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@xxxxxxxxxx/
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@xxxxxxxxxx
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
>From 49e0333f5a0743cdcc99777218524d6a6cd5ec34 Mon Sep 17 00:00:00 2001
From: Coiby Xu <coxu@xxxxxxxxxx>
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
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