Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Veronika Kabatova]

Hi,

for a while we've been seen the following error when compiling
the mainline kernel with gcc 11.2 and binutils 2.37:

00:02:32 Cannot find symbol for section 11: .text.unlikely.
00:02:32 kernel/kexec_file.o: failed
00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
00:02:32 make[2]: *** Waiting for unfinished jobs....

The error only happens with ppc64le. I've tested this with cross
compilation, but the only reference to the error I found suggests
the same happens with the native compiles as well:

https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98

In case it matters, the config used is the Fedora config with
kselftest options enabled, which you can grab from

https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config


I've reached out to the Fedora compiler folks and Nick Clifton
suggested this is a problem with the kernel:

    This message comes from the recordmcount tool, which is part of the kernel
    sources:

    linux/scripts/recordmcount.[ch]

    It appears to be triggered when a compiler update causes code to be
    rearranged. The problem has been reported before in various forums,
    but in particular I found this reference:

    https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd@kernel.org/

    The point of which to me at least is that this is a kernel issue rather than
    a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
    which need to be moved elsewhere.


Is this something that is indeed an issue that should be fixed in the
kernel, or should I reach out to someone else? I'm happy to test any
patches provided.

Thank you,
Veronika


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Baoquan He]

On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
> Hi,
> 
> for a while we've been seen the following error when compiling
> the mainline kernel with gcc 11.2 and binutils 2.37:
> 
> 00:02:32 Cannot find symbol for section 11: .text.unlikely.
> 00:02:32 kernel/kexec_file.o: failed
> 00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
> 00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
> 00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
> 00:02:32 make[2]: *** Waiting for unfinished jobs....
> 
> The error only happens with ppc64le. I've tested this with cross
> compilation, but the only reference to the error I found suggests
> the same happens with the native compiles as well:
> 
> https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
> 
> In case it matters, the config used is the Fedora config with
> kselftest options enabled, which you can grab from
> 
> https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
> 
> 
> I've reached out to the Fedora compiler folks and Nick Clifton
> suggested this is a problem with the kernel:
> 
>     This message comes from the recordmcount tool, which is part of the kernel
>     sources:
> 
>     linux/scripts/recordmcount.[ch]
> 
>     It appears to be triggered when a compiler update causes code to be
>     rearranged. The problem has been reported before in various forums,
>     but in particular I found this reference:
> 
>     https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd@kernel.org/
> 
>     The point of which to me at least is that this is a kernel issue rather than
>     a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
>     which need to be moved elsewhere.

It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
is __weak, but not implemented in any ARCH. If true, this has been
pointed out by Eric in one patch thread from Coiby.

[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
http://lkml.kernel.org/r/20211018083137.338757-2-coxu@redhat.com

Maybe Coiby can fetch above config file and run the test to check.

Thanks
Baoquan


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Coiby Xu]

[-- Attachment #1: Type: text/plain, Size: 2821 bytes --]

On Wed, Nov 24, 2021 at 09:47:43PM +0800, Baoquan He wrote:
>On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
>> Hi,
>>
>> for a while we've been seen the following error when compiling
>> the mainline kernel with gcc 11.2 and binutils 2.37:
>>
>> 00:02:32 Cannot find symbol for section 11: .text.unlikely.
>> 00:02:32 kernel/kexec_file.o: failed
>> 00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
>> 00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
>> 00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
>> 00:02:32 make[2]: *** Waiting for unfinished jobs....
>>
>> The error only happens with ppc64le. I've tested this with cross
>> compilation, but the only reference to the error I found suggests
>> the same happens with the native compiles as well:
>>
>> https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
>>
>> In case it matters, the config used is the Fedora config with
>> kselftest options enabled, which you can grab from
>>
>> https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
>>
>>
>> I've reached out to the Fedora compiler folks and Nick Clifton
>> suggested this is a problem with the kernel:
>>
>>     This message comes from the recordmcount tool, which is part of the kernel
>>     sources:
>>
>>     linux/scripts/recordmcount.[ch]
>>
>>     It appears to be triggered when a compiler update causes code to be
>>     rearranged. The problem has been reported before in various forums,
>>     but in particular I found this reference:
>>
>>     https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd@kernel.org/
>>
>>     The point of which to me at least is that this is a kernel issue rather than
>>     a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
>>     which need to be moved elsewhere.
>
>It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
>is __weak, but not implemented in any ARCH. If true, this has been
>pointed out by Eric in one patch thread from Coiby.
>
>[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
>http://lkml.kernel.org/r/20211018083137.338757-2-coxu@redhat.com
>
>Maybe Coiby can fetch above config file and run the test to check.

"[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig" alone
would fix the error. If I turn arch_kexec_apply_relocations{_add,} into
static function, the error would be gone. As attached is the patch would
make this error disappear. 

However, s390 and x86 have its own implementation of
arch_kexec_apply_relocations_add. This makes it looks like to be gcc's
issue.


>
>Thanks
>Baoquan
>

-- 
Best regards,
Coiby

[-- Attachment #2: 0001-fix-error-ppc64le-Cannot-find-symbol-for-section-11-.patch --]
[-- Type: text/plain, Size: 4069 bytes --]

From 49e0333f5a0743cdcc99777218524d6a6cd5ec34 Mon Sep 17 00:00:00 2001
From: Coiby Xu <coxu@redhat.com>
Date: Mon, 18 Oct 2021 15:52:46 +0800
Subject: [PATCH] fix error "ppc64le: Cannot find symbol for section 11:
 .text.unlikely."

---
 include/linux/kexec.h | 13 -------------
 kernel/kexec_file.c   | 40 ++++++++++++++++------------------------
 2 files changed, 16 insertions(+), 37 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 0c994ae37..1476470a1 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -186,20 +186,7 @@ void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name);
 /* Architectures may override the below functions */
 int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
 				  unsigned long buf_len);
-void *arch_kexec_kernel_image_load(struct kimage *image);
-int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
-				     Elf_Shdr *section,
-				     const Elf_Shdr *relsec,
-				     const Elf_Shdr *symtab);
-int arch_kexec_apply_relocations(struct purgatory_info *pi,
-				 Elf_Shdr *section,
-				 const Elf_Shdr *relsec,
-				 const Elf_Shdr *symtab);
 int arch_kimage_file_post_load_cleanup(struct kimage *image);
-#ifdef CONFIG_KEXEC_SIG
-int arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
-				 unsigned long buf_len);
-#endif
 int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
 
 extern int kexec_add_buffer(struct kexec_buf *kbuf);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 8347fc158..e0afe36d3 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -71,7 +71,7 @@ static void *kexec_image_load_default(struct kimage *image)
 				 image->cmdline_buf_len);
 }
 
-void * __weak arch_kexec_kernel_image_load(struct kimage *image)
+static void * arch_kexec_kernel_image_load(struct kimage *image)
 {
 	return kexec_image_load_default(image);
 }
@@ -89,25 +89,6 @@ int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
 	return kexec_image_post_load_cleanup_default(image);
 }
 
-#ifdef CONFIG_KEXEC_SIG
-static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
-					  unsigned long buf_len)
-{
-	if (!image->fops || !image->fops->verify_sig) {
-		pr_debug("kernel loader does not support signature verification.\n");
-		return -EKEYREJECTED;
-	}
-
-	return image->fops->verify_sig(buf, buf_len);
-}
-
-int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
-					unsigned long buf_len)
-{
-	return kexec_image_verify_sig_default(image, buf, buf_len);
-}
-#endif
-
 /*
  * arch_kexec_apply_relocations_add - apply relocations of type RELA
  * @pi:		Purgatory to be relocated.
@@ -117,7 +98,7 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
  *
  * Return: 0 on success, negative errno on error.
  */
-int __weak
+static int
 arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
 				 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 {
@@ -134,7 +115,7 @@ arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
  *
  * Return: 0 on success, negative errno on error.
  */
-int __weak
+static int
 arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
 			     const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 {
@@ -184,13 +165,24 @@ void kimage_file_post_load_cleanup(struct kimage *image)
 }
 
 #ifdef CONFIG_KEXEC_SIG
+static int kexec_image_verify_sig(struct kimage *image, void *buf,
+		unsigned long buf_len)
+{
+	if (!image->fops || !image->fops->verify_sig) {
+		pr_debug("kernel loader does not support signature verification.\n");
+		return -EKEYREJECTED;
+	}
+
+	return image->fops->verify_sig(buf, buf_len);
+}
+
 static int
 kimage_validate_signature(struct kimage *image)
 {
 	int ret;
 
-	ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
-					   image->kernel_buf_len);
+	ret = kexec_image_verify_sig(image, image->kernel_buf,
+			image->kernel_buf_len);
 	if (ret) {
 
 		if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
-- 
2.33.1


[-- Attachment #3: Type: text/plain, Size: 143 bytes --]

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Coiby Xu]

On Wed, Dec 01, 2021 at 10:19:26AM +0800, Coiby Xu wrote:
>On Wed, Nov 24, 2021 at 09:47:43PM +0800, Baoquan He wrote:
>>On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
>>>Hi,
>>>
>>>for a while we've been seen the following error when compiling
>>>the mainline kernel with gcc 11.2 and binutils 2.37:
>>>
>>>00:02:32 Cannot find symbol for section 11: .text.unlikely.
>>>00:02:32 kernel/kexec_file.o: failed
>>>00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
>>>00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
>>>00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
>>>00:02:32 make[2]: *** Waiting for unfinished jobs....
>>>
>>>The error only happens with ppc64le. I've tested this with cross
>>>compilation, but the only reference to the error I found suggests
>>>the same happens with the native compiles as well:
>>>
>>>https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
>>>
>>>In case it matters, the config used is the Fedora config with
>>>kselftest options enabled, which you can grab from
>>>
>>>https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
>>>
>>>
>>>I've reached out to the Fedora compiler folks and Nick Clifton
>>>suggested this is a problem with the kernel:
>>>
>>>    This message comes from the recordmcount tool, which is part of the kernel
>>>    sources:
>>>
>>>    linux/scripts/recordmcount.[ch]
>>>
>>>    It appears to be triggered when a compiler update causes code to be
>>>    rearranged. The problem has been reported before in various forums,
>>>    but in particular I found this reference:
>>>
>>>    https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd@kernel.org/
>>>
>>>    The point of which to me at least is that this is a kernel issue rather than
>>>    a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
>>>    which need to be moved elsewhere.
>>
>>It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
>>is __weak, but not implemented in any ARCH. If true, this has been
>>pointed out by Eric in one patch thread from Coiby.
>>
>>[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
>>http://lkml.kernel.org/r/20211018083137.338757-2-coxu@redhat.com
>>
>>Maybe Coiby can fetch above config file and run the test to check.
>
>"[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig" alone
>would fix the error. If I turn arch_kexec_apply_relocations{_add,} into
  ^^^^^
  wouldn't 

Sorry I made a typo.

>static function, the error would be gone. As attached is the patch would
>make this error disappear.
>
>However, s390 and x86 have its own implementation of
>arch_kexec_apply_relocations_add. This makes it looks like to be gcc's
>issue.
>
>
>>
>>Thanks
>>Baoquan
>>
>
>-- 
>Best regards,
>Coiby

From 49e0333f5a0743cdcc99777218524d6a6cd5ec34 Mon Sep 17 00:00:00 2001
>From: Coiby Xu <coxu@redhat.com>
>Date: Mon, 18 Oct 2021 15:52:46 +0800
>Subject: [PATCH] fix error "ppc64le: Cannot find symbol for section 11:
> .text.unlikely."
>
>---
> include/linux/kexec.h | 13 -------------
> kernel/kexec_file.c   | 40 ++++++++++++++++------------------------
> 2 files changed, 16 insertions(+), 37 deletions(-)
>
>diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>index 0c994ae37..1476470a1 100644
>--- a/include/linux/kexec.h
>+++ b/include/linux/kexec.h
>@@ -186,20 +186,7 @@ void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name);
> /* Architectures may override the below functions */
> int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> 				  unsigned long buf_len);
>-void *arch_kexec_kernel_image_load(struct kimage *image);
>-int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
>-				     Elf_Shdr *section,
>-				     const Elf_Shdr *relsec,
>-				     const Elf_Shdr *symtab);
>-int arch_kexec_apply_relocations(struct purgatory_info *pi,
>-				 Elf_Shdr *section,
>-				 const Elf_Shdr *relsec,
>-				 const Elf_Shdr *symtab);
> int arch_kimage_file_post_load_cleanup(struct kimage *image);
>-#ifdef CONFIG_KEXEC_SIG
>-int arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
>-				 unsigned long buf_len);
>-#endif
> int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
>
> extern int kexec_add_buffer(struct kexec_buf *kbuf);
>diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
>index 8347fc158..e0afe36d3 100644
>--- a/kernel/kexec_file.c
>+++ b/kernel/kexec_file.c
>@@ -71,7 +71,7 @@ static void *kexec_image_load_default(struct kimage *image)
> 				 image->cmdline_buf_len);
> }
>
>-void * __weak arch_kexec_kernel_image_load(struct kimage *image)
>+static void * arch_kexec_kernel_image_load(struct kimage *image)
> {
> 	return kexec_image_load_default(image);
> }
>@@ -89,25 +89,6 @@ int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
> 	return kexec_image_post_load_cleanup_default(image);
> }
>
>-#ifdef CONFIG_KEXEC_SIG
>-static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
>-					  unsigned long buf_len)
>-{
>-	if (!image->fops || !image->fops->verify_sig) {
>-		pr_debug("kernel loader does not support signature verification.\n");
>-		return -EKEYREJECTED;
>-	}
>-
>-	return image->fops->verify_sig(buf, buf_len);
>-}
>-
>-int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
>-					unsigned long buf_len)
>-{
>-	return kexec_image_verify_sig_default(image, buf, buf_len);
>-}
>-#endif
>-
> /*
>  * arch_kexec_apply_relocations_add - apply relocations of type RELA
>  * @pi:		Purgatory to be relocated.
>@@ -117,7 +98,7 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
>  *
>  * Return: 0 on success, negative errno on error.
>  */
>-int __weak
>+static int
> arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
> 				 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
> {
>@@ -134,7 +115,7 @@ arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
>  *
>  * Return: 0 on success, negative errno on error.
>  */
>-int __weak
>+static int
> arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
> 			     const Elf_Shdr *relsec, const Elf_Shdr *symtab)
> {
>@@ -184,13 +165,24 @@ void kimage_file_post_load_cleanup(struct kimage *image)
> }
>
> #ifdef CONFIG_KEXEC_SIG
>+static int kexec_image_verify_sig(struct kimage *image, void *buf,
>+		unsigned long buf_len)
>+{
>+	if (!image->fops || !image->fops->verify_sig) {
>+		pr_debug("kernel loader does not support signature verification.\n");
>+		return -EKEYREJECTED;
>+	}
>+
>+	return image->fops->verify_sig(buf, buf_len);
>+}
>+
> static int
> kimage_validate_signature(struct kimage *image)
> {
> 	int ret;
>
>-	ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
>-					   image->kernel_buf_len);
>+	ret = kexec_image_verify_sig(image, image->kernel_buf,
>+			image->kernel_buf_len);
> 	if (ret) {
>
> 		if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
>-- 
>2.33.1
>


-- 
Best regards,
Coiby


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Veronika Kabatova]

On Wed, Dec 1, 2021 at 3:20 AM Coiby Xu <coxu@redhat.com> wrote:
>
> On Wed, Nov 24, 2021 at 09:47:43PM +0800, Baoquan He wrote:
> >On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
> >> Hi,
> >>
> >> for a while we've been seen the following error when compiling
> >> the mainline kernel with gcc 11.2 and binutils 2.37:
> >>
> >> 00:02:32 Cannot find symbol for section 11: .text.unlikely.
> >> 00:02:32 kernel/kexec_file.o: failed
> >> 00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
> >> 00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
> >> 00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
> >> 00:02:32 make[2]: *** Waiting for unfinished jobs....
> >>
> >> The error only happens with ppc64le. I've tested this with cross
> >> compilation, but the only reference to the error I found suggests
> >> the same happens with the native compiles as well:
> >>
> >> https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
> >>
> >> In case it matters, the config used is the Fedora config with
> >> kselftest options enabled, which you can grab from
> >>
> >> https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
> >>
> >>
> >> I've reached out to the Fedora compiler folks and Nick Clifton
> >> suggested this is a problem with the kernel:
> >>
> >>     This message comes from the recordmcount tool, which is part of the kernel
> >>     sources:
> >>
> >>     linux/scripts/recordmcount.[ch]
> >>
> >>     It appears to be triggered when a compiler update causes code to be
> >>     rearranged. The problem has been reported before in various forums,
> >>     but in particular I found this reference:
> >>
> >>     https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd@kernel.org/
> >>
> >>     The point of which to me at least is that this is a kernel issue rather than
> >>     a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
> >>     which need to be moved elsewhere.
> >
> >It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
> >is __weak, but not implemented in any ARCH. If true, this has been
> >pointed out by Eric in one patch thread from Coiby.
> >
> >[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
> >http://lkml.kernel.org/r/20211018083137.338757-2-coxu@redhat.com
> >
> >Maybe Coiby can fetch above config file and run the test to check.
>
> "[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig" alone
> would fix the error. If I turn arch_kexec_apply_relocations{_add,} into
> static function, the error would be gone. As attached is the patch would
> make this error disappear.
>

Thank you! I can confirm the attached patch fixes the problem.


Veronika

> However, s390 and x86 have its own implementation of
> arch_kexec_apply_relocations_add. This makes it looks like to be gcc's
> issue.
>
>
> >
> >Thanks
> >Baoquan
> >
>
> --
> Best regards,
> Coiby


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Coiby Xu]

On Fri, Dec 03, 2021 at 04:54:19PM +0100, Veronika Kabatova wrote:
>On Wed, Dec 1, 2021 at 3:20 AM Coiby Xu <coxu@redhat.com> wrote:
>>
>> On Wed, Nov 24, 2021 at 09:47:43PM +0800, Baoquan He wrote:
>> >On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
>> >> Hi,
>> >>
>> >> for a while we've been seen the following error when compiling
>> >> the mainline kernel with gcc 11.2 and binutils 2.37:
>> >>
>> >> 00:02:32 Cannot find symbol for section 11: .text.unlikely.
>> >> 00:02:32 kernel/kexec_file.o: failed
>> >> 00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
>> >> 00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
>> >> 00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
>> >> 00:02:32 make[2]: *** Waiting for unfinished jobs....
>> >>
>> >> The error only happens with ppc64le. I've tested this with cross
>> >> compilation, but the only reference to the error I found suggests
>> >> the same happens with the native compiles as well:
>> >>
>> >> https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
>> >>
>> >> In case it matters, the config used is the Fedora config with
>> >> kselftest options enabled, which you can grab from
>> >>
>> >> https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
>> >>
>> >>
>> >> I've reached out to the Fedora compiler folks and Nick Clifton
>> >> suggested this is a problem with the kernel:
>> >>
>> >>     This message comes from the recordmcount tool, which is part of the kernel
>> >>     sources:
>> >>
>> >>     linux/scripts/recordmcount.[ch]
>> >>
>> >>     It appears to be triggered when a compiler update causes code to be
>> >>     rearranged. The problem has been reported before in various forums,
>> >>     but in particular I found this reference:
>> >>
>> >>     https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd at kernel.org/
>> >>
>> >>     The point of which to me at least is that this is a kernel issue rather than
>> >>     a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
>> >>     which need to be moved elsewhere.
>> >
>> >It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
>> >is __weak, but not implemented in any ARCH. If true, this has been
>> >pointed out by Eric in one patch thread from Coiby.
>> >
>> >[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
>> >http://lkml.kernel.org/r/20211018083137.338757-2-coxu at redhat.com
>> >
>> >Maybe Coiby can fetch above config file and run the test to check.
>>
>> "[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig" alone
>> would fix the error. If I turn arch_kexec_apply_relocations{_add,} into

Sorry I meant "alone won't fix the error".

>> static function, the error would be gone. As attached is the patch would
>> make this error disappear.
>>
>
>Thank you! I can confirm the attached patch fixes the problem.
>
>
>Veronika
>
>> However, s390 and x86 have its own implementation of
>> arch_kexec_apply_relocations_add. This makes it looks like to be gcc's
>> issue.

Based on the above point and further investigation, I think the root cause is
find_secsym_ndx in linux/scripts/recordmcount.h,
  /*
   * Find a symbol in the given section, to be used as the base for relocating
   * the table of offsets of calls to mcount.  A local or global symbol suffices,
   * but avoid a Weak symbol because it may be overridden; the change in value
   * would invalidate the relocations of the offsets of the calls to mcount.
   * Often the found symbol will be the unnamed local symbol generated by
   * GNU 'as' for the start of each section.  For example:
   *    Num:    Value  Size Type    Bind   Vis      Ndx Name
   *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
   */
  static int find_secsym_ndx(unsigned const txtndx,
  				char const *const txtname,
  				uint_t *const recvalp,
  				unsigned int *sym_index,
  				Elf_Shdr const *const symhdr,
  				Elf32_Word const *symtab,
  				Elf32_Word const *symtab_shndx,
  				Elf_Ehdr const *const ehdr)
  {
         ...
		if (txtndx == get_symindex(symp, symtab, symtab_shndx)
			/* avoid STB_WEAK */

	 fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
		txtndx, txtname);

This function prints the above warning after failing to find
arch_kexec_kernel_verify_sig or arch_kexec_apply_relocations{_add,} in
section 11: .text.unlikely. because it ignores the weak symbol and ppc64le
doesn't its arch implementations of these functions. I'll see if I can fix
it in linux/scripts/recordmcount.h.

>>
>>
>> >
>> >Thanks
>> >Baoquan
>> >
>>
>> --
>> Best regards,
>> Coiby
>

-- 
Best regards,
Coiby

Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Coiby Xu]

On Fri, Feb 25, 2022 at 11:46:41AM +0800, Coiby Xu wrote:
>On Fri, Dec 03, 2021 at 04:54:19PM +0100, Veronika Kabatova wrote:
>>On Wed, Dec 1, 2021 at 3:20 AM Coiby Xu <coxu@redhat.com> wrote:
>>>
>>>On Wed, Nov 24, 2021 at 09:47:43PM +0800, Baoquan He wrote:
>>>>On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
>>>>> Hi,
>>>>>
>>>>> for a while we've been seen the following error when compiling
>>>>> the mainline kernel with gcc 11.2 and binutils 2.37:
>>>>>
>>>>> 00:02:32 Cannot find symbol for section 11: .text.unlikely.
>>>>> 00:02:32 kernel/kexec_file.o: failed
>>>>> 00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
>>>>> 00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
>>>>> 00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
>>>>> 00:02:32 make[2]: *** Waiting for unfinished jobs....
>>>>>
>>>>> The error only happens with ppc64le. I've tested this with cross
>>>>> compilation, but the only reference to the error I found suggests
>>>>> the same happens with the native compiles as well:
>>>>>
>>>>> https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
>>>>>
>>>>> In case it matters, the config used is the Fedora config with
>>>>> kselftest options enabled, which you can grab from
>>>>>
>>>>> https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
>>>>>
>>>>>
>>>>> I've reached out to the Fedora compiler folks and Nick Clifton
>>>>> suggested this is a problem with the kernel:
>>>>>
>>>>>     This message comes from the recordmcount tool, which is part of the kernel
>>>>>     sources:
>>>>>
>>>>>     linux/scripts/recordmcount.[ch]
>>>>>
>>>>>     It appears to be triggered when a compiler update causes code to be
>>>>>     rearranged. The problem has been reported before in various forums,
>>>>>     but in particular I found this reference:
>>>>>
>>>>>     https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd at kernel.org/
>>>>>
>>>>>     The point of which to me at least is that this is a kernel issue rather than
>>>>>     a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
>>>>>     which need to be moved elsewhere.
>>>>
>>>>It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
>>>>is __weak, but not implemented in any ARCH. If true, this has been
>>>>pointed out by Eric in one patch thread from Coiby.
>>>>
>>>>[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
>>>>http://lkml.kernel.org/r/20211018083137.338757-2-coxu at redhat.com
>>>>
>>>>Maybe Coiby can fetch above config file and run the test to check.
>>>
>>>"[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig" alone
>>>would fix the error. If I turn arch_kexec_apply_relocations{_add,} into
>
>Sorry I meant "alone won't fix the error".
>
>>>static function, the error would be gone. As attached is the patch would
>>>make this error disappear.
>>>
>>
>>Thank you! I can confirm the attached patch fixes the problem.
>>
>>
>>Veronika
>>
>>>However, s390 and x86 have its own implementation of
>>>arch_kexec_apply_relocations_add. This makes it looks like to be gcc's
>>>issue.
>
>Based on the above point and further investigation, I think the root cause is
>find_secsym_ndx in linux/scripts/recordmcount.h,
> /*
>  * Find a symbol in the given section, to be used as the base for relocating
>  * the table of offsets of calls to mcount.  A local or global symbol suffices,
>  * but avoid a Weak symbol because it may be overridden; the change in value
>  * would invalidate the relocations of the offsets of the calls to mcount.
>  * Often the found symbol will be the unnamed local symbol generated by
>  * GNU 'as' for the start of each section.  For example:
>  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
>  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
>  */
> static int find_secsym_ndx(unsigned const txtndx,
> 				char const *const txtname,
> 				uint_t *const recvalp,
> 				unsigned int *sym_index,
> 				Elf_Shdr const *const symhdr,
> 				Elf32_Word const *symtab,
> 				Elf32_Word const *symtab_shndx,
> 				Elf_Ehdr const *const ehdr)
> {
>        ...
>		if (txtndx == get_symindex(symp, symtab, symtab_shndx)
>			/* avoid STB_WEAK */
>
>	 fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
>		txtndx, txtname);
>
>This function prints the above warning after failing to find
>arch_kexec_kernel_verify_sig or arch_kexec_apply_relocations{_add,} in
>section 11: .text.unlikely. because it ignores the weak symbol and ppc64le
>doesn't its arch implementations of these functions. I'll see if I can fix
>it in linux/scripts/recordmcount.h.

After digging deeper into linux/scripts/recordmcount.h, I think this
issue can be either fixed in the compiler or recordmcount. So I fild two bugs
- gcc: https://bugzilla.redhat.com/show_bug.cgi?id=2059838
- linux/scripts/recordmcount.h: https://bugzilla.redhat.com/show_bug.cgi?id=2059842

>
>>>
>>>
>>>>
>>>>Thanks
>>>>Baoquan
>>>>
>>>
>>>--
>>>Best regards,
>>>Coiby
>>
>
>-- 
>Best regards,
>Coiby

-- 
Best regards,
Coiby

Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Veronika Kabatova]

On Wed, Mar 2, 2022 at 8:50 AM Coiby Xu <coxu@redhat.com> wrote:
>
> On Fri, Feb 25, 2022 at 11:46:41AM +0800, Coiby Xu wrote:
> >On Fri, Dec 03, 2021 at 04:54:19PM +0100, Veronika Kabatova wrote:
> >>On Wed, Dec 1, 2021 at 3:20 AM Coiby Xu <coxu@redhat.com> wrote:
> >>>
> >>>On Wed, Nov 24, 2021 at 09:47:43PM +0800, Baoquan He wrote:
> >>>>On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
> >>>>> Hi,
> >>>>>
> >>>>> for a while we've been seen the following error when compiling
> >>>>> the mainline kernel with gcc 11.2 and binutils 2.37:
> >>>>>
> >>>>> 00:02:32 Cannot find symbol for section 11: .text.unlikely.
> >>>>> 00:02:32 kernel/kexec_file.o: failed
> >>>>> 00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
> >>>>> 00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
> >>>>> 00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
> >>>>> 00:02:32 make[2]: *** Waiting for unfinished jobs....
> >>>>>
> >>>>> The error only happens with ppc64le. I've tested this with cross
> >>>>> compilation, but the only reference to the error I found suggests
> >>>>> the same happens with the native compiles as well:
> >>>>>
> >>>>> https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
> >>>>>
> >>>>> In case it matters, the config used is the Fedora config with
> >>>>> kselftest options enabled, which you can grab from
> >>>>>
> >>>>> https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
> >>>>>
> >>>>>
> >>>>> I've reached out to the Fedora compiler folks and Nick Clifton
> >>>>> suggested this is a problem with the kernel:
> >>>>>
> >>>>>     This message comes from the recordmcount tool, which is part of the kernel
> >>>>>     sources:
> >>>>>
> >>>>>     linux/scripts/recordmcount.[ch]
> >>>>>
> >>>>>     It appears to be triggered when a compiler update causes code to be
> >>>>>     rearranged. The problem has been reported before in various forums,
> >>>>>     but in particular I found this reference:
> >>>>>
> >>>>>     https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd at kernel.org/
> >>>>>
> >>>>>     The point of which to me at least is that this is a kernel issue rather than
> >>>>>     a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
> >>>>>     which need to be moved elsewhere.
> >>>>
> >>>>It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
> >>>>is __weak, but not implemented in any ARCH. If true, this has been
> >>>>pointed out by Eric in one patch thread from Coiby.
> >>>>
> >>>>[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
> >>>>http://lkml.kernel.org/r/20211018083137.338757-2-coxu at redhat.com
> >>>>
> >>>>Maybe Coiby can fetch above config file and run the test to check.
> >>>
> >>>"[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig" alone
> >>>would fix the error. If I turn arch_kexec_apply_relocations{_add,} into
> >
> >Sorry I meant "alone won't fix the error".
> >
> >>>static function, the error would be gone. As attached is the patch would
> >>>make this error disappear.
> >>>
> >>
> >>Thank you! I can confirm the attached patch fixes the problem.
> >>
> >>
> >>Veronika
> >>
> >>>However, s390 and x86 have its own implementation of
> >>>arch_kexec_apply_relocations_add. This makes it looks like to be gcc's
> >>>issue.
> >
> >Based on the above point and further investigation, I think the root cause is
> >find_secsym_ndx in linux/scripts/recordmcount.h,
> > /*
> >  * Find a symbol in the given section, to be used as the base for relocating
> >  * the table of offsets of calls to mcount.  A local or global symbol suffices,
> >  * but avoid a Weak symbol because it may be overridden; the change in value
> >  * would invalidate the relocations of the offsets of the calls to mcount.
> >  * Often the found symbol will be the unnamed local symbol generated by
> >  * GNU 'as' for the start of each section.  For example:
> >  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
> >  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
> >  */
> > static int find_secsym_ndx(unsigned const txtndx,
> >                               char const *const txtname,
> >                               uint_t *const recvalp,
> >                               unsigned int *sym_index,
> >                               Elf_Shdr const *const symhdr,
> >                               Elf32_Word const *symtab,
> >                               Elf32_Word const *symtab_shndx,
> >                               Elf_Ehdr const *const ehdr)
> > {
> >        ...
> >               if (txtndx == get_symindex(symp, symtab, symtab_shndx)
> >                       /* avoid STB_WEAK */
> >
> >        fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
> >               txtndx, txtname);
> >
> >This function prints the above warning after failing to find
> >arch_kexec_kernel_verify_sig or arch_kexec_apply_relocations{_add,} in
> >section 11: .text.unlikely. because it ignores the weak symbol and ppc64le
> >doesn't its arch implementations of these functions. I'll see if I can fix
> >it in linux/scripts/recordmcount.h.
>
> After digging deeper into linux/scripts/recordmcount.h, I think this
> issue can be either fixed in the compiler or recordmcount. So I fild two bugs
> - gcc: https://bugzilla.redhat.com/show_bug.cgi?id=2059838

Hi,

I have also opened a BZ for gcc some time ago and that is where I
was redirected to this mailing list, linking it here if it helps:

https://bugzilla.redhat.com/show_bug.cgi?id=2022470


Veronika

> - linux/scripts/recordmcount.h: https://bugzilla.redhat.com/show_bug.cgi?id=2059842
>
> >
> >>>
> >>>
> >>>>
> >>>>Thanks
> >>>>Baoquan
> >>>>
> >>>
> >>>--
> >>>Best regards,
> >>>Coiby
> >>
> >
> >--
> >Best regards,
> >Coiby
>
> --
> Best regards,
> Coiby
>

Compile error ppc64le: Cannot find symbol for section 11: .text.unlikely.

[Coiby Xu]

On Wed, Mar 02, 2022 at 11:52:12AM +0100, Veronika Kabatova wrote:
>On Wed, Mar 2, 2022 at 8:50 AM Coiby Xu <coxu@redhat.com> wrote:
>>
>> On Fri, Feb 25, 2022 at 11:46:41AM +0800, Coiby Xu wrote:
>> >On Fri, Dec 03, 2021 at 04:54:19PM +0100, Veronika Kabatova wrote:
>> >>On Wed, Dec 1, 2021 at 3:20 AM Coiby Xu <coxu@redhat.com> wrote:
>> >>>
>> >>>On Wed, Nov 24, 2021 at 09:47:43PM +0800, Baoquan He wrote:
>> >>>>On 11/24/21 at 01:47pm, Veronika Kabatova wrote:
>> >>>>> Hi,
>> >>>>>
>> >>>>> for a while we've been seen the following error when compiling
>> >>>>> the mainline kernel with gcc 11.2 and binutils 2.37:
>> >>>>>
>> >>>>> 00:02:32 Cannot find symbol for section 11: .text.unlikely.
>> >>>>> 00:02:32 kernel/kexec_file.o: failed
>> >>>>> 00:02:32 make[3]: *** [scripts/Makefile.build:287: kernel/kexec_file.o] Error 1
>> >>>>> 00:02:32 make[3]: *** Deleting file 'kernel/kexec_file.o'
>> >>>>> 00:02:32 make[2]: *** [Makefile:1846: kernel] Error 2
>> >>>>> 00:02:32 make[2]: *** Waiting for unfinished jobs....
>> >>>>>
>> >>>>> The error only happens with ppc64le. I've tested this with cross
>> >>>>> compilation, but the only reference to the error I found suggests
>> >>>>> the same happens with the native compiles as well:
>> >>>>>
>> >>>>> https://github.com/groeck/linux-build-test/commit/142cbefbc0d37962c9a6c7f28ee415ecd5fd1e98
>> >>>>>
>> >>>>> In case it matters, the config used is the Fedora config with
>> >>>>> kselftest options enabled, which you can grab from
>> >>>>>
>> >>>>> https://gitlab.com/redhat/red-hat-ci-tools/kernel/cki-internal-pipelines/cki-trusted-contributors/-/jobs/1760752896/artifacts/raw/artifacts/kernel-mainline.kernel.org-ppc64le-e4e737bb5c170df6135a127739a9e6148ee3da82.config
>> >>>>>
>> >>>>>
>> >>>>> I've reached out to the Fedora compiler folks and Nick Clifton
>> >>>>> suggested this is a problem with the kernel:
>> >>>>>
>> >>>>>     This message comes from the recordmcount tool, which is part of the kernel
>> >>>>>     sources:
>> >>>>>
>> >>>>>     linux/scripts/recordmcount.[ch]
>> >>>>>
>> >>>>>     It appears to be triggered when a compiler update causes code to be
>> >>>>>     rearranged. The problem has been reported before in various forums,
>> >>>>>     but in particular I found this reference:
>> >>>>>
>> >>>>>     https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd at kernel.org/
>> >>>>>
>> >>>>>     The point of which to me at least is that this is a kernel issue rather than
>> >>>>>     a compiler issue.  Ie there must be some weak symbols in kexec_file.o file
>> >>>>>     which need to be moved elsewhere.
>> >>>>
>> >>>>It could be arch_kexec_kernel_verify_sig() in kernel/kexec_file.c which
>> >>>>is __weak, but not implemented in any ARCH. If true, this has been
>> >>>>pointed out by Eric in one patch thread from Coiby.
>> >>>>
>> >>>>[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig
>> >>>>http://lkml.kernel.org/r/20211018083137.338757-2-coxu at redhat.com
>> >>>>
>> >>>>Maybe Coiby can fetch above config file and run the test to check.
>> >>>
>> >>>"[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig" alone
>> >>>would fix the error. If I turn arch_kexec_apply_relocations{_add,} into
>> >
>> >Sorry I meant "alone won't fix the error".
>> >
>> >>>static function, the error would be gone. As attached is the patch would
>> >>>make this error disappear.
>> >>>
>> >>
>> >>Thank you! I can confirm the attached patch fixes the problem.
>> >>
>> >>
>> >>Veronika
>> >>
>> >>>However, s390 and x86 have its own implementation of
>> >>>arch_kexec_apply_relocations_add. This makes it looks like to be gcc's
>> >>>issue.
>> >
>> >Based on the above point and further investigation, I think the root cause is
>> >find_secsym_ndx in linux/scripts/recordmcount.h,
>> > /*
>> >  * Find a symbol in the given section, to be used as the base for relocating
>> >  * the table of offsets of calls to mcount.  A local or global symbol suffices,
>> >  * but avoid a Weak symbol because it may be overridden; the change in value
>> >  * would invalidate the relocations of the offsets of the calls to mcount.
>> >  * Often the found symbol will be the unnamed local symbol generated by
>> >  * GNU 'as' for the start of each section.  For example:
>> >  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
>> >  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
>> >  */
>> > static int find_secsym_ndx(unsigned const txtndx,
>> >                               char const *const txtname,
>> >                               uint_t *const recvalp,
>> >                               unsigned int *sym_index,
>> >                               Elf_Shdr const *const symhdr,
>> >                               Elf32_Word const *symtab,
>> >                               Elf32_Word const *symtab_shndx,
>> >                               Elf_Ehdr const *const ehdr)
>> > {
>> >        ...
>> >               if (txtndx == get_symindex(symp, symtab, symtab_shndx)
>> >                       /* avoid STB_WEAK */
>> >
>> >        fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
>> >               txtndx, txtname);
>> >
>> >This function prints the above warning after failing to find
>> >arch_kexec_kernel_verify_sig or arch_kexec_apply_relocations{_add,} in
>> >section 11: .text.unlikely. because it ignores the weak symbol and ppc64le
>> >doesn't its arch implementations of these functions. I'll see if I can fix
>> >it in linux/scripts/recordmcount.h.
>>
>> After digging deeper into linux/scripts/recordmcount.h, I think this
>> issue can be either fixed in the compiler or recordmcount. So I fild two bugs
>> - gcc: https://bugzilla.redhat.com/show_bug.cgi?id=2059838
>
>Hi,
>
>I have also opened a BZ for gcc some time ago and that is where I
>was redirected to this mailing list, linking it here if it helps:
>
>https://bugzilla.redhat.com/show_bug.cgi?id=2022470

Hi,

Thanks for the info. Sorry I didn't notice this bug. But I will use
bz2059838 since I already gave almost the decisive evidence showing
there is something wrong with Fedora's gcc in bz2059838. 

>
>
>Veronika
>
>> - linux/scripts/recordmcount.h: https://bugzilla.redhat.com/show_bug.cgi?id=2059842
>>
>> >
>> >>>
>> >>>
>> >>>>
>> >>>>Thanks
>> >>>>Baoquan
>> >>>>
>> >>>
>> >>>--
>> >>>Best regards,
>> >>>Coiby
>> >>
>> >
>> >--
>> >Best regards,
>> >Coiby
>>
>> --
>> Best regards,
>> Coiby
>>
>

-- 
Best regards,
Coiby