [   20.615906] Stack:
> [   20.617927]  ffffffff816905a7 ffffea0011f6e400 ffffea0000000008 ffff88047d8ae450
> [   20.625403]  ffff88047d8ae400 0000004000000166 ffffea0011f6e400 0000ffff00000000
> [   20.632873]  0000000000000040 0000000000000000 ffff88047d8ae450 ffff88047d8b1140
> [   20.640352] Call Trace:
> [   20.642805]  <IRQ> 
> [   20.644740]  [<ffffffff816905a7>] ? igb_clean_rx_irq+0x6a7/0x7d0
> [   20.650760]  [<ffffffff81690a52>] igb_poll+0x382/0x700
> [   20.655904]  [<ffffffff8146edd9>] ? timerqueue_add+0x59/0xb0
> [   20.661564]  [<ffffffff8180f2d7>] net_rx_action+0x217/0x360
> [   20.667137]  [<ffffffff81957ef4>] __do_softirq+0x104/0x2ab
> [   20.672624]  [<ffffffff81086961>] irq_exit+0xf1/0x100
> [   20.677673]  [<ffffffff81957c34>] do_IRQ+0x54/0xd0
> [   20.682466]  [<ffffffff81955acc>] common_interrupt+0x8c/0x8c
> [   20.688123]  <EOI> 
> [   20.690054]  [<ffffffff817c1d12>] ? cpuidle_enter_state+0x122/0x2e0
> [   20.696333]  [<ffffffff817c1f07>] cpuidle_enter+0x17/0x20
> [   20.701733]  [<ffffffff810c64c3>] call_cpuidle+0x23/0x40
> [   20.707045]  [<ffffffff810c66f4>] cpu_startup_entry+0x114/0x200
> [   20.712964]  [<ffffffff81051c87>] start_secondary+0x107/0x130
> [   20.718708] Code: 00 04 00 00 c9 c3 48 33 86 70 03 00 00 48 c1 e0 10 48 85 c0 0f b6 87 90 00 00 00 75 28 83 e0 f8 83 c8 01 88 87 90 00 00 00 eb 82 <0f> 0b 0f b6 87 90 00 00 00 83 e0 f8 83 c8 03 88 87 90 00 00 00 
> [   20.738722] RIP  [<ffffffff81837b48>] eth_type_trans+0xe8/0x140
> [   20.744662]  RSP <ffff88047fd03db8>
> [   20.748160] ---[ end trace 153440bf1ca2e6fc ]---
> [   20.748165] ------------[ cut here ]------------
> 
> 
> To reproduce:
> 
>         git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
>         cd lkp-tests
>         bin/lkp install job.yaml  # job file is attached in this email
>         bin/lkp run     job.yaml
> 
> 
> 
> Thanks,
> Kernel Test Robot

So I am trying to reproduce this but need some additional data as just
copying the config apparently isn't enough.

I just wanted to confirm.  It looks like you are running serial over
lan over one of the igb ports.  Do I have that right?  I ask because
the igb driver loading in the dmesg log seems to cause a 2.1 second
skip and doesn't display the driver version or any information on the
igb devices.

Another question I had is what versions of gcc are you testing with?  I
see the dmesg for the failing case is using gcc version 6.2.  Are there
any other versions of gcc that are being tested, and if so are they
showing similar failures?

Thanks.

- Alex