Re: [PATCH] vmcoreinfo: make hwerr_data visible for debugging

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 21 Jan 2026 03:05:44 -0800 Breno Leitao <leitao@debian.org> wrote:

> If the kernel is compiled with LTO, hwerr_data symbol might be lost, and
> vmcoreinfo doesn't have it dumped. This is currently seen in some
> production kernels with LTO enabled.
> 
> Remove the static qualifier from hwerr_data so that the information is
> still preserved when the kernel is built with LTO. Making hwerr_data
> a global symbol ensures its debug info survives the LTO link process and
> appears in kallsyms.
> 
> --- a/kernel/vmcore_info.c
> +++ b/kernel/vmcore_info.c
> @@ -36,7 +36,7 @@ struct hwerr_info {
>  	time64_t timestamp;
>  };
>  
> -static struct hwerr_info hwerr_data[HWERR_RECOV_MAX];
> +struct hwerr_info hwerr_data[HWERR_RECOV_MAX];
>  
>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>  			  void *data, size_t data_len)
> 

A non-static symbol which has no external references will be made
static again by those who like to send in little fixups.  A comment
will help prevent that.  How's this?


--- a/kernel/vmcore_info.c~vmcoreinfo-make-hwerr_data-visible-for-debugging-fix
+++ a/kernel/vmcore_info.c
@@ -36,6 +36,7 @@ struct hwerr_info {
 	time64_t timestamp;
 };
 
+/* hwerr_data[] has global scope to make it available in vmcoreinfo under LTO */
 struct hwerr_info hwerr_data[HWERR_RECOV_MAX];
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
_