Re: 3.4.0-rc2: skb_put() -> skb_over_panic

[Eric Dumazet]

On Wed, 2012-04-18 at 00:15 +0400, Alexander Beregalov wrote:
> On 15 April 2012 19:16, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> > On Sun, 2012-04-15 at 16:24 +0400, Alexander Beregalov wrote:
> >> Hi
> >>
> >> kernel 3.4.0-rc2-00333-g668ce0a
> >>
> >> calltrace is lost on netconsole, sorry.
> >>
> >> ethernet is realtek/r8169
> >>
> >> It happened already two times with rtorrent, perhaps I can reproduce
> >> it, what else can I provide to you?
> >>
> > full stack trace needed please.
> >
> 
> This time calltrace is different (I saw few last lines of calltrace on
> a display, but not enough) and netconsole transmitted complete
> message, but perhaps it is the same problem. At least 'end' is the
> same.
> 
> 
> skb_over_panic: text:ffffffff8136d919 len:1248 put:932
> head:ffff8800babcf800 data:ffff8800babcfd10 tail:0x9f0 end:0x6c0
> dev:<NULL>
> ------------[ cut here ]------------
> kernel BUG at net/core/skbuff.c:127!
> invalid opcode: 0000 [#1] SMP
> CPU 3
> Modules linked in:
> 
> Pid: 1926, comm: rtorrent Not tainted 3.4.0-rc2-00333-g668ce0a #1
>             /D525MW
> RIP: 0010:[<ffffffff8132414a>]  [<ffffffff8132414a>] skb_put+0x7c/0x86
> RSP: 0018:ffff8800bed83d60  EFLAGS: 00010246
> RAX: 0000000000000098 RBX: ffff8800b0b244c0 RCX: 000000000000003d
> RDX: 000000000000000d RSI: 0000000000000046 RDI: ffffffff8162a0b0
> RBP: ffff8800bed83d80 R08: 0000000000000001 R09: 0000000000000000
> R10: ffff88002ed840c0 R11: 00000000007e28f6 R12: ffff8800b9cb9180
> R13: ffff8800b9cb96c0 R14: ffff8800b9cb91a8 R15: ffff8800b0b245a0
> FS:  00007fe639e75720(0000) GS:ffff8800bed80000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fe63571a000 CR3: 00000000b53fa000 CR4: 00000000000007e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process rtorrent (pid: 1926, threadinfo ffff8800bb0a0000, task ffff8800bb1dddc0)
> Stack:
>  00000000000009f0 00000000000006c0 ffffffff814d06e7 ffff8800b9cb9180
>  ffff8800bed83de0 ffffffff8136d919 ffff8800000003a4 0000013c81536640
>  ffff8800b0b245a0 000000cc00000006 ffff8800b0b244c0 ffff8800b0b244c0
> Call Trace:
>  <IRQ>
>  [<ffffffff8136d919>] tcp_retransmit_skb+0x29a/0x529
>  [<ffffffff8136eebd>] tcp_retransmit_timer+0x358/0x4e7
>  [<ffffffff8136f0e8>] tcp_write_timer+0x9c/0x17d
>  [<ffffffff81035bd0>] run_timer_softirq+0x1eb/0x2bf
>  [<ffffffff8136f04c>] ? tcp_retransmit_timer+0x4e7/0x4e7
>  [<ffffffff810184e9>] ? native_smp_send_reschedule+0x4f/0x51
>  [<ffffffff8102fb52>] __do_softirq+0xbf/0x17d
>  [<ffffffff810188ec>] ? lapic_next_event+0x18/0x1c
>  [<ffffffff813c05cc>] call_softirq+0x1c/0x30
>  [<ffffffff810033d6>] do_softirq+0x33/0x69
>  [<ffffffff8102fdc6>] irq_exit+0x44/0x9c
>  [<ffffffff81018c6f>] smp_apic_timer_interrupt+0x86/0x94
>  [<ffffffff813bfe47>] apic_timer_interrupt+0x67/0x70
>  <EOI>
>  [<ffffffff8131d87e>] ? sock_sendmsg+0xe6/0x106
>  [<ffffffff8135fb7b>] ? tcp_poll+0xaf/0x168
>  [<ffffffff810ff814>] ? ep_send_events_proc+0x67/0x116
>  [<ffffffff8131b8ef>] sock_poll+0x15/0x17
>  [<ffffffff810ff823>] ep_send_events_proc+0x76/0x116
>  [<ffffffff810ff7ad>] ? ep_read_events_proc+0x99/0x99
>  [<ffffffff810fff24>] ep_scan_ready_list.clone.6+0x8f/0x16f
>  [<ffffffff81100277>] ep_poll+0x25f/0x2e2
>  [<ffffffff8131e886>] ? sys_accept4+0x133/0x15f
>  [<ffffffff81100d8e>] sys_epoll_wait+0x90/0xae
>  [<ffffffff813bf2e6>] system_call_fastpath+0x1a/0x1f
> Code: 8b 57 60 48 89 44 24 10 8b 87 ac 00 00 00 48 89 44 24 08 31 c0
> 8b bf a8 00 00 00 48 89 3c 24 48 c7 c7 43 07 4d 81 e8 2c 27 09 00 <0f>
> 0b 89 c0 49 8d 04 00 c9 c3 55 48 89 e5 41 57 41 56 41 55 41
> RIP  [<ffffffff8132414a>] skb_put+0x7c/0x86
>  RSP <ffff8800bed83d60>
> ---[ end trace a721715cd86be064 ]---

Thanks a lot, I belive I know where the problem is.

Could you check if commit a21d45726acacc963d8baddf74607d9b74e2b723
(tcp: avoid order-1 allocations on wifi and tx path)
was in your tree ?



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