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

On 3/14/24 00:57, Geert Uytterhoeven wrote:

Hi Günter,

On Tue, Mar 12, 2024 at 6:06 PM Guenter Roeck [off-list ref] wrote:

quoted

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!

quoted

--- 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