Re: {multiple} Kernel Oops on cat /proc/ioports

From: Randy.Dunlap (rddunlap@osdl.org)
Date: Tue Dec 11 2001 - 19:31:34 EST


On 11 Dec 2001, Berend De Schouwer wrote:

| [1.] One line summary of the problem:
|
| Running "cat /proc/ioports" causes a segfault and kernel oops.

| >>EIP; c02a925b <vsnprintf+20b/420> <=====
| Trace; c02a94a6 <vsprintf+16/20>
| Trace; c02a94c4 <sprintf+14/20>
| Trace; c011dcfb <do_resource_list+4b/80>
| Trace; c011dd1b <do_resource_list+6b/80>
| Trace; c011dd72 <get_resource_list+42/60>
| Trace; c0154eae <ioports_read_proc+2e/60>
| Trace; c0152a3e <proc_file_read+ce/190>
| Trace; c01368f6 <sys_read+96/d0>
| Trace; c0127caa <sys_brk+ba/f0>
| Trace; c010712b <system_call+33/38>
| Code; c02a925b <vsnprintf+20b/420>
| 00000000 <_EIP>:
| Code; c02a925b <vsnprintf+20b/420> <=====
| 0: 80 38 00 cmpb $0x0,(%eax) <=====
| Code; c02a925e <vsnprintf+20e/420>
| 3: 74 07 je c <_EIP+0xc> c02a9267 <vsnprintf+217/420>
| Code; c02a9260 <vsnprintf+210/420>
| 5: 40 inc %eax
| Code; c02a9261 <vsnprintf+211/420>
| 6: 4a dec %edx
| Code; c02a9262 <vsnprintf+212/420>
| 7: 83 fa ff cmp $0xffffffff,%edx
| Code; c02a9265 <vsnprintf+215/420>
| a: 75 f4 jne 0 <_EIP>
| Code; c02a9267 <vsnprintf+217/420>
| c: 29 c8 sub %ecx,%eax
| Code; c02a9269 <vsnprintf+219/420>
| e: f6 04 24 10 testb $0x10,(%esp,1)
| Code; c02a926d <vsnprintf+21d/420>
| 12: 89 c6 mov %eax,%esi

There have been 3 reports of Oops in vsnprintf() recently [more
precisely, in inline strnlen() ]:

http://marc.theaimsgroup.com/?l=linux-kernel&m=100277148326190&w=2
  printing /proc/ioports

http://marc.theaimsgroup.com/?l=linux-kernel&m=100680451811435&w=2
  usb device connect/disconnect

http://marc.theaimsgroup.com/?l=linux-kernel&m=100807421108830&w=2
  printing /proc/ioports

It would be easy to paste over the problem in vsnprintf(), but
they indicate to me that something else is screwy.

-- 
~Randy

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