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Date: Sat, 04 Apr 2009 10:34:39 -0400
From: Masami Hiramatsu <mhiramat@redhat.com>
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To: Ingo Molnar <mingo@elte.hu>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: LKML <linux-kernel@vger.kernel.org>,
       systemtap-ml <systemtap@sources.redhat.com>
Subject: [BUG][-tip] kprobes on module functions hits kernel BUG in text_poke
 on x86-32
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Hi,

I found text_poke() problem on x86-32 with the latest-tip tree.
When I put a kprobe on a module function, text_poke() hit a BUG.

This bug can be reproduced on x86-32, but not on x86-64.
And inserting kprobes on a kernel-core function is OK.

Thank you,

------------[ cut here ]------------
kernel BUG at /home/mhiramat/ksrc/linux-2.6-tip/arch/x86/kernel/alternative.c:543!
invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
last sysfs file: /sys/devices/pci0000:00/0000:00:03.0/0000:02:00.0/net/eth0/broadcast
Modules linked in: probe_bench(+) netconsole configfs sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_state
nf_conntrack iptable_filter ip_tables ip6table_filter ip6_tables ipv6 cpufreq_ondemand powernow_k8 dm_mirror
dm_region_hash dm_log dm_multipath uinput snd_hda_codec_idt snd_hda_intel snd_hda_codec snd_hwdep snd_seq_dummy
snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd soundcore dcdbas
i2c_nforce2 pcspkr tg3 snd_page_alloc rtc_cmos rtc_core i2c_core libphy rtc_lib ata_generic pata_acpi sata_nv [last
unloaded: scsi_wait_scan]

Pid: 5411, comm: insmod Not tainted (2.6.29-tip #8) OptiPlex 740
EIP: 0060:[<c06e97ef>] EFLAGS: 00210893 CPU: 0
EIP is at text_poke+0x168/0x1a4
EAX: 00040f55 EBX: 00020800 ECX: f45d8f03 EDX: 00000000
ESI: f45d8f04 EDI: ffc58001 EBP: f45d8ef8 ESP: f45d8ed8
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process insmod (pid: 5411, ti=f45d8000 task=f4490000 task.ti=f45d8000)
Stack:
 00000001 f45d8f03 f8464000 00200286 00000000 00000000 00000000 f846492c
 f45d8f04 c06ea30d cc46492c f45d8f30 c06eb4bb 000000d8 f8464934 f84647e4
 f84647e4 00936fc0 f45d8f30 f84647e4 fffffffc 00936fc0 f45d8f40 f8464110
Call Trace:
 [<f8464000>] ? dummy_function+0x0/0xb [probe_bench]
 [<c06ea30d>] ? arch_arm_kprobe+0x1a/0x1c
 [<c06eb4bb>] ? register_kprobe+0x3b8/0x40a
 [<f8464110>] ? install_probe+0x31/0x13d [probe_bench]
 [<c040304f>] ? do_one_initcall+0x4a/0x11a
 [<f84640df>] ? install_probe+0x0/0x13d [probe_bench]
 [<c044b8fe>] ? up_read+0x16/0x2c
 [<c044c14e>] ? __blocking_notifier_call_chain+0x40/0x4c
 [<c045e5e4>] ? sys_init_module+0x89/0x18c
 [<c0407b44>] ? sysenter_do_call+0x12/0x38
Code: 00 00 6a 00 ff 15 04 83 85 c0 58 5a e8 86 82 d3 ff 90 b8 01 00 00 00 0f a2 31 d2 eb 13 8b 4d e8 8a 04 11 8b 4d e4
3a 04 11 74 04 <0f> 0b eb fe 42 3b 55 e0 72 e8 f7 45 ec 00 02 00 00 75 10 8b 45
EIP: [<c06e97ef>] text_poke+0x168/0x1a4 SS:ESP 0068:f45d8ed8
---[ end trace 12f1ca8c7f7964a0 ]---
Kernel panic - not syncing: Fatal exception
Pid: 5411, comm: insmod Tainted: G      D    2.6.29-tip #8
Call Trace:
 [<c06e6081>] ? printk+0xf/0x16
 [<c06e5fc8>] panic+0x39/0xe3
 [<c06e9526>] oops_end+0x96/0xa5
 [<c040a486>] die+0x54/0x5a
 [<c06e8e43>] do_trap+0x89/0xa2
 [<c0408bbe>] ? do_invalid_op+0x0/0x7b
 [<c0408c2f>] do_invalid_op+0x71/0x7b
 [<c06e97ef>] ? text_poke+0x168/0x1a4
 [<c045567d>] ? mark_lock+0x1e/0x1e0
 [<c042672c>] ? set_pte_vaddr+0xac/0xcf
 [<c054d6fc>] ? trace_hardirqs_off_thunk+0xc/0x10
 [<c06e8bfa>] error_code+0x72/0x78
 [<c0408bbe>] ? do_invalid_op+0x0/0x7b
 [<c06e97ef>] ? text_poke+0x168/0x1a4
 [<f8464000>] ? dummy_function+0x0/0xb [probe_bench]
 [<c06ea30d>] arch_arm_kprobe+0x1a/0x1c
 [<c06eb4bb>] register_kprobe+0x3b8/0x40a
 [<f8464110>] install_probe+0x31/0x13d [probe_bench]
 [<c040304f>] do_one_initcall+0x4a/0x11a
 [<f84640df>] ? install_probe+0x0/0x13d [probe_bench]
 [<c044b8fe>] ? up_read+0x16/0x2c
 [<c044c14e>] ? __blocking_notifier_call_chain+0x40/0x4c
 [<c045e5e4>] sys_init_module+0x89/0x18c
 [<c0407b44>] sysenter_do_call+0x12/0x38
Rebooting in 5 seconds..

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com