klibc - Jun 2012 - Bug#634890: klibc issues on armhf (not Debian/armel)

On Tue, 19 Jun 2012, Steve McIntyre wrote:
> 
> More debugging results:
> 
>  * If I replace -Os with -O0 to disable optimisation, the crash goes
>    away too. Suggests (maybe) a compiler bug here...
nasty. :|
 
>  * There's a real bug in the ARM assembly version of longjmp in
>    usr/klibc/arch/arm/setjmp.S: it will always pass back its first
>    argument as a return value, even if it's 0 (see the man page for
>    more details). Oddly, the Thumb implementation in the same file
>    *is* correct!
care to cook up a patch, please?

thank you.

-- 
maks

On Thu, Jun 28, 2012 at 06:59:34PM +0200, maximilian attems
wrote:
>On Tue, 19 Jun 2012, Steve McIntyre wrote:
>
>> 
>> More debugging results:
>> 
>>  * If I replace -Os with -O0 to disable optimisation, the crash goes
>>    away too. Suggests (maybe) a compiler bug here...
>
>nasty. :|
> 
>>  * There's a real bug in the ARM assembly version of longjmp in
>>    usr/klibc/arch/arm/setjmp.S: it will always pass back its first
>>    argument as a return value, even if it's 0 (see the man page for
>>    more details). Oddly, the Thumb implementation in the same file
>>    *is* correct!
>
>care to cook up a patch, please?
Sure, no problem:

--- klibc-2.0.old/usr/klibc/arch/arm/setjmp.S   2012-05-29 21:41:34.000000000
+0000
+++ klibc-2.0/usr/klibc/arch/arm/setjmp.S       2012-06-29 16:53:25.000000000
+0000
@@ -41,7 +41,9 @@
 longjmp:
        ldmia   r0, {r4, r5, r6, r7, r8, r9, r10, fp, sp, lr}
        mov     r0, r1
-       BX(lr)
+       bne     1f
+       mov     r0, #1
+1:     BX(lr)
        .size longjmp,.-longjmp
 
 #else /* __thumb__ */


-- 
Steve McIntyre, Cambridge, UK.                                steve at
einval.com
You lock the door
And throw away the key
There's someone in my head but it's not me