Oops after cd /sys/.../cpufreq/; rmmod; cat stats/time_in_state

Alexey Dobriyan
2007-03-19T15:22:35Z

Steps to reproduce:

# modprobe p4-clockmod
$ cd /sys/devices/system/cpu/cpu0/cpufreq/
# rmmod p4-clockmod
$ cat stats/time_in_state
Segmentation fault

p4-clockmod: P4/Xeon(TM) CPU On-Demand Clock Modulation available
BUG: unable to handle kernel paging request at virtual address 6b6b6b6f
printing eip:
c01906b4
*pde = 00000000
Oops: 0000 [#1]
PREEMPT
Modules linked in: speedstep_lib ohci_hcd af_packet e1000 ehci_hcd uhci_hcd usbcore xfs
CPU: 0
EIP: 0060:[<c01906b4>] Not tainted VLI
EFLAGS: 00010202 (2.6.21-rc4-5851fadce8824d5d4b8fd02c22ae098401f6489e #2)
EIP is at sysfs_open_file+0xd3/0x259
eax: 6b6b6b6b ebx: 00000000 ecx: f371b000 edx: 00000000
esi: c03a7330 edi: f35c8408 ebp: f371c9b0 esp: f371bee0
ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068
Process cat (pid: 6876, ti=f371b000 task=c192f550 task.ti=f371b000)
Stack: f3713b2c c0393400 00000000 f371c9b0 00000000 f3713b2c c01905e1 c0158575
c18d3208 f71c4cd8 00000000 f371c9b0 00008000 f371bf38 ffffff9c c0158702
f371c9b0 00000000 00000000 c0158744 00000000 f371bf38 f71c4cd8 c18d3208
Call Trace:
[<c01905e1>] sysfs_open_file+0x0/0x259
[<c0158575>] __dentry_open+0xec/0x1ec
[<c0158702>] nameidata_to_filp+0x31/0x3a
[<c0158744>] do_filp_open+0x39/0x40
[<c0158478>] get_unused_fd+0xa1/0xb2
[<c02d4cde>] _spin_unlock+0x25/0x3b
[<c0158478>] get_unused_fd+0xa1/0xb2
[<c0158785>] do_sys_open+0x3a/0x6d
[<c01587f3>] sys_open+0x1c/0x20
[<c0103e72>] sysenter_past_esp+0x5f/0x99
=======================
Code: 00 f0 ff ff 8b 40 08 a8 08 0f 85 95 01 00 00 bb ed ff ff ff 8b 44 24 08 85 c0 0f 84 f8 00 00 00 8b 47 28 85 c0 0f 84 34 01 00 00 <8b> 40 04 85 c0 0f 84 29 01 00 00 8b 58 04 85 db 0f 84 0f 01 00
EIP: [<c01906b4>] sysfs_open_file+0xd3/0x259 SS:ESP 0068:f371bee0
Slab corruption: start=f35c83bc, len=256
Redzone: 0x5a2cf071/0x5a2cf071.
Last user: [<c0181d54>](load_elf_binary+0x161b/0x1ac7)
060: 6b 6b 6b 6b 6c 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Prev obj: start=f35c82b0, len=256
Redzone: 0x170fc2a5/0x170fc2a5.
Last user: [<c0180758>](load_elf_binary+0x1f/0x1ac7)
000: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
010: 02 00 03 00 01 00 00 00 b0 85 04 08 34 00 00 00
Next obj: start=f35c84c8, len=256
Redzone: 0x170fc2a5/0x170fc2a5.
Last user: [<c01807ea>](load_elf_binary+0xb1/0x1ac7)
000: 06 00 00 00 34 00 00 00 34 80 04 08 34 80 04 08
010: 00 01 00 00 00 01 00 00 05 00 00 00 04 00 00 00