Re: kernel BUG at kernel/timer.c:748!

From: Jerry Chu <hkchu@google.com>
To: Lin Ming <mlin@ss.pku.edu.cn>
Cc: Dave Jones <davej@redhat.com>, netdev@vger.kernel.org
Subject: Re: kernel BUG at kernel/timer.c:748!
Date: Wed, 5 Sep 2012 14:18:00 -0700	[thread overview]
Message-ID: <CAPshTChw_djp6xeZf-A5WpSsdpRAm4YP8mf3ZP+W76YtRSjfrw@mail.gmail.com> (raw)
In-Reply-To: <CAF1ivSauxzNhrm9c==_xFpuh9Lo3KrUNLNRb_62fLZxMfTuU1w@mail.gmail.com>

On Wed, Sep 5, 2012 at 9:04 AM, Lin Ming <mlin@ss.pku.edu.cn> wrote:
> On Wed, Sep 5, 2012 at 12:35 PM, Dave Jones <davej@redhat.com> wrote:
>> Just hit this bug on 3.6-rc4.
>>
>> The BUG is..
>>
>>         BUG_ON(!timer->function);
>
> TCP keepalive timer is setup when the socket is created.
>
> __sock_create
> inet_create
> tcp_v4_init_sock
> tcp_init_sock
> tcp_init_xmit_timers
> inet_csk_init_xmit_timers
>
> timer->function should not be NULL when set keepalive option.

And tcp_init_xmit_timers() is called on the passive open side as well, v4
as well as v6. I don't see any code explicitly set timer->function back to NULL
(unless through set_timer(..., NULL,...). This may be a corrupted sock (already
released?)

Jerry

>
> Strange...have bug somewhere.
>
> Lin Ming
>
>>
>>
>> Not much to go on... Any thoughts on what I could add to get
>> more debug info on which protocol etc this was ?
>>
>>         Dave
>>
>>
>> kernel BUG at kernel/timer.c:748!
>> invalid opcode: 0000 [#1] SMP
>> Modules linked in: tun fuse ipt_ULOG binfmt_misc nfnetlink nfc caif_socket caif phonet can llc2 pppoe pppox ppp_generic slhc irda crc_ccitt rds af_key decnet rose x25 atm netrom appletalk ipx p8023 psnap p8022 llc ax25 nfsv3 nfs_acl nfs fscache lockd sunrpc bluetooth rfkill ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode pcspkr i2c_i801 e1000e uinput i915 video i2c_algo_bit drm_kms_helper drm i2c_core
>> CPU 3
>> Pid: 12330, comm: trinity-child3 Not tainted 3.6.0-rc4+ #36
>> RIP: 0010:[<ffffffff810813f5>]  [<ffffffff810813f5>] mod_timer+0x2c5/0x2f0
>> RSP: 0018:ffff88000dfd7e08  EFLAGS: 00010246
>> RAX: 000000000000001a RBX: ffff880122d62948 RCX: 000000000000001a
>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88000dfd7e10
>> RBP: ffff88000dfd7e48 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000001517000 R11: 0000000000000246 R12: 000000016c000000
>> R13: 000000016c12bcb1 R14: ffff8801236cee00 R15: 00000000ffffff01
>> FS:  00007fa96745f740(0000) GS:ffff880148200000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00000000100ff000 CR3: 0000000099344000 CR4: 00000000001407e0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>> Process trinity-child3 (pid: 12330, threadinfo ffff88000dfd6000, task ffff880090890000)
>> Stack:
>>  ffffffff8154cb6d 0000000007b5edf7 ffff88000dfd7e28 ffff880122d62520
>>  0000000000000009 0000000000000004 ffff8801236cee00 00000000ffffff01
>>  ffff88000dfd7e68 ffffffff8154c79c ffffffff81550e6c ffff880122d62520
>> Call Trace:
>>  [<ffffffff8154cb6d>] ? lock_sock_nested+0x8d/0xa0
>>  [<ffffffff8154c79c>] sk_reset_timer+0x1c/0x30
>>  [<ffffffff81550e6c>] ? sock_setsockopt+0x8c/0x960
>>  [<ffffffff815a84a0>] inet_csk_reset_keepalive_timer+0x20/0x30
>>  [<ffffffff815c018d>] tcp_set_keepalive+0x3d/0x50
>>  [<ffffffff81551703>] sock_setsockopt+0x923/0x960
>>  [<ffffffff810ddf76>] ? trace_hardirqs_on_caller+0x16/0x1e0
>>  [<ffffffff811db0ac>] ? fget_light+0x24c/0x520
>>  [<ffffffff8154af86>] sys_setsockopt+0xc6/0xe0
>>  [<ffffffff816a50ed>] system_call_fastpath+0x1a/0x1f
>> Code: 00 74 43 9c 58 0f 1f 44 00 00 f6 c4 02 0f 84 14 ff ff ff eb 93 48 c7 c7 20 48 c3 81 e8 f5 70 05 00 85 c0 0f 85 fe fe ff ff eb b7 <0f> 0b 48 8b 75 08 48 89 df e8 3d f6 ff ff e9 b2 fd ff ff 4d 89
>> RIP  [<ffffffff810813f5>] mod_timer+0x2c5/0x2f0
>>  RSP <ffff88000dfd7e08>
>> ---[ end trace 7e7b5910138e49a3 ]---
>>
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