* [PATCH 10/15] bugs/s390: Pass in 'cond_str' to __EMIT_BUG() [not found] <20250515124644.2958810-1-mingo@kernel.org> @ 2025-05-15 12:46 ` Ingo Molnar 2025-05-20 13:39 ` Heiko Carstens 0 siblings, 1 reply; 4+ messages in thread From: Ingo Molnar @ 2025-05-15 12:46 UTC (permalink / raw) To: linux-kernel Cc: Ingo Molnar, Linus Torvalds, Peter Zijlstra, linux-arch, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Christian Borntraeger, Sven Schnelle, linux-s390 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 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 10/15] bugs/s390: Pass in 'cond_str' to __EMIT_BUG() 2025-05-15 12:46 ` [PATCH 10/15] bugs/s390: Pass in 'cond_str' to __EMIT_BUG() Ingo Molnar @ 2025-05-20 13:39 ` Heiko Carstens 2025-06-09 8:27 ` [PATCH 16/15] bugs/s390: Use " Ingo Molnar 0 siblings, 1 reply; 4+ messages in thread From: Heiko Carstens @ 2025-05-20 13:39 UTC (permalink / raw) To: Ingo Molnar Cc: linux-kernel, Linus Torvalds, Peter Zijlstra, linux-arch, Vasily Gorbik, Alexander Gordeev, Christian Borntraeger, Sven Schnelle, linux-s390 On Thu, May 15, 2025 at 02:46:39PM +0200, Ingo Molnar wrote: > 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. Could you provide your change which didn't work? I cannot see how anything would overflow. Trying the below on top of your series seems to work like expected. In order to keep things easy this drops the mergeable section trick and results in a small increase of the rodata section, but I doubt that would explain what you have seen. Also allyesconfig builds without errors. diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h index 30f8785a01f5..837bfbde0c51 100644 --- a/arch/s390/include/asm/bug.h +++ b/arch/s390/include/asm/bug.h @@ -11,16 +11,14 @@ #define __EMIT_BUG(cond_str, 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,\"aw\"\n" \ - "2: .long 0b-.\n" \ - " .long 1b-.\n" \ - " .short %0,%1\n" \ - " .org 2b+%2\n" \ + "1: .long 0b-.\n" \ + " .long %0-.\n" \ + " .short %1,%2\n" \ + " .org 1b+%3\n" \ ".previous\n" \ - : : "i" (__LINE__), \ + : : "i" (WARN_CONDITION_STR(cond_str) __FILE__),\ + "i" (__LINE__), \ "i" (x), \ "i" (sizeof(struct bug_entry))); \ } while (0) ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 16/15] bugs/s390: Use in 'cond_str' to __EMIT_BUG() 2025-05-20 13:39 ` Heiko Carstens @ 2025-06-09 8:27 ` Ingo Molnar 2025-06-09 15:56 ` Heiko Carstens 0 siblings, 1 reply; 4+ messages in thread From: Ingo Molnar @ 2025-06-09 8:27 UTC (permalink / raw) To: Heiko Carstens Cc: linux-kernel, Linus Torvalds, Peter Zijlstra, linux-arch, Vasily Gorbik, Alexander Gordeev, Christian Borntraeger, Sven Schnelle, linux-s390 * Heiko Carstens <hca@linux.ibm.com> wrote: > On Thu, May 15, 2025 at 02:46:39PM +0200, Ingo Molnar wrote: > > 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. > > Could you provide your change which didn't work? > > I cannot see how anything would overflow. Trying the below on top of > your series seems to work like expected. > > In order to keep things easy this drops the mergeable section trick > and results in a small increase of the rodata section, but I doubt > that would explain what you have seen. > > Also allyesconfig builds without errors. > > diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h > index 30f8785a01f5..837bfbde0c51 100644 > --- a/arch/s390/include/asm/bug.h > +++ b/arch/s390/include/asm/bug.h > @@ -11,16 +11,14 @@ > #define __EMIT_BUG(cond_str, 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,\"aw\"\n" \ > - "2: .long 0b-.\n" \ > - " .long 1b-.\n" \ > - " .short %0,%1\n" \ > - " .org 2b+%2\n" \ > + "1: .long 0b-.\n" \ > + " .long %0-.\n" \ > + " .short %1,%2\n" \ > + " .org 1b+%3\n" \ > ".previous\n" \ > - : : "i" (__LINE__), \ > + : : "i" (WARN_CONDITION_STR(cond_str) __FILE__),\ > + "i" (__LINE__), \ > "i" (x), \ > "i" (sizeof(struct bug_entry))); \ > } while (0) So I'm not sure what happened: I tried to reproduce what I did originally, but my naive patch ran into assembler build errors when a WARN_ON() macro tried to use the '%' C operator, such as fs/crypto/crypto.c:123: include/linux/compiler_types.h:497:20: error: invalid 'asm': invalid %-code arch/s390/include/asm/bug.h:12:2: note: in expansion of macro 'asm_inline' arch/s390/include/asm/bug.h:50:2: note: in expansion of macro '__EMIT_BUG' include/asm-generic/bug.h:119:3: note: in expansion of macro '__WARN_FLAGS' fs/crypto/crypto.c:123:6: note: in expansion of macro 'WARN_ON_ONCE' Which corresponds to: if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0)) return -EINVAL; I'm quite sure I never saw these build errors - I saw linker errors related to the u16 overflow I documented in the changelog. (Note to self: copy & paste more of the build error context next time around.) Your version doesn't have that build problem, so I picked it up with the changelog below and your Signed-off-by. Does that look good to you? Thanks, Ingo ===================================> From 7128294ca8b997efb1d85c7405c8c6e9af1a170d Mon Sep 17 00:00:00 2001 From: Heiko Carstens <hca@linux.ibm.com> Date: Tue, 20 May 2025 15:39:27 +0200 Subject: [PATCH] bugs/s390: Use 'cond_str' in __EMIT_BUG() In order to keep things easy this drops the mergeable section trick and results in a small increase of the rodata section. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-arch@vger.kernel.org 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 Link: https://lore.kernel.org/r/20250520133927.7932C19-hca@linux.ibm.com --- arch/s390/include/asm/bug.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h index 30f8785a01f5..837bfbde0c51 100644 --- a/arch/s390/include/asm/bug.h +++ b/arch/s390/include/asm/bug.h @@ -11,16 +11,14 @@ #define __EMIT_BUG(cond_str, 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,\"aw\"\n" \ - "2: .long 0b-.\n" \ - " .long 1b-.\n" \ - " .short %0,%1\n" \ - " .org 2b+%2\n" \ + "1: .long 0b-.\n" \ + " .long %0-.\n" \ + " .short %1,%2\n" \ + " .org 1b+%3\n" \ ".previous\n" \ - : : "i" (__LINE__), \ + : : "i" (WARN_CONDITION_STR(cond_str) __FILE__),\ + "i" (__LINE__), \ "i" (x), \ "i" (sizeof(struct bug_entry))); \ } while (0) ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 16/15] bugs/s390: Use in 'cond_str' to __EMIT_BUG() 2025-06-09 8:27 ` [PATCH 16/15] bugs/s390: Use " Ingo Molnar @ 2025-06-09 15:56 ` Heiko Carstens 0 siblings, 0 replies; 4+ messages in thread From: Heiko Carstens @ 2025-06-09 15:56 UTC (permalink / raw) To: Ingo Molnar Cc: linux-kernel, Linus Torvalds, Peter Zijlstra, linux-arch, Vasily Gorbik, Alexander Gordeev, Christian Borntraeger, Sven Schnelle, linux-s390 On Mon, Jun 09, 2025 at 10:27:44AM +0200, Ingo Molnar wrote: > So I'm not sure what happened: I tried to reproduce what I did > originally, but my naive patch ran into assembler build errors when a > WARN_ON() macro tried to use the '%' C operator, such as > fs/crypto/crypto.c:123: > > include/linux/compiler_types.h:497:20: error: invalid 'asm': invalid %-code > arch/s390/include/asm/bug.h:12:2: note: in expansion of macro 'asm_inline' > arch/s390/include/asm/bug.h:50:2: note: in expansion of macro '__EMIT_BUG' > include/asm-generic/bug.h:119:3: note: in expansion of macro '__WARN_FLAGS' > fs/crypto/crypto.c:123:6: note: in expansion of macro 'WARN_ON_ONCE' > > Which corresponds to: > > if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0)) > return -EINVAL; > > I'm quite sure I never saw these build errors - I saw linker errors > related to the u16 overflow I documented in the changelog. (Note to > self: copy & paste more of the build error context next time around.) > > Your version doesn't have that build problem, so I picked it up with > the changelog below and your Signed-off-by. Does that look good to you? Yes, fine with me. ^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-05-15 12:46 ` [PATCH 10/15] bugs/s390: Pass in 'cond_str' to __EMIT_BUG() Ingo Molnar
2025-05-20 13:39 ` Heiko Carstens
2025-06-09 8:27 ` [PATCH 16/15] bugs/s390: Use " Ingo Molnar
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