Finding out which Linux process was executing when system locked up by evaluating CPU registers?

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I need to find out what is executing when my Linux (Debian) system hangs (x86 platform). I managed to extract the following information just before the system locked up: es: 0x7B cs: 0x73 ss: 0x7B ds: 0x7B fs: 0x0 gs: 0x33 ldtbase: 0x0 tr: 0x80 dr7: 0x400 dr6: 0xFFFF0FF0 eax: 0xBFBDE820 ecx: 0xA908F9A0 edx: 0xB708A000 ebx: 0xB71B5278 esp: 0xBFBDE730 ebp: 0xBFBDE838 esi: 0x9D36B58 edi: 0x9D50BB8 eip: 0xB71B13E8 eflags: 0x203206 cr3: 0x1E9DE000 cr0: 0x80050033 From the values of the segment registers, I know that when Linux hangs, it's on user-space mode. What I would like to find out is which process/library is causing the crash, and ideally which exact part of it.

By looking at CR3 and EIP, I should be able to get this information but I am getting confused. As far as I know, the virtual address 0xB71B13E8 is relative to the page table used (0x1E9DE000). Now, the instruction pointer points to a physical address, right?

I think I should convert this (EIP value) to a virtual address which would be the offset of the page table pointed by CR3. Could anyone please help me a bit on that? Linux memory-management linux-kernel memory-allocation link|improve this question asked Apr 12 '11 at 9:54limp1097 48% accept rate.

If this is a usermode crash/lockup, presumably this information is from a core dump (you can dump cores on the fly without necessarily killing the subject) In that case, use gdb /usr/bin/myprogrambinary corefile And navigate using gdb commands bt, info threads, info shared, thread apply all bt full etc The usefulness of all this will greatly improve with debugging symbols for the various libraries installed on your system (depending on your distro, install the relevant *-dbg packages).

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