Re: [PATCH 11/14] s390: Add support for suppressing warning backtraces

Guenter Roeck
2024-03-14T13:54:36Z

On 3/14/24 00:57, Geert Uytterhoeven wrote:
> Hi Günter,
>
> On Tue, Mar 12, 2024 at 6:06 PM Guenter Roeck <linux@roeck-us.net> wrote:
>> Add name of functions triggering warning backtraces to the __bug_table
>> object section to enable support for suppressing WARNING backtraces.
>>
>> To limit image size impact, the pointer to the function name is only added
>> to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE
>> are enabled. Otherwise, the __func__ assembly parameter is replaced with a
>> (dummy) NULL parameter to avoid an image size increase due to unused
>> __func__ entries (this is necessary because __func__ is not a define but a
>> virtual variable).
>>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>
> Thanks for your patch!
>
>> --- a/arch/s390/include/asm/bug.h
>> +++ b/arch/s390/include/asm/bug.h
>> @@ -8,19 +8,30 @@
>>
>> #ifdef CONFIG_DEBUG_BUGVERBOSE
>>
>> +#if IS_ENABLED(CONFIG_KUNIT)
>> +# define HAVE_BUG_FUNCTION
>> +# define __BUG_FUNC_PTR " .long %0-.\n"
>> +# define __BUG_FUNC __func__
>> +#else
>> +# define __BUG_FUNC_PTR
>> +# define __BUG_FUNC NULL
>> +#endif /* IS_ENABLED(CONFIG_KUNIT) */
>> +
>> #define __EMIT_BUG(x) do { \
>> asm_inline volatile( \
>> "0: mc 0,0\n" \
>> ".section .rodata.str,\"aMS\",@progbits,1\n" \
>> "1: .asciz \""__FILE__"\"\n" \
>> ".previous\n" \
>> - ".section __bug_table,\"awM\",@progbits,%2\n" \
>> + ".section __bug_table,\"awM\",@progbits,%3\n" \
>
> This change conflicts with commit 3938490e78f443fb ("s390/bug:
> remove entry size from __bug_table section") in linus/master.
> I guess it should just be dropped?
>

Yes, I know. I'll send v2 rebased to v6.9-rc1 once it is available and,
yes, the change will be gone after that.

Thanks,
Guenter