Hi, While using kfree on a list ndoe being maintained by me, at times I get a Oops message, kfree(node) calls __kmem_cache_free which in turn calls kmem_cache_free_one (), the EIP shown in /var/log/messages and ksymoops shows the EIP as c012d8fe, this is in kmem_cache_free_one() function. This is difficult to reproduce, hence I am confused as to what may be going wrong. At this EIP what is done is 0xC(%ebx), %ecx Warning (map_ksym_to_module): cannot match loaded module ext3 to a unique module object. Trace may not be reliable. Aug 18 22:09:03 localhost kernel: Unable to handle kernel NULL pointer dereference at virtual address 0000000c Aug 18 22:09:03 localhost kernel: c012d8fe Aug 18 22:09:03 localhost kernel: *pde = 00000000 Aug 18 22:09:03 localhost kernel: Oops: 0000 Aug 18 22:09:03 localhost kernel: CPU: 0 Aug 18 22:09:03 localhost kernel: EIP: 0010:[<c012d8fe>] Not tainted Using defaults from ksymoops -t elf32-i386 -a i386 Aug 18 22:09:03 localhost kernel: EFLAGS: 00013003 Aug 18 22:09:03 localhost kernel: eax: c100001c ebx: 00000000 ecx: d09c7e40 edx: 000b6b8d Aug 18 22:09:03 localhost kernel: esi: c1e3e740 edi: 00000000 ebp: c8515e88 esp: c8515e44 Aug 18 22:09:03 localhost kernel: ds: 0018 es: 0018 ss: 0018 Aug 18 22:09:03 localhost kernel: Process itcp (pid: 3198, stackpage=c8515000) Aug 18 22:09:03 localhost kernel: Stack: 00003282 c1e3e740 c012d379 00000000 d09c7e40 d09c7e40 d09c5e6a d09c7e40 Aug 18 22:09:03 localhost kernel: d09c61e2 000001d0 d09c6239 cff76f74 00003246 c1e3e740 c57d7350 cff73350 Aug 18 22:09:03 localhost kernel: cccac340 cc42b890 c0135ca2 cccac340 c57d7350 c57d7350 ca28d400 00000000 Aug 18 22:09:03 localhost kernel: Call Trace: [<c012d379>] [<d09c7e40>] [<d09c7e40>] [<d09c5e6a>] [<d09c7e40>] Aug 18 22:09:03 localhost kernel: [<d09c61e2>] [<d09c6239>] [<c0135ca2>] [<c01347d7>] [<c011a1ab>] [<c011a778>] Aug 18 22:09:03 localhost kernel: [<c011fd24>] [<c010861d>] [<c012d379>] [<c0142ceb>] [<c011bdeb>] [<c01150ba>] Aug 18 22:09:03 localhost kernel: [<c01088b8>] Aug 18 22:09:03 localhost kernel: Code: 2b 4b 0c 8b 74 24 0c 89 c8 31 d2 f7 76 18 89 c1 8b 43 14 >>EIP; c012d8fe <kmem_cache_free_one+1e/93> <===== >>eax; c100001c <_end+cf9464/105064a8> >>ecx; d09c7e40 <.data.end+1b9/????> >>esi; c1e3e740 <_end+1b37b88/105064a8> >>ebp; c8515e88 <_end+820f2d0/105064a8> >>esp; c8515e44 <_end+820f28c/105064a8> Trace; c012d379 <kfree+29/30> Trace; d09c7e40 <.data.end+1b9/????> Trace; d09c7e40 <.data.end+1b9/????> Trace; d09c5e6a <[pktcdrv]char_dev_close+176/195> Trace; d09c7e40 <.data.end+1b9/????> Trace; d09c61e2 <[pktcdrv]__module_kernel_version+ea/1b08> Trace; d09c6239 <[pktcdrv]__module_kernel_version+141/1b08> Trace; c0135ca2 <fput+d6/f4> Trace; c01347d7 <filp_close+37/58> Trace; c011a1ab <put_files_struct+6b/c0> Trace; c011a778 <do_exit+a0/204> Trace; c011fd24 <block_all_signals+0/2c> Trace; c010861d <do_signal+195/254> Trace; c012d379 <kfree+29/30> Trace; c0142ceb <sys_select+307/598> Trace; c011bdeb <tasklet_action+3b/5c> Trace; c01150ba <schedule+1ee/31c> Trace; c01088b8 <signal_return+14/18> Code; c012d8fe <kmem_cache_free_one+1e/93> 00000000 <_EIP>: Code; c012d8fe <kmem_cache_free_one+1e/93> <===== 0: 2b 4b 0c sub 0xc(%ebx),%ecx <===== Code; c012d901 <kmem_cache_free_one+21/93> 3: 8b 74 24 0c mov 0xc(%esp,1),%esi Code; c012d905 <kmem_cache_free_one+25/93> 7: 89 c8 mov %ecx,%eax Code; c012d907 <kmem_cache_free_one+27/93> 9: 31 d2 xor %edx,%edx Code; c012d909 <kmem_cache_free_one+29/93> b: f7 76 18 divl 0x18(%esi) Code; c012d90c <kmem_cache_free_one+2c/93> e: 89 c1 mov %eax,%ecx Code; c012d90e <kmem_cache_free_one+2e/93> 10: 8b 43 14 mov 0x14(%ebx),%eax 1 warning and 2 errors issued. Results may not be reliable. ***************** HSS-Unclassified ************* "DISCLAIMER: This message is proprietary to Hughes Software Systems Limited (HSS) and is intended solely for the use of the individual to whom it is addressed. It may contain privileged or confidential information and should not be circulated or used for any purpose other than for what it is intended. If you have received this message in error, please notify the originator immediately. If you are not the intended recipient, you are notified that you are strictly prohibited from using, copying, altering, or disclosing the contents of this message. HSS accepts no responsibility for loss or damage arising from the use of the information transmitted by this email including damage from virus." -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
