Kernel BUG at NULL Pointer Dereference

[Ins <insfocus at gmail dot com>]

Hi all,

   I compiled the latest kernel from Linus's git, and the latest systemtap.

> home/rock/systemtap-2.1-7162/bin/stap -ve 'probe module("btrfs").function("*"){printf("%s\n", probefunc());}'

After ran this, I got the NULL Pointer dereference, the detailed log I
paste below.  And every time I got one kernel thread doesn't exit
normally.

[stapio] <defunct>

So did somebody have met this problem before?


Dmesg Log:

[22816.202933] BUG: unable to handle kernel NULL pointer dereference
at 00000000000000ca
[22816.203027] IP: [<ffffffff812e90b8>] strcmp+0x8/0x30
[22816.203080] PGD 10bf57067 PUD 11204b067 PMD 0
[22816.203130] Oops: 0000 [#1] SMP
[22816.203166] Modules linked in:
stap_8eed450ffabfaa1bce874c07b2dd847e_14_9337(O) btrfs zlib_deflate
libcrc32c tcp_lp hidp fuse lockd sunrpc rfcomm bnep ip6t_REJECT
nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables
nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack arc4 iwldvm
mac80211 snd_hda_codec_hdmi btusb bluetooth snd_hda_codec_realtek
coretemp kvm_intel kvm snd_hda_intel snd_hda_codec snd_hwdep iwlwifi
snd_seq snd_seq_device snd_pcm cfg80211 snd_page_alloc thinkpad_acpi
e1000e snd_timer snd iTCO_wdt rfkill tpm_tis i2c_i801
iTCO_vendor_support lpc_ich wmi soundcore tpm tpm_bios mei mfd_core
joydev microcode pcspkr uinput dm_crypt crc32c_intel
ghash_clmulni_intel sdhci_pci sdhci mmc_core i915 video i2c_algo_bit
drm_kms_helper drm i2c_core [last unloaded: zlib_deflate]
[22816.203982] CPU 2
[22816.204006] Pid: 9337, comm: stapio Tainted: G           O
3.7.0-rc6+ #1 LENOVO 2356BG6/2356BG6
[22816.204082] RIP: 0010:[<ffffffff812e90b8>]  [<ffffffff812e90b8>]
strcmp+0x8/0x30
[22816.204151] RSP: 0018:ffff88013297be68  EFLAGS: 00010206
[22816.204197] RAX: ffff88013801aa80 RBX: 000000000000000c RCX: 0000000000000000
[22816.204257] RDX: 0000000000000000 RSI: ffffffffa068a728 RDI: 00000000000000ca
[22816.204318] RBP: ffff88013297be68 R08: ffff8800532c3a30 R09: 00007fb03ce06700
[22816.204378] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000000ca
[22816.204438] R13: 0000000000000000 R14: 0000000000000008 R15: 0000000000000000
[22816.204499] FS:  00007fb043a35740(0000) GS:ffff88013e280000(0000)
knlGS:0000000000000000
[22816.204567] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[22816.204616] CR2: 00000000000000ca CR3: 000000010bf1a000 CR4: 00000000001407e0
[22816.204676] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[22816.204736] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[22816.204797] Process stapio (pid: 9337, threadinfo ffff88013297a000,
task ffff880137bf2e40)
[22816.204866] Stack:
[22816.204885]  ffff88013297bef8 ffffffffa067f53a 00007fffffffeffd
0000000000000002
[22816.204959]  ffff8800532c3a00 0000000000000002 ffff88013297bec8
ffffffff81284bcc
[22816.205032]  ffffffff8105d562 000000000000000c ffff8800532c3a00
0000000000000000
[22816.205105] Call Trace:
[22816.205138]  [<ffffffffa067f53a>] _stp_ctl_write_cmd+0x32a/0x1250
[stap_8eed450ffabfaa1bce874c07b2dd847e_14_9337]
[22816.205227]  [<ffffffff81284bcc>] ? security_file_permission+0x2c/0xb0
[22816.205287]  [<ffffffff8105d562>] ? do_fork+0x142/0x3a0
[22816.205334]  [<ffffffff8119174c>] vfs_write+0xac/0x180
[22816.205381]  [<ffffffff81191a92>] sys_write+0x52/0xa0
[22816.208187]  [<ffffffff8101d348>] ? sys_clone+0x28/0x30
[22816.211013]  [<ffffffff81635663>] ? stub_clone+0x13/0x20
[22816.213860]  [<ffffffff81635359>] system_call_fastpath+0x16/0x1b

--
Thanks.
-Rock