Re: 2.6.37-rc7: Regression: b43: crashes in hwrng_register()

Mario 'BitKoenig' Holbe
2010-12-30T14:34:21Z

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On Wed, Dec 29, 2010 at 08:37:10PM -0600, Larry Finger wrote:
> No, don't bother. I do have a different request. The byte counts for my 32-bit
> system do not match yours. Could you please use the following command to find
> the instructions that are failing?
>
> objdump -l -d drivers/char/hw_random/core.o | less
>
> Use the search to find the start of hwrng_register, then add 0x4c to the
> starting address. Once I see hte instruction that is failing, I should be able
> to find where the failure occurs.

Alright, here we go...

[ 30.012695] BUG: unable to handle kernel paging request at 4b28f458
[ 30.012708] IP: [<f90703cc>] hwrng_register+0x4c/0x139 [rng_core]

00000380 <hwrng_register>:
hwrng_register():
/tmp/1/linux-source-2.6.37-rc7/drivers/char/hw_random/core.c:299
380: 56 push %esi
381: 53 push %ebx
...
/tmp/1/linux-source-2.6.37-rc7/drivers/char/hw_random/core.c:312
3c6: 8b 76 1c mov 0x1c(%esi),%esi
3c9: 83 ee 1c sub $0x1c,%esi
prefetch():
/tmp/1/linux-source-2.6.37-rc7/arch/x86/include/asm/processor.h:837
3cc: 8b 46 1c mov 0x1c(%esi),%eax
3cf: 8d 74 26 00 lea 0x0(%esi,%eiz,1),%esi
hwrng_register():
/tmp/1/linux-source-2.6.37-rc7/drivers/char/hw_random/core.c:312
3d3: 81 fe f8 ff ff ff cmp $0xfffffff8,%esi
3d9: 75 d4 jne 3af <hwrng_register+0x2f>
/tmp/1/linux-source-2.6.37-rc7/drivers/char/hw_random/core.c:319

312 list_for_each_entry(tmp, &rng_list, list) {
313 if (strcmp(tmp->name, rng->name) == 0)
314 goto out_unlock;
315 }

This is btw. the same data that is accessed in the cat rng_available
crash via hwrng_attr_available_show():

[ 389.303538] BUG: unable to handle kernel paging request at 288dcb5b
[ 389.303553] IP: [<f8dda34c>] hwrng_attr_available_show+0x5c/0x90 [rng_core]

000002f0 <hwrng_attr_available_show>:
hwrng_attr_available_show():
/tmp/1/linux-source-2.6.37-rc7/drivers/char/hw_random/core.c:236
2f0: 55 push %ebp
...
/tmp/1/linux-source-2.6.37-rc7/drivers/char/hw_random/core.c:245
346: 8b 5b 1c mov 0x1c(%ebx),%ebx
349: 83 eb 1c sub $0x1c,%ebx
prefetch():
/tmp/1/linux-source-2.6.37-rc7/arch/x86/include/asm/processor.h:837
34c: 8b 43 1c mov 0x1c(%ebx),%eax
34f: 8d 74 26 00 lea 0x0(%esi,%eiz,1),%esi
hwrng_attr_available_show():
/tmp/1/linux-source-2.6.37-rc7/drivers/char/hw_random/core.c:245

245 list_for_each_entry(rng, &rng_list, list) {
246 strncat(buf, rng->name, PAGE_SIZE - ret - 1);
247 ret += strlen(rng->name);
248 strncat(buf, " ", PAGE_SIZE - ret - 1);
249 ret++;
250 }

regards
Mario
--
The problem in the world today is communication. Too much communication.
-- Homer J. Simpson

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