[PATCH 00/14] Improve WARN_ON_ONCE() output by adding the condition string

[PATCH 00/14] Improve WARN_ON_ONCE() output by adding the condition string

[Ingo Molnar]

This series improves the current WARN_ON_ONCE() output from:

  WARN_ON_ONCE(idx < 0 && ptr);
  ...

  WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:8511 sched_init+0x20/0x410

to (on all __WARN_FLAGS() using architectures except S390):

  WARNING: [idx < 0 && ptr] kernel/sched/core.c:8511 at sched_init+0x20/0x410 CPU#0: swapper/0

(Note the addition of the '[condition string]', and a reorganized CPU/comm/PID trailer.)

... and on S390 and non-__WARN_FLAGS architectures to:

  WARNING: kernel/sched/core.c:8511 at sched_init+0x20/0x410 CPU#0: swapper/0

and on non-x86 architectures (the CPU/PID fields in the WARNING line are skipped):

  WARNING: kernel/sched/core.c:8511 sched_init+0x20/0x410
  CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.14.0-01616-g94d7af2844aa #4 PREEMPT(undef)

The motivation behind this series is the SCHED_WARN_ON() primitive that
got removed in this merge window:

  f7d2728cc032 ("sched/debug: Change SCHED_WARN_ON() to WARN_ON_ONCE()")

... which produced more informative debug output, as it included the
WARN_ON_ONCE() condition string - at the expense of worse code generation.

This series, based on Linus's latest Git tree, merges the code generation
benefits of modern WARN_ON_ONCE() bug_entry architecture code with the expanded
information content of SCHED_WARN_ON().

The cost is about +100K more .data on a defconfig kernel, and no runtime
code generation impact:

       text       data        bss         dec        hex    filename
   29523998    7926322    1389904    38840224    250a7a0    vmlinux.x86.defconfig.before
   29523998    8024626    1389904    38938528    25227a0    vmlinue.x86.defconfig.after

The series was build and boot tested on x86, with an expectation for it to
work on other architectures (with limited cross-testing on the affected
architectures).

This tree can also be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip WIP.core/bugs

Thanks,

    Ingo

================>

Ingo Molnar (14):
  bugs/core: Extend __WARN_FLAGS() with the 'cond_str' parameter
  bugs/core: Pass down the condition string of WARN_ON_ONCE(cond) warnings to __WARN_FLAGS()
  bugs/x86: Extend _BUG_FLAGS() with the 'cond_str' parameter
  bugs/x86: Augment warnings output by concatenating 'cond_str' with the regular __FILE__ string in _BUG_FLAGS()
  bugs/powerpc: Pass in 'cond_str' to BUG_ENTRY()
  bugs/powerpc: Concatenate 'cond_str' with '__FILE__' in BUG_ENTRY(), to extend WARN_ON/BUG_ON output
  bugs/LoongArch: Pass in 'cond_str' to __BUG_ENTRY()
  bugs/LoongArch: Concatenate 'cond_str' with '__FILE__' in __BUG_ENTRY(), to extend WARN_ON/BUG_ON output
  bugs/s390: Pass in 'cond_str' to __EMIT_BUG()
  bugs/riscv: Pass in 'cond_str' to __BUG_FLAGS()
  bugs/riscv: Concatenate 'cond_str' with '__FILE__' in __BUG_FLAGS(), to extend WARN_ON/BUG_ON output
  bugs/parisc: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output
  bugs/sh: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output
  bugs/core: Reorganize fields in the first line of WARNING output, add ->comm[] output

 arch/arm64/include/asm/bug.h     |  2 +-
 arch/loongarch/include/asm/bug.h | 25 ++++++++++++-------------
 arch/parisc/include/asm/bug.h    |  6 +++---
 arch/powerpc/include/asm/bug.h   | 12 ++++++------
 arch/riscv/include/asm/bug.h     | 10 +++++-----
 arch/s390/include/asm/bug.h      | 10 +++++-----
 arch/sh/include/asm/bug.h        |  4 ++--
 arch/x86/include/asm/bug.h       | 14 +++++++-------
 include/asm-generic/bug.h        |  7 ++++---
 kernel/panic.c                   | 16 +++++++++-------
 10 files changed, 54 insertions(+), 52 deletions(-)

-- 
2.45.2

[PATCH 01/14] bugs/core: Extend __WARN_FLAGS() with the 'cond_str' parameter

[Ingo Molnar]

Push the new parameter down into every architecture that defines __WARN_FLAGS():

  arm64
  loongarch
  parisc
  powerpc
  riscv
  s390
  sh
  x86

Don't pass anything substantial down yet, just propagate the
new parameter with empty strings, without generating it or
using it.

( The string is never NULL, so it can be concatenated at the
  preprocessor level. )

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <linux-arch@vger.kernel.org>
---
 arch/arm64/include/asm/bug.h     | 2 +-
 arch/loongarch/include/asm/bug.h | 2 +-
 arch/parisc/include/asm/bug.h    | 4 ++--
 arch/powerpc/include/asm/bug.h   | 2 +-
 arch/riscv/include/asm/bug.h     | 2 +-
 arch/s390/include/asm/bug.h      | 2 +-
 arch/sh/include/asm/bug.h        | 2 +-
 arch/x86/include/asm/bug.h       | 2 +-
 include/asm-generic/bug.h        | 7 ++++---
 9 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/bug.h b/arch/arm64/include/asm/bug.h
index 28be048db3f6..bceeaec21fb9 100644
--- a/arch/arm64/include/asm/bug.h
+++ b/arch/arm64/include/asm/bug.h
@@ -19,7 +19,7 @@
 	unreachable();					\
 } while (0)
 
-#define __WARN_FLAGS(flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
+#define __WARN_FLAGS(cond_str, flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
 
 #define HAVE_ARCH_BUG
 
diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
index f6f254f2c5db..51c2cb98d728 100644
--- a/arch/loongarch/include/asm/bug.h
+++ b/arch/loongarch/include/asm/bug.h
@@ -42,7 +42,7 @@
 	asm_inline volatile (__stringify(ASM_BUG_FLAGS(flags))		\
 			     extra);
 
-#define __WARN_FLAGS(flags)					\
+#define __WARN_FLAGS(cond_str, flags)				\
 do {								\
 	instrumentation_begin();				\
 	__BUG_FLAGS(BUGFLAG_WARNING|(flags), ANNOTATE_REACHABLE(10001b));\
diff --git a/arch/parisc/include/asm/bug.h b/arch/parisc/include/asm/bug.h
index 833555f74ffa..1a87cf80ec3c 100644
--- a/arch/parisc/include/asm/bug.h
+++ b/arch/parisc/include/asm/bug.h
@@ -50,7 +50,7 @@
 #endif
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
-#define __WARN_FLAGS(flags)						\
+#define __WARN_FLAGS(cond_str, flags)					\
 	do {								\
 		asm volatile("\n"					\
 			     "1:\t" PARISC_BUG_BREAK_ASM "\n"		\
@@ -66,7 +66,7 @@
 			     "i" (sizeof(struct bug_entry)) );		\
 	} while(0)
 #else
-#define __WARN_FLAGS(flags)						\
+#define __WARN_FLAGS(cond_str, flags)					\
 	do {								\
 		asm volatile("\n"					\
 			     "1:\t" PARISC_BUG_BREAK_ASM "\n"		\
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 1db485aacbd9..34d39ec79720 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -72,7 +72,7 @@
 } while (0)
 #define HAVE_ARCH_BUG
 
-#define __WARN_FLAGS(flags) BUG_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags))
+#define __WARN_FLAGS(cond_str, flags) BUG_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags))
 
 #ifdef CONFIG_PPC64
 #define BUG_ON(x) do {						\
diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
index 1aaea81fb141..b22ee4d2c882 100644
--- a/arch/riscv/include/asm/bug.h
+++ b/arch/riscv/include/asm/bug.h
@@ -76,7 +76,7 @@ do {								\
 	unreachable();						\
 } while (0)
 
-#define __WARN_FLAGS(flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
+#define __WARN_FLAGS(cond_str, flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
 
 #define HAVE_ARCH_BUG
 
diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h
index c500d45fb465..ef3e495ec1e3 100644
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -46,7 +46,7 @@
 	unreachable();					\
 } while (0)
 
-#define __WARN_FLAGS(flags) do {			\
+#define __WARN_FLAGS(cond_str, flags) do {		\
 	__EMIT_BUG(BUGFLAG_WARNING|(flags));		\
 } while (0)
 
diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
index 05a485c4fabc..834c621ab249 100644
--- a/arch/sh/include/asm/bug.h
+++ b/arch/sh/include/asm/bug.h
@@ -52,7 +52,7 @@ do {							\
 	unreachable();					\
 } while (0)
 
-#define __WARN_FLAGS(flags)				\
+#define __WARN_FLAGS(cond_str, flags)			\
 do {							\
 	__asm__ __volatile__ (				\
 		"1:\t.short %O0\n"			\
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index f0e9acf72547..413b86b876d9 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -92,7 +92,7 @@ do {								\
  * were to trigger, we'd rather wreck the machine in an attempt to get the
  * message out than not know about it.
  */
-#define __WARN_FLAGS(flags)					\
+#define __WARN_FLAGS(cond_str, flags)				\
 do {								\
 	__auto_type __flags = BUGFLAG_WARNING|(flags);		\
 	instrumentation_begin();				\
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 387720933973..af76e4a04b16 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -100,17 +100,18 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
 		instrumentation_end();					\
 	} while (0)
 #else
-#define __WARN()		__WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
+#define __WARN()		__WARN_FLAGS("", BUGFLAG_TAINT(TAINT_WARN))
 #define __WARN_printf(taint, arg...) do {				\
 		instrumentation_begin();				\
 		__warn_printk(arg);					\
-		__WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\
+		__WARN_FLAGS("", BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\
 		instrumentation_end();					\
 	} while (0)
 #define WARN_ON_ONCE(condition) ({				\
 	int __ret_warn_on = !!(condition);			\
 	if (unlikely(__ret_warn_on))				\
-		__WARN_FLAGS(BUGFLAG_ONCE |			\
+		__WARN_FLAGS("",				\
+			     BUGFLAG_ONCE |			\
 			     BUGFLAG_TAINT(TAINT_WARN));	\
 	unlikely(__ret_warn_on);				\
 })
-- 
2.45.2

[PATCH 02/14] bugs/core: Pass down the condition string of WARN_ON_ONCE(cond) warnings to __WARN_FLAGS()

[Ingo Molnar]

Doing this will allow architecture code to store and print out
this information as part of the WARN_ON and BUG_ON facilities.

The format of the string is '[condition]', for example:

  WARN_ON_ONCE(idx < 0 && ptr);

Will get the '[idx < 0 && ptr]' string literal passed down as 'cond_str'
in __WARN_FLAGS().

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <linux-arch@vger.kernel.org>
---
 include/asm-generic/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index af76e4a04b16..c8e7126bc26e 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -110,7 +110,7 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
 #define WARN_ON_ONCE(condition) ({				\
 	int __ret_warn_on = !!(condition);			\
 	if (unlikely(__ret_warn_on))				\
-		__WARN_FLAGS("",				\
+		__WARN_FLAGS("["#condition"] ",			\
 			     BUGFLAG_ONCE |			\
 			     BUGFLAG_TAINT(TAINT_WARN));	\
 	unlikely(__ret_warn_on);				\
-- 
2.45.2

[PATCH 03/14] bugs/x86: Extend _BUG_FLAGS() with the 'cond_str' parameter

[Ingo Molnar]

Just pass down the parameter, don't do anything with it yet.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <linux-arch@vger.kernel.org>
---
 arch/x86/include/asm/bug.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index 413b86b876d9..aff1c6b7a7f3 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -39,7 +39,7 @@
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 
-#define _BUG_FLAGS(ins, flags, extra)					\
+#define _BUG_FLAGS(cond_str, ins, flags, extra)				\
 do {									\
 	asm_inline volatile("1:\t" ins "\n"				\
 		     ".pushsection __bug_table,\"aw\"\n"		\
@@ -57,7 +57,7 @@ do {									\
 
 #else /* !CONFIG_DEBUG_BUGVERBOSE */
 
-#define _BUG_FLAGS(ins, flags, extra)					\
+#define _BUG_FLAGS(cond_str, ins, flags, extra)				\
 do {									\
 	asm_inline volatile("1:\t" ins "\n"				\
 		     ".pushsection __bug_table,\"aw\"\n"		\
@@ -74,7 +74,7 @@ do {									\
 
 #else
 
-#define _BUG_FLAGS(ins, flags, extra)  asm volatile(ins)
+#define _BUG_FLAGS(cond_str, ins, flags, extra)  asm volatile(ins)
 
 #endif /* CONFIG_GENERIC_BUG */
 
@@ -82,7 +82,7 @@ do {									\
 #define BUG()							\
 do {								\
 	instrumentation_begin();				\
-	_BUG_FLAGS(ASM_UD2, 0, "");				\
+	_BUG_FLAGS("", ASM_UD2, 0, "");				\
 	__builtin_unreachable();				\
 } while (0)
 
@@ -96,7 +96,7 @@ do {								\
 do {								\
 	__auto_type __flags = BUGFLAG_WARNING|(flags);		\
 	instrumentation_begin();				\
-	_BUG_FLAGS(ASM_UD2, __flags, ANNOTATE_REACHABLE(1b));	\
+	_BUG_FLAGS(cond_str, ASM_UD2, __flags, ANNOTATE_REACHABLE(1b)); \
 	instrumentation_end();					\
 } while (0)
 
-- 
2.45.2

[PATCH 04/14] bugs/x86: Augment warnings output by concatenating 'cond_str' with the regular __FILE__ string in _BUG_FLAGS()

[Ingo Molnar]

This allows the reuse of the UD2 based 'struct bug_entry' low-overhead
_BUG_FLAGS() implementation and string-printing backend, without
having to add a new field.

An example:

If we have the following WARN_ON_ONCE() in kernel/sched/core.c:

	WARN_ON_ONCE(idx < 0 && ptr);

Then previously _BUG_FLAGS() would store this string in bug_entry::file:

	"kernel/sched/core.c"

After this patch, it would store and print:

	"[idx < 0 && ptr] kernel/sched/core.c"

Which is an extended string that will be printed in warnings.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <linux-arch@vger.kernel.org>
---
 arch/x86/include/asm/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index aff1c6b7a7f3..e966199c8ef7 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -50,7 +50,7 @@ do {									\
 		     "\t.org 2b+%c3\n"					\
 		     ".popsection\n"					\
 		     extra						\
-		     : : "i" (__FILE__), "i" (__LINE__),		\
+		     : : "i" (cond_str __FILE__), "i" (__LINE__),		\
 			 "i" (flags),					\
 			 "i" (sizeof(struct bug_entry)));		\
 } while (0)
-- 
2.45.2

[PATCH 05/14] bugs/powerpc: Pass in 'cond_str' to BUG_ENTRY()

[Ingo Molnar]

Pass in the condition string from __WARN_FLAGS(), WARN_ON()
and BUG_ON(), but don't use it yet.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: <linux-arch@vger.kernel.org>
---
 arch/powerpc/include/asm/bug.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 34d39ec79720..b5537ba176b5 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -51,7 +51,7 @@
 	".previous\n"
 #endif
 
-#define BUG_ENTRY(insn, flags, ...)			\
+#define BUG_ENTRY(cond_str, insn, flags, ...)		\
 	__asm__ __volatile__(				\
 		"1:	" insn "\n"			\
 		_EMIT_BUG_ENTRY				\
@@ -67,12 +67,12 @@
  */
 
 #define BUG() do {						\
-	BUG_ENTRY("twi 31, 0, 0", 0);				\
+	BUG_ENTRY("", "twi 31, 0, 0", 0);			\
 	unreachable();						\
 } while (0)
 #define HAVE_ARCH_BUG
 
-#define __WARN_FLAGS(cond_str, flags) BUG_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags))
+#define __WARN_FLAGS(cond_str, flags) BUG_ENTRY(cond_str, "twi 31, 0, 0", BUGFLAG_WARNING | (flags))
 
 #ifdef CONFIG_PPC64
 #define BUG_ON(x) do {						\
@@ -80,7 +80,7 @@
 		if (x)						\
 			BUG();					\
 	} else {						\
-		BUG_ENTRY(PPC_TLNEI " %4, 0", 0, "r" ((__force long)(x)));	\
+		BUG_ENTRY(#x, PPC_TLNEI " %4, 0", 0, "r" ((__force long)(x)));	\
 	}							\
 } while (0)
 
@@ -90,7 +90,7 @@
 		if (__ret_warn_on)				\
 			__WARN();				\
 	} else {						\
-		BUG_ENTRY(PPC_TLNEI " %4, 0",			\
+		BUG_ENTRY(#x, PPC_TLNEI " %4, 0",			\
 			  BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN),	\
 			  "r" (__ret_warn_on));	\
 	}							\
-- 
2.45.2

[PATCH 06/14] bugs/powerpc: Concatenate 'cond_str' with '__FILE__' in BUG_ENTRY(), to extend WARN_ON/BUG_ON output

[Ingo Molnar]

Extend WARN_ON and BUG_ON style output from:

  WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:8511 sched_init+0x20/0x410

to:

  WARNING: CPU: 0 PID: 0 at [idx < 0 && ptr] kernel/sched/core.c:8511 sched_init+0x20/0x410

Note that the output will be further reorganized later in this series.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: <linux-arch@vger.kernel.org>
---
 arch/powerpc/include/asm/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index b5537ba176b5..a2120fbedd09 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -55,7 +55,7 @@
 	__asm__ __volatile__(				\
 		"1:	" insn "\n"			\
 		_EMIT_BUG_ENTRY				\
-		: : "i" (__FILE__), "i" (__LINE__),	\
+		: : "i" (cond_str __FILE__), "i" (__LINE__),	\
 		  "i" (flags),				\
 		  "i" (sizeof(struct bug_entry)),	\
 		  ##__VA_ARGS__)
-- 
2.45.2

[PATCH 07/14] bugs/LoongArch: Pass in 'cond_str' to __BUG_ENTRY()

[Ingo Molnar]

Pass in the condition string from __WARN_FLAGS(), but don't use it yet.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: <linux-arch@vger.kernel.org>
---
 arch/loongarch/include/asm/bug.h | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
index 51c2cb98d728..3c377984457d 100644
--- a/arch/loongarch/include/asm/bug.h
+++ b/arch/loongarch/include/asm/bug.h
@@ -20,39 +20,38 @@
 #endif
 
 #ifndef CONFIG_GENERIC_BUG
-#define __BUG_ENTRY(flags)
+#define __BUG_ENTRY(cond_str, flags)
 #else
-#define __BUG_ENTRY(flags) 					\
+#define __BUG_ENTRY(cond_str, flags)				\
 		.pushsection __bug_table, "aw";			\
 		.align 2;					\
 	10000:	.long 10001f - .;				\
 		_BUGVERBOSE_LOCATION(__FILE__, __LINE__)	\
-		.short flags; 					\
+		.short flags;					\
 		.popsection;					\
 	10001:
 #endif
 
-#define ASM_BUG_FLAGS(flags)					\
-	__BUG_ENTRY(flags)					\
+#define ASM_BUG_FLAGS(cond_str, flags)				\
+	__BUG_ENTRY(cond_str, flags)				\
 	break		BRK_BUG;
 
-#define ASM_BUG()	ASM_BUG_FLAGS(0)
+#define ASM_BUG()	ASM_BUG_FLAGS("", 0)
 
-#define __BUG_FLAGS(flags, extra)					\
-	asm_inline volatile (__stringify(ASM_BUG_FLAGS(flags))		\
-			     extra);
+#define __BUG_FLAGS(cond_str, flags, extra)			\
+	asm_inline volatile (__stringify(ASM_BUG_FLAGS(cond_str, flags)) extra);
 
 #define __WARN_FLAGS(cond_str, flags)				\
 do {								\
 	instrumentation_begin();				\
-	__BUG_FLAGS(BUGFLAG_WARNING|(flags), ANNOTATE_REACHABLE(10001b));\
+	__BUG_FLAGS(cond_str, BUGFLAG_WARNING|(flags), ANNOTATE_REACHABLE(10001b));\
 	instrumentation_end();					\
 } while (0)
 
 #define BUG()							\
 do {								\
 	instrumentation_begin();				\
-	__BUG_FLAGS(0, "");					\
+	__BUG_FLAGS("", 0, "");					\
 	unreachable();						\
 } while (0)
 
-- 
2.45.2

[PATCH 08/14] bugs/LoongArch: Concatenate 'cond_str' with '__FILE__' in __BUG_ENTRY(), to extend WARN_ON/BUG_ON output

[Ingo Molnar]

Extend WARN_ON and BUG_ON style output from:

  WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:8511 sched_init+0x20/0x410

to:

  WARNING: CPU: 0 PID: 0 at [idx < 0 && ptr] kernel/sched/core.c:8511 sched_init+0x20/0x410

Note that the output will be further reorganized later in this series.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: <linux-arch@vger.kernel.org>
---
 arch/loongarch/include/asm/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
index 3c377984457d..305b3746c858 100644
--- a/arch/loongarch/include/asm/bug.h
+++ b/arch/loongarch/include/asm/bug.h
@@ -26,7 +26,7 @@
 		.pushsection __bug_table, "aw";			\
 		.align 2;					\
 	10000:	.long 10001f - .;				\
-		_BUGVERBOSE_LOCATION(__FILE__, __LINE__)	\
+		_BUGVERBOSE_LOCATION(cond_str __FILE__, __LINE__) \
 		.short flags;					\
 		.popsection;					\
 	10001:
-- 
2.45.2

[PATCH 09/14] bugs/s390: Pass in 'cond_str' to __EMIT_BUG()

[Ingo Molnar]

Pass in the condition string from __WARN_FLAGS(), but do not
concatenate it with __FILE__, because the __bug_table is
apparently indexed by 16 bits and increasing string size
overflows it on defconfig builds.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: <linux-arch@vger.kernel.org>
---
 arch/s390/include/asm/bug.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h
index ef3e495ec1e3..30f8785a01f5 100644
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -8,7 +8,7 @@
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 
-#define __EMIT_BUG(x) do {					\
+#define __EMIT_BUG(cond_str, x) do {				\
 	asm_inline volatile(					\
 		"0:	mc	0,0\n"				\
 		".section .rodata.str,\"aMS\",@progbits,1\n"	\
@@ -27,7 +27,7 @@
 
 #else /* CONFIG_DEBUG_BUGVERBOSE */
 
-#define __EMIT_BUG(x) do {					\
+#define __EMIT_BUG(cond_str, x) do {				\
 	asm_inline volatile(					\
 		"0:	mc	0,0\n"				\
 		".section __bug_table,\"aw\"\n"			\
@@ -42,12 +42,12 @@
 #endif /* CONFIG_DEBUG_BUGVERBOSE */
 
 #define BUG() do {					\
-	__EMIT_BUG(0);					\
+	__EMIT_BUG("", 0);				\
 	unreachable();					\
 } while (0)
 
 #define __WARN_FLAGS(cond_str, flags) do {		\
-	__EMIT_BUG(BUGFLAG_WARNING|(flags));		\
+	__EMIT_BUG(cond_str, BUGFLAG_WARNING|(flags));	\
 } while (0)
 
 #define WARN_ON(x) ({					\
-- 
2.45.2

[PATCH 10/14] bugs/riscv: Pass in 'cond_str' to __BUG_FLAGS()

[Ingo Molnar]

Pass in the condition string from __WARN_FLAGS() to __BUG_FLAGS(),
but don't use it yet.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: linux-riscv@lists.infradead.org
Cc: <linux-arch@vger.kernel.org>
---
 arch/riscv/include/asm/bug.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
index b22ee4d2c882..feaf456d465b 100644
--- a/arch/riscv/include/asm/bug.h
+++ b/arch/riscv/include/asm/bug.h
@@ -50,7 +50,7 @@ typedef u32 bug_insn_t;
 #endif
 
 #ifdef CONFIG_GENERIC_BUG
-#define __BUG_FLAGS(flags)					\
+#define __BUG_FLAGS(cond_str, flags)				\
 do {								\
 	__asm__ __volatile__ (					\
 		"1:\n\t"					\
@@ -66,17 +66,17 @@ do {								\
 		  "i" (sizeof(struct bug_entry)));              \
 } while (0)
 #else /* CONFIG_GENERIC_BUG */
-#define __BUG_FLAGS(flags) do {					\
+#define __BUG_FLAGS(cond_str, flags) do {			\
 	__asm__ __volatile__ ("ebreak\n");			\
 } while (0)
 #endif /* CONFIG_GENERIC_BUG */
 
 #define BUG() do {						\
-	__BUG_FLAGS(0);						\
+	__BUG_FLAGS("", 0);					\
 	unreachable();						\
 } while (0)
 
-#define __WARN_FLAGS(cond_str, flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
+#define __WARN_FLAGS(cond_str, flags) __BUG_FLAGS(cond_str, BUGFLAG_WARNING|(flags))
 
 #define HAVE_ARCH_BUG
 
-- 
2.45.2

[PATCH 11/14] bugs/riscv: Concatenate 'cond_str' with '__FILE__' in __BUG_FLAGS(), to extend WARN_ON/BUG_ON output

[Ingo Molnar]

Extend WARN_ON and BUG_ON style output from:

  WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:8511 sched_init+0x20/0x410

to:

  WARNING: CPU: 0 PID: 0 at [idx < 0 && ptr] kernel/sched/core.c:8511 sched_init+0x20/0x410

Note that the output will be further reorganized later in this series.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: linux-riscv@lists.infradead.org
Cc: <linux-arch@vger.kernel.org>
---
 arch/riscv/include/asm/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
index feaf456d465b..6278523dd2d1 100644
--- a/arch/riscv/include/asm/bug.h
+++ b/arch/riscv/include/asm/bug.h
@@ -61,7 +61,7 @@ do {								\
 			".org 2b + %3\n\t"                      \
 			".popsection"				\
 		:						\
-		: "i" (__FILE__), "i" (__LINE__),		\
+		: "i" (cond_str __FILE__), "i" (__LINE__),	\
 		  "i" (flags),					\
 		  "i" (sizeof(struct bug_entry)));              \
 } while (0)
-- 
2.45.2

[PATCH 12/14] bugs/parisc: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output

[Ingo Molnar]

Extend WARN_ON and BUG_ON style output from:

  WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:8511 sched_init+0x20/0x410

to:

  WARNING: CPU: 0 PID: 0 at [idx < 0 && ptr] kernel/sched/core.c:8511 sched_init+0x20/0x410

Note that the output will be further reorganized later in this series.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: <linux-arch@vger.kernel.org>
---
 arch/parisc/include/asm/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/parisc/include/asm/bug.h b/arch/parisc/include/asm/bug.h
index 1a87cf80ec3c..2d14d6cf21f3 100644
--- a/arch/parisc/include/asm/bug.h
+++ b/arch/parisc/include/asm/bug.h
@@ -61,7 +61,7 @@
 			     "\t.short %1, %2\n"			\
 			     "\t.blockz %3-2*4-2*2\n"			\
 			     "\t.popsection"				\
-			     : : "i" (__FILE__), "i" (__LINE__),	\
+			     : : "i" (cond_str __FILE__), "i" (__LINE__), \
 			     "i" (BUGFLAG_WARNING|(flags)),		\
 			     "i" (sizeof(struct bug_entry)) );		\
 	} while(0)
-- 
2.45.2

[PATCH 13/14] bugs/sh: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output

[Ingo Molnar]

Extend WARN_ON and BUG_ON style output from:

  WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:8511 sched_init+0x20/0x410

to:

  WARNING: CPU: 0 PID: 0 at [idx < 0 && ptr] kernel/sched/core.c:8511 sched_init+0x20/0x410

Note that the output will be further reorganized later in this series.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: linux-sh@vger.kernel.org
Cc: <linux-arch@vger.kernel.org>
---
 arch/sh/include/asm/bug.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
index 834c621ab249..20d5220bf452 100644
--- a/arch/sh/include/asm/bug.h
+++ b/arch/sh/include/asm/bug.h
@@ -59,7 +59,7 @@ do {							\
 		 _EMIT_BUG_ENTRY			\
 		 :					\
 		 : "n" (TRAPA_BUG_OPCODE),		\
-		   "i" (__FILE__),			\
+		   "i" (cond_str __FILE__),		\
 		   "i" (__LINE__),			\
 		   "i" (BUGFLAG_WARNING|(flags)),	\
 		   "i" (sizeof(struct bug_entry)));	\
-- 
2.45.2

[PATCH 14/14] bugs/core: Reorganize fields in the first line of WARNING output, add ->comm[] output

[Ingo Molnar]

With the introduction of the condition string as part of the 'file'
string output of kernel warnings, the first line has become a bit
harder to read:

   WARNING: CPU: 0 PID: 0 at [ptr == 0 && 1] kernel/sched/core.c:8511 sched_init+0x20/0x410

Re-order the fields by importance (higher to lower), make the 'at' meaningful
again, and add '->comm[]' output which is often more valuable than a PID.

Also, remove the 'PID' prefix - in combination with comm it's clear what it is.

These changes make the output only slightly longer:

   WARNING: [ptr == 0 && 1] kernel/sched/core.c:8511 at sched_init+0x20/0x410 CPU#0: swapper/0

While adding more information and making it better organized.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <linux-arch@vger.kernel.org>
---
 kernel/panic.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index d8635d5cecb2..e57a61faa05f 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -724,13 +724,15 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 
 	disable_trace_on_warning();
 
-	if (file)
-		pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
-			raw_smp_processor_id(), current->pid, file, line,
-			caller);
-	else
-		pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
-			raw_smp_processor_id(), current->pid, caller);
+	if (file) {
+		pr_warn("WARNING: %s:%d at %pS, CPU#%d: %s/%d\n",
+			file, line, caller,
+			raw_smp_processor_id(), current->comm, current->pid);
+	} else {
+		pr_warn("WARNING: at %pS, CPU#%d: %s/%d\n",
+			caller,
+			raw_smp_processor_id(), current->comm, current->pid);
+	}
 
 #pragma GCC diagnostic push
 #ifndef __clang__
-- 
2.45.2

Re: [PATCH 13/14] bugs/sh: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output

[Linus Torvalds]

On Thu, 27 Mar 2025 at 03:30, Ingo Molnar <mingo@kernel.org> wrote:
>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> Cc: linux-sh@vger.kernel.org
> Cc: <linux-arch@vger.kernel.org>

You say that, but I don't see that in the actual email, which only
went to lkml...

So the sh maintainers (and riscv and s390 etc: same issue with those
emails) probably never saw this.

The patches look fine to me, fwiw.

           Linus

Re: [PATCH 13/14] bugs/sh: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output

[Ingo Molnar]

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Thu, 27 Mar 2025 at 03:30, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> > Cc: Rich Felker <dalias@libc.org>
> > Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> > Cc: linux-sh@vger.kernel.org
> > Cc: <linux-arch@vger.kernel.org>
> 
> You say that, but I don't see that in the actual email, which only
> went to lkml...

Indeed, usually I rely on the tip-bot picking up Cc: lines, but here it 
would be useful to have earlier Cc:s and my script had, for some stupid 
reason:

  --suppress-cc=all

... which certainly suppressed the Cc: lines :-/

Will take a careful look at a --dry-run output next time around and 
make sure the --signed-off-by-cc auto-cc logic picks up all the Cc: 
lines in the individual commits.

> So the sh maintainers (and riscv and s390 etc: same issue with those 
> emails) probably never saw this.

Yeah, will iterate it once more just to make sure.

Thanks,

	Ingo

Re: [PATCH 13/14] bugs/sh: Concatenate 'cond_str' with '__FILE__' in __WARN_FLAGS(), to extend WARN_ON/BUG_ON output

[Ingo Molnar]

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> The patches look fine to me, fwiw.

So I've changed the series slightly to add a new Kconfig option to 
trigger these extra strings:

	CONFIG_DEBUG_BUGVERBOSE_DETAILED=y

Disabled by default.

This should address concerns over the +100K kernel size increase that 
some have raised.

I'll send out a -v2 series, which should have the Cc: problems fixed as 
well, so that all architecture people see it too.

Thanks,

	Ingo