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We're struggling all the time to figure out where the code came from that
oopsed.. The script below (a adaption from a script used by
kerneloops.org) can help developers quite a bit, at least for non-module
cases.
It works and looks like this:
[/home/arjan/linux]$ dmesg | perl scripts/markup_oops.pl vmlinux
{
struct agp_memory *memory;
memory = agp_allocate_memory(agp_bridge, pg_count, type);
c055c10f: 89 c2 mov %eax,%edx
if (memory == NULL)
c055c111: 74 19 je c055c12c <agp_allocate_memory_wrap+0x30>
/* This function must only be called when current_controller != NULL */
static void agp_insert_into_pool(struct agp_memory * temp)
{
struct agp_memory *prev;
prev = agp_fe.current_controller->pool;
c055c113: a1 ec dc 8f c0 mov 0xc08fdcec,%eax
*c055c118: 8b 40 10 mov 0x10(%eax),%eax <----- faulting instruction
if (prev != NULL) {
c055c11b: 85 c0 test %eax,%eax
c055c11d: 74 05 je c055c124 <agp_allocate_memory_wrap+0x28>
prev->prev = temp;
c055c11f: 89 50 04 mov %edx,0x4(%eax)
temp->next = prev;
c055c122: 89 02 mov %eax,(%edx)
}
agp_fe.current_controller->pool = temp;
c055c124: a1 ec dc 8f c0 mov 0xc08fdcec,%eax
c055c129: 89 50 10 mov %edx,0x10(%eax)
if (memory == NULL)
return NULL;
agp_insert_into_pool(memory);
so in this case, we faulted while dereferencing agp_fe.current_controller
pointer, and we get to see exactly which function and line it affects...
Personally I find this very useful, and I can see value for having this
script in the kernel for more-than-just-me to use.
Caveats:
* It only works for oopses not-in-modules
* It only works nicely for kernels compiled with CONFIG_DEBUG_INFO
* It's not very fast.
* It only works on x86
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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