Hi,
I have just compiled Linux 2.2.18 (UP) and Linux 2.4.0-test12 (SMP,
devfs), and in each case I compiled the msr and cpuid drivers as
modules. However, when I tried to read from the devices (using "cat"),
I got oopses from both 2.2.18 and 2.4.0-test12. Neither the msr.o nor
the cpuid.o modules were loaded beforehand, as I was testing my kmod
setup. The oopses are below:
Linux-2.4.0-test12 (2 oopses):
$ ksymoops -m /boot/System.map-2.4.0-test12 < oops1.txt
ksymoops 2.3.4 on i686 2.4.0-test12. Options used
-V (default)
-k /proc/ksyms (default)
-l /proc/modules (default)
-o /lib/modules/2.4.0-test12/ (default)
-m /boot/System.map-2.4.0-test12 (specified)
Dec 13 01:17:47 twopit kernel: Unable to handle kernel paging request at virtual address d084a540
Dec 13 01:17:47 twopit kernel: c0133d8a
Dec 13 01:17:47 twopit kernel: *pde = 0146b063
Dec 13 01:17:47 twopit kernel: Oops: 0000
Dec 13 01:17:47 twopit kernel: CPU: 1
Dec 13 01:17:47 twopit kernel: EIP: 0010:[get_chrfops+78/368]
Dec 13 01:17:47 twopit kernel: EFLAGS: 00010282
Dec 13 01:17:47 twopit kernel: eax: 00000650 ebx: d084a540 ecx: c0215280 edx: c0268de4
Dec 13 01:17:47 twopit kernel: esi: 00000000 edi: 00000650 ebp: 000000ca esp: cb505ee8
Dec 13 01:17:47 twopit kernel: ds: 0018 es: 0018 ss: 0018
Dec 13 01:17:47 twopit kernel: Process cat (pid: 1681, stackpage=cb505000)
Dec 13 01:17:47 twopit kernel: Stack: cf41e140 cccfef60 ffffffed cb998580 c0215280 c02158b8 cbcd7840 00000000
Dec 13 01:17:47 twopit kernel: c013ed99 c999ca60 c013403a 000000ca 00000001 cf41e140 ffffffed cf41e144
Dec 13 01:17:47 twopit kernel: cb998580 c015b5d1 cb998580 cccfef60 cccfef60 cb998580 ffffffe9 c14fa240
Dec 13 01:17:47 twopit kernel: Call Trace: [path_walk+1997/2196] [chrdev_open+38/172] [devfs_open+277/500] [dentry_open+189/332] [filp_open+82/92] [sys_open+60/240] [system_call+51/56]
Dec 13 01:17:47 twopit kernel: Code: 8b 03 85 c0 74 10 50 e8 62 8b fe ff 83 c4 04 85 c0 74 09 8d
Using defaults from ksymoops -t elf32-i386 -a i386
Code; 00000000 Before first symbol
00000000 <_EIP>:
Code; 00000000 Before first symbol
0: 8b 03 mov (%ebx),%eax
Code; 00000002 Before first symbol
2: 85 c0 test %eax,%eax
Code; 00000004 Before first symbol
4: 74 10 je 16 <_EIP+0x16> 00000016 Before first symbol
Code; 00000006 Before first symbol
6: 50 push %eax
Code; 00000007 Before first symbol
7: e8 62 8b fe ff call fffe8b6e <_EIP+0xfffe8b6e> fffe8b6e <END_OF_CODE+2f726606/????>
Code; 0000000c Before first symbol
c: 83 c4 04 add $0x4,%esp
Code; 0000000f Before first symbol
f: 85 c0 test %eax,%eax
Code; 00000011 Before first symbol
11: 74 09 je 1c <_EIP+0x1c> 0000001c Before first symbol
Code; 00000013 Before first symbol
13: 8d 00 lea (%eax),%eax
$ ksymoops -m /boot/System.map-2.4.0-test12 < oops2.txt
ksymoops 2.3.4 on i686 2.4.0-test12. Options used
-V (default)
-k /proc/ksyms (default)
-l /proc/modules (default)
-o /lib/modules/2.4.0-test12/ (default)
-m /boot/System.map-2.4.0-test12 (specified)
Dec 13 01:20:02 twopit kernel: Unable to handle kernel paging request at virtual address d084a540
Dec 13 01:20:02 twopit kernel: c0133d8a
Dec 13 01:20:02 twopit kernel: *pde = 0146b063
Dec 13 01:20:02 twopit kernel: Oops: 0000
Dec 13 01:20:02 twopit kernel: CPU: 0
Dec 13 01:20:02 twopit kernel: EIP: 0010:[get_chrfops+78/368]
Dec 13 01:20:02 twopit kernel: EFLAGS: 00010282
Dec 13 01:20:02 twopit kernel: eax: 00000650 ebx: d084a540 ecx: c0215280 edx: c0268de4
Dec 13 01:20:02 twopit kernel: esi: 00000000 edi: 00000650 ebp: 000000ca esp: cb52bee8
Dec 13 01:20:02 twopit kernel: ds: 0018 es: 0018 ss: 0018
Dec 13 01:20:02 twopit kernel: Process cat (pid: 1691, stackpage=cb52b000)
Dec 13 01:20:02 twopit kernel: Stack: cf41e140 cc605bc0 ffffffed cb998580 c0215280 c02158b8 cbcd7840 00000000
Dec 13 01:20:02 twopit kernel: c013ed99 c999ca60 c013403a 000000ca 00000001 cf41e140 ffffffed cf41e144
Dec 13 01:20:02 twopit kernel: cb998580 c015b5d1 cb998580 cc605bc0 cc605bc0 cb998580 ffffffe9 c14fa240
Dec 13 01:20:02 twopit kernel: Call Trace: [path_walk+1997/2196] [chrdev_open+38/172] [devfs_open+277/500] [dentry_open+189/332] [filp_open+82/92] [sys_open+60/240] [system_call+51/56]
Dec 13 01:20:02 twopit kernel: Code: 8b 03 85 c0 74 10 50 e8 62 8b fe ff 83 c4 04 85 c0 74 09 8d
Using defaults from ksymoops -t elf32-i386 -a i386
Code; 00000000 Before first symbol
00000000 <_EIP>:
Code; 00000000 Before first symbol
0: 8b 03 mov (%ebx),%eax
Code; 00000002 Before first symbol
2: 85 c0 test %eax,%eax
Code; 00000004 Before first symbol
4: 74 10 je 16 <_EIP+0x16> 00000016 Before first symbol
Code; 00000006 Before first symbol
6: 50 push %eax
Code; 00000007 Before first symbol
7: e8 62 8b fe ff call fffe8b6e <_EIP+0xfffe8b6e> fffe8b6e <END_OF_CODE+2f726606/????>
Code; 0000000c Before first symbol
c: 83 c4 04 add $0x4,%esp
Code; 0000000f Before first symbol
f: 85 c0 test %eax,%eax
Code; 00000011 Before first symbol
11: 74 09 je 1c <_EIP+0x1c> 0000001c Before first symbol
Code; 00000013 Before first symbol
13: 8d 00 lea (%eax),%eax
Linux-2.2.18 (1 oops):
$ ksymoops -m /boot/System.map-2.2.18 < oops.txt
ksymoops 2.3.4 on i586 2.2.18. Options used
-V (default)
-k /proc/ksyms (default)
-l /proc/modules (default)
-o /lib/modules/2.2.18/ (default)
-m /boot/System.map-2.2.18 (specified)
Warning (compare_maps): ksyms_base symbol module_list_R__ver_module_list not found in System.map. Ignoring ksyms_base entry
Dec 13 01:31:18 wellhouse kernel: Unable to handle kernel paging request at virtual address c887027c
Dec 13 01:31:18 wellhouse kernel: current->tss.cr3 = 007ad000, %%cr3 = 007ad000
Dec 13 01:31:18 wellhouse kernel: *pde = 01472063
Dec 13 01:31:18 wellhouse kernel: Oops: 0000
Dec 13 01:31:18 wellhouse kernel: CPU: 0
Dec 13 01:31:18 wellhouse kernel: EIP: 0010:[chrdev_open+56/88]
Dec 13 01:31:18 wellhouse kernel: EFLAGS: 00010286
Dec 13 01:31:18 wellhouse kernel: eax: c8870260 ebx: ffffffed ecx: 00000000 edx: 000000cb
Dec 13 01:31:18 wellhouse kernel: esi: c34d4380 edi: c0565e60 ebp: c3c35900 esp: c3b47f4c
Dec 13 01:31:18 wellhouse kernel: ds: 0018 es: 0018 ss: 0018
Dec 13 01:31:18 wellhouse kernel: Process cat (pid: 1645, process nr: 53, stackpage=c3b47000)
Dec 13 01:31:18 wellhouse kernel: Stack: c0565e60 00008000 00000003 400e88b3 bffffa4c c012497c c0565e60 c34d4380
Dec 13 01:31:18 wellhouse kernel: 00000000 c01248d5 00000003 c05a3000 400e88b3 bffffa4c 00000000 c398549c
Dec 13 01:31:18 wellhouse kernel: 00000400 c0124b6f c05a3000 00008000 00000000 c0124b56 c3b46000 40013ed0
Dec 13 01:31:18 wellhouse kernel: Call Trace: [filp_open+184/264] [filp_open+17/264] [sys_open+63/160] [sys_open+38/160] [error_code+45/64] [
system_call+52/64]
Dec 13 01:31:18 wellhouse kernel: Code: 8b 40 1c 31 db 85 c0 74 0c 83 c4 f8 56 57 ff d0 89 c3 83 c4
Using defaults from ksymoops -t elf32-i386 -a i386
Code; 00000000 Before first symbol
00000000 <_EIP>:
Code; 00000000 Before first symbol
0: 8b 40 1c mov 0x1c(%eax),%eax
Code; 00000003 Before first symbol
3: 31 db xor %ebx,%ebx
Code; 00000005 Before first symbol
5: 85 c0 test %eax,%eax
Code; 00000007 Before first symbol
7: 74 0c je 15 <_EIP+0x15> 00000015 Before first symbol
Code; 00000009 Before first symbol
9: 83 c4 f8 add $0xfffffff8,%esp
Code; 0000000c Before first symbol
c: 56 push %esi
Code; 0000000d Before first symbol
d: 57 push %edi
Code; 0000000e Before first symbol
e: ff d0 call *%eax
Code; 00000010 Before first symbol
10: 89 c3 mov %eax,%ebx
Code; 00000012 Before first symbol
12: 83 c4 00 add $0x0,%esp
1 warning issued. Results may not be reliable.
I know they're not exactly show-stoppers, but here they are anyway.
Cheers,
Chris
Devfs might explain the 2.4.0-test12 oopses, but it can't possibly
explain the oops with 2.2.18. I don't use devfs with 2.2.18.
Chris
> Looks like a devfs problem; complain to the appropriate people. I refuse
> to touch that particular devfs code.
>
> > I have just compiled Linux 2.2.18 (UP) and Linux 2.4.0-test12 (SMP,
> > devfs), and in each case I compiled the msr and cpuid drivers as
> > modules. However, when I tried to read from the devices (using "cat"),
> > I got oopses from both 2.2.18 and 2.4.0-test12. Neither the msr.o nor
> > the cpuid.o modules were loaded beforehand, as I was testing my kmod
> > setup. The oopses are below:
[2.4.0-test12 oopses removed]
> > Linux-2.2.18 (1 oops):
> > $ ksymoops -m /boot/System.map-2.2.18 < oops.txt
> > ksymoops 2.3.4 on i586 2.2.18. Options used
> > -V (default)
> > -k /proc/ksyms (default)
> > -l /proc/modules (default)
> > -o /lib/modules/2.2.18/ (default)
> > -m /boot/System.map-2.2.18 (specified)
> >
> > Warning (compare_maps): ksyms_base symbol module_list_R__ver_module_list
> not found in System.map. Ignoring ksyms_base entry
> > Dec 13 01:31:18 wellhouse kernel: Unable to handle kernel paging request
> at virtual address c887027c
> > Dec 13 01:31:18 wellhouse kernel: current->tss.cr3 = 007ad000, %%cr3 =
> 007ad000
> > Dec 13 01:31:18 wellhouse kernel: *pde = 01472063
> > Dec 13 01:31:18 wellhouse kernel: Oops: 0000
> > Dec 13 01:31:18 wellhouse kernel: CPU: 0
> > Dec 13 01:31:18 wellhouse kernel: EIP: 0010:[chrdev_open+56/88]
> > Dec 13 01:31:18 wellhouse kernel: EFLAGS: 00010286
> > Dec 13 01:31:18 wellhouse kernel: eax: c8870260 ebx: ffffffed ecx:
> 00000000 edx: 000000cb
> > Dec 13 01:31:18 wellhouse kernel: esi: c34d4380 edi: c0565e60 ebp:
> c3c35900 esp: c3b47f4c
> > Dec 13 01:31:18 wellhouse kernel: ds: 0018 es: 0018 ss: 0018
> > Dec 13 01:31:18 wellhouse kernel: Process cat (pid: 1645, process nr: 53,
> stackpage=c3b47000)
> > Dec 13 01:31:18 wellhouse kernel: Stack: c0565e60 00008000 00000003
> 400e88b3 bffffa4c c012497c c0565e60 c34d4380
> > Dec 13 01:31:18 wellhouse kernel: 00000000 c01248d5 00000003
> c05a3000 400e88b3 bffffa4c 00000000 c398549c
> > Dec 13 01:31:18 wellhouse kernel: 00000400 c0124b6f c05a3000
> 00008000 00000000 c0124b56 c3b46000 40013ed0
> > Dec 13 01:31:18 wellhouse kernel: Call Trace: [filp_open+184/264]
> [filp_open+17/264] [sys_open+63/160] [sys_open+38/160] [error_code+45/64] [
> > system_call+52/64]
> > Dec 13 01:31:18 wellhouse kernel: Code: 8b 40 1c 31 db 85 c0 74 0c 83 c4
> f8 56 57 ff d0 89 c3 83 c4
> > Using defaults from ksymoops -t elf32-i386 -a i386
> >
> > Code; 00000000 Before first symbol
> > 00000000 <_EIP>:
> > Code; 00000000 Before first symbol
> > 0: 8b 40 1c mov 0x1c(%eax),%eax
> > Code; 00000003 Before first symbol
> > 3: 31 db xor %ebx,%ebx
> > Code; 00000005 Before first symbol
> > 5: 85 c0 test %eax,%eax
> > Code; 00000007 Before first symbol
> > 7: 74 0c je 15 <_EIP+0x15> 00000015 Before
> first symbol
> > Code; 00000009 Before first symbol
> > 9: 83 c4 f8 add $0xfffffff8,%esp
> > Code; 0000000c Before first symbol
> > c: 56 push %esi
> > Code; 0000000d Before first symbol
> > d: 57 push %edi
> > Code; 0000000e Before first symbol
> > e: ff d0 call *%eax
> > Code; 00000010 Before first symbol
> > 10: 89 c3 mov %eax,%ebx
> > Code; 00000012 Before first symbol
> > 12: 83 c4 00 add $0x0,%esp
> >
> >
> > 1 warning issued. Results may not be reliable.
> >
> > I know they're not exactly show-stoppers, but here they are anyway.
> > Cheers,
> > Chris
> >
>
>
> Looks like a devfs problem; complain to the appropriate people. I refuse
> to touch that particular devfs code.
I've had a quick look at both the 2.2.18 and 2.4.0-test12 drivers for
msr and cpuid, and I've noticed something curious.
This is the comment from 2.4.0-test12, cpuid.c:
/*
* cpuid.c
*
* x86 CPUID access device
*
* This device is accessed by lseek() to the appropriate CPUID level
* and then read in chunks of 16 bytes. A larger size means multiple
* reads of consecutive levels.
*
* This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on
* an SMP box will direct the access to CPU %d.
*/
And this is the initialisation function:
int __init cpuid_init(void)
{
if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
CPUID_MAJOR);
return -EBUSY;
}
return 0;
}
These two are inconsistent! I had dutifully created a /dev/cpu/0
directory on my 2.2.18 and 2.4.0-test12 boxes, and had placed cpuid
device nodes inside them. (The 2.4.0-test12 box is SMP, and so I also
created a /dev/cpu/1 directory there too.) However, the driver expects
the device node to be /dev/cpu/cpuid. The msr driver has the same
problem.
Both the cpuid and the msr modules successfully loaded on 2.2.18 when
I tried to cat /dev/cpu/cpuid and /dev/cpu/msr. (Although they both
remained flagged as (unused), which I found strange considering the
amount of output I got.)
Cheers,
Chris
OK, I've just tried repeating this experiment on 2.2.18 (no devfs) and
it oopsed this time, so there's obviously something else going on
here.
$ ksymoops -m /boot/System.map-2.2.18 < oops2.txt
ksymoops 2.3.4 on i586 2.2.18. Options used
-V (default)
-k /proc/ksyms (default)
-l /proc/modules (default)
-o /lib/modules/2.2.18/ (default)
-m /boot/System.map-2.2.18 (specified)
Warning (compare_maps): ksyms_base symbol module_list_R__ver_module_list not found in System.map. Ignoring ksyms_base entry
Dec 14 22:03:53 wellhouse kernel: Unable to handle kernel paging request at virtual address c888a27c
Dec 14 22:03:53 wellhouse kernel: current->tss.cr3 = 03003000, %%cr3 = 03003000
Dec 14 22:03:53 wellhouse kernel: *pde = 013f2063
Dec 14 22:03:53 wellhouse kernel: Oops: 0000
Dec 14 22:03:53 wellhouse kernel: CPU: 0
Dec 14 22:03:53 wellhouse kernel: EIP: 0010:[chrdev_open+56/88]
Dec 14 22:03:53 wellhouse kernel: EFLAGS: 00010286
Dec 14 22:03:53 wellhouse kernel: eax: c888a260 ebx: ffffffed ecx: 00000000 edx: 000000cb
Dec 14 22:03:53 wellhouse kernel: esi: c25ba8c0 edi: c18c2288 ebp: c3c50ca0 esp: c0ef9f4c
Dec 14 22:03:53 wellhouse kernel: ds: 0018 es: 0018 ss: 0018
Dec 14 22:03:53 wellhouse kernel: Process cat (pid: 7021, process nr: 61, stackpage=c0ef9000)
Dec 14 22:03:53 wellhouse kernel: Stack: c18c2288 00008000 00000003 400e88b3 bffffa6c c012497c c18c2288 c25ba8c0
Dec 14 22:03:53 wellhouse kernel: 00000000 c01248d5 00000003 c398a000 400e88b3 bffffa6c 00000000 c16b427c
Dec 14 22:03:53 wellhouse kernel: 00000400 c0124b6f c398a000 00008000 00000000 c0124b56 c0ef8000 40013ed0
Dec 14 22:03:53 wellhouse kernel: Call Trace: [filp_open+184/264] [filp_open+17/264] [sys_open+63/160] [sys_open+38/160] [error_code+45/64] [system_call+52/64]
Dec 14 22:03:53 wellhouse kernel: Code: 8b 40 1c 31 db 85 c0 74 0c 83 c4 f8 56 57 ff d0 89 c3 83 c4
Using defaults from ksymoops -t elf32-i386 -a i386
Code; 00000000 Before first symbol
00000000 <_EIP>:
Code; 00000000 Before first symbol
0: 8b 40 1c mov 0x1c(%eax),%eax
Code; 00000003 Before first symbol
3: 31 db xor %ebx,%ebx
Code; 00000005 Before first symbol
5: 85 c0 test %eax,%eax
Code; 00000007 Before first symbol
7: 74 0c je 15 <_EIP+0x15> 00000015 Before first symbol
Code; 00000009 Before first symbol
9: 83 c4 f8 add $0xfffffff8,%esp
Code; 0000000c Before first symbol
c: 56 push %esi
Code; 0000000d Before first symbol
d: 57 push %edi
Code; 0000000e Before first symbol
e: ff d0 call *%eax
Code; 00000010 Before first symbol
10: 89 c3 mov %eax,%ebx
Code; 00000012 Before first symbol
12: 83 c4 00 add $0x0,%esp
1 warning issued. Results may not be reliable.
Chris