The routine to search a symbol in ELF can be shared, so split it out.
Signed-off-by: Pingfan Liu <piliu@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Philipp Rudo <prudo@redhat.com>
To: kexec@lists.infradead.org
---
kernel/kexec_file.c | 61 +++++++++++++++++++++++++++++++++++++++++
kernel/kexec_internal.h | 1 +
2 files changed, 62 insertions(+)
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index aca265034b4ed..15857a56e6278 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -902,6 +902,51 @@ static int kexec_calculate_store_digests(struct kimage *image)
return ret;
}
+#if defined(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY) || defined(CONFIG_KEXEC_BPF)
+const Elf_Sym *elf_find_symbol(const Elf_Ehdr *ehdr, const char *name)
+{
+ const Elf_Shdr *sechdrs;
+ const Elf_Sym *syms;
+ const char *strtab;
+ int i, k;
+
+ sechdrs = (void *)ehdr + ehdr->e_shoff;
+
+ for (i = 0; i < ehdr->e_shnum; i++) {
+ if (sechdrs[i].sh_type != SHT_SYMTAB)
+ continue;
+
+ if (sechdrs[i].sh_link >= ehdr->e_shnum)
+ /* Invalid strtab section number */
+ continue;
+ strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
+ syms = (void *)ehdr + sechdrs[i].sh_offset;
+
+ /* Go through symbols for a match */
+ for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
+ if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
+ continue;
+
+ if (strcmp(strtab + syms[k].st_name, name) != 0)
+ continue;
+
+ if (syms[k].st_shndx == SHN_UNDEF ||
+ syms[k].st_shndx >= ehdr->e_shnum) {
+ pr_debug("Symbol: %s has bad section index %d.\n",
+ name, syms[k].st_shndx);
+ return NULL;
+ }
+
+ /* Found the symbol we are looking for */
+ return &syms[k];
+ }
+ }
+
+ return NULL;
+}
+
+#endif
+
#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
/*
* kexec_purgatory_find_symbol - find a symbol in the purgatory
@@ -1221,6 +1266,22 @@ int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
return ret;
}
+/*
+ * kexec_purgatory_find_symbol - find a symbol in the purgatory
+ * @pi: Purgatory to search in.
+ * @name: Name of the symbol.
+ *
+ * Return: pointer to symbol in read-only symtab on success, NULL on error.
+ */
+static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
+ const char *name)
+{
+ if (!pi->ehdr)
+ return NULL;
+
+ return elf_find_symbol(pi->ehdr, name);
+}
+
void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
{
struct purgatory_info *pi = &image->purgatory_info;
diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
index 731ff02110b3c..224f09188db23 100644
--- a/kernel/kexec_internal.h
+++ b/kernel/kexec_internal.h
@@ -40,6 +40,7 @@ void kimage_file_post_load_cleanup(struct kimage *image);
extern char kexec_purgatory[];
extern size_t kexec_purgatory_size;
extern int decompose_kexec_image(struct kimage *image, int extended_fd);
+extern const Elf_Sym *elf_find_symbol(const Elf_Ehdr *ehdr, const char *name);
#else /* CONFIG_KEXEC_FILE */
static inline void kimage_file_post_load_cleanup(struct kimage *image) { }
#endif /* CONFIG_KEXEC_FILE */
--
2.49.0Hi Pingfan,
kernel test robot noticed the following build errors:
[auto build test ERROR on bpf-next/net]
[also build test ERROR on bpf-next/master bpf/master akpm-mm/mm-nonmm-unstable linus/master v7.0-rc5 next-20260320]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Pingfan-Liu/bpf-Introduce-kfuncs-to-parser-buffer-content/20260323-084500
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git net
patch link: https://lore.kernel.org/r/20260322014402.8815-9-piliu%40redhat.com
patch subject: [PATCHv7 08/13] kexec_file: Factor out routine to find a symbol in ELF
config: x86_64-randconfig-002-20260323 (https://download.01.org/0day-ci/archive/20260323/202603231812.ZGRRlzPe-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260323/202603231812.ZGRRlzPe-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603231812.ZGRRlzPe-lkp@intel.com/
All errors (new ones prefixed by >>):
>> kernel/kexec_file.c:1276:23: error: redefinition of 'kexec_purgatory_find_symbol'
1276 | static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/kexec_file.c:958:23: note: previous definition of 'kexec_purgatory_find_symbol' with type 'const Elf64_Sym *(struct purgatory_info *, const char *)' {aka 'const struct elf64_sym *(struct purgatory_info *, const char *)'}
958 | static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +/kexec_purgatory_find_symbol +1276 kernel/kexec_file.c
1268
1269 /*
1270 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1271 * @pi: Purgatory to search in.
1272 * @name: Name of the symbol.
1273 *
1274 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1275 */
> 1276 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1277 const char *name)
1278 {
1279 if (!pi->ehdr)
1280 return NULL;
1281
1282 return elf_find_symbol(pi->ehdr, name);
1283 }
1284
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Pingfan,
kernel test robot noticed the following build errors:
[auto build test ERROR on bpf-next/net]
[also build test ERROR on bpf-next/master bpf/master akpm-mm/mm-nonmm-unstable linus/master v7.0-rc5 next-20260320]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Pingfan-Liu/bpf-Introduce-kfuncs-to-parser-buffer-content/20260323-084500
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git net
patch link: https://lore.kernel.org/r/20260322014402.8815-9-piliu%40redhat.com
patch subject: [PATCHv7 08/13] kexec_file: Factor out routine to find a symbol in ELF
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20260323/202603230851.qOD27RaS-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260323/202603230851.qOD27RaS-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603230851.qOD27RaS-lkp@intel.com/
All errors (new ones prefixed by >>):
>> kernel/kexec_file.c:1276:23: error: redefinition of 'kexec_purgatory_find_symbol'
1276 | static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
| ^
kernel/kexec_file.c:958:23: note: previous definition is here
958 | static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
| ^
1 error generated.
vim +/kexec_purgatory_find_symbol +1276 kernel/kexec_file.c
1268
1269 /*
1270 * kexec_purgatory_find_symbol - find a symbol in the purgatory
1271 * @pi: Purgatory to search in.
1272 * @name: Name of the symbol.
1273 *
1274 * Return: pointer to symbol in read-only symtab on success, NULL on error.
1275 */
> 1276 static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
1277 const char *name)
1278 {
1279 if (!pi->ehdr)
1280 return NULL;
1281
1282 return elf_find_symbol(pi->ehdr, name);
1283 }
1284
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
[ ... ]
> @@ -1221,6 +1266,22 @@ int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
> return ret;
> }
>
> +/*
> + * kexec_purgatory_find_symbol - find a symbol in the purgatory
> + * @pi: Purgatory to search in.
> + * @name: Name of the symbol.
> + *
> + * Return: pointer to symbol in read-only symtab on success, NULL on error.
> + */
> +static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
> + const char *name)
> +{
> + if (!pi->ehdr)
> + return NULL;
> +
> + return elf_find_symbol(pi->ehdr, name);
> +}
This adds a new wrapper kexec_purgatory_find_symbol() here, but the
original full implementation of kexec_purgatory_find_symbol() earlier
in the file was not removed:
kernel/kexec_file.c:kexec_purgatory_find_symbol() {
...
ehdr = pi->ehdr;
sechdrs = (void *)ehdr + ehdr->e_shoff;
for (i = 0; i < ehdr->e_shnum; i++) {
...
}
return NULL;
}
Both definitions are static and live inside the same
#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY block, so this will fail
to compile on any architecture that selects that config (x86, s390,
powerpc, riscv).
It looks like the old function body should have been replaced with
the new elf_find_symbol() wrapper, as was done in v5 of this series.
Was the deletion of the old body lost during a rebase?
---
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CI run summary: https://github.com/kernel-patches/bpf/actions/runs/23393379437
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