Re: git: 753a166bdeb3 - main - imgact_elf: Fix uninitialized variable use in note_procstat_auxv

On 25 Apr 2026, at 14:42, Dimitry Andric <dim@FreeBSD.org> wrote:

> The branch main has been updated by dim:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=753a166bdeb3aeba02fd9678e7360f0929007368
> 
> commit 753a166bdeb3aeba02fd9678e7360f0929007368
> Author:     Alex Richardson <arichardson@FreeBSD.org>
> AuthorDate: 2025-09-15 06:27:12 +0000
> Commit:     Dimitry Andric <dim@FreeBSD.org>
> CommitDate: 2026-04-25 13:42:16 +0000
> 
>    imgact_elf: Fix uninitialized variable use in note_procstat_auxv
> 
>    Found building with latest clang
> 
>    MFC after:      3 days
> ---
> sys/kern/imgact_elf.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
> index af0841c75549..3c5fbe4df342 100644
> --- a/sys/kern/imgact_elf.c
> +++ b/sys/kern/imgact_elf.c
> @@ -2712,13 +2712,16 @@ __elfN(note_procstat_auxv)(void *arg, struct sbuf *sb, size_t *sizep)
> struct proc *p;
> size_t size;
> int structsize;
> -
> +#if defined(COMPAT_FREEBSD32) && __ELF_WORD_SIZE == 32
> + structsize = sizeof(Elf32_Auxinfo);

Elf_Auxinfo *is* Elf32_Auxinfo for __ELF_WORD_SIZE == 32?

> +#else
> + structsize = sizeof(Elf_Auxinfo);
> +#endif
> p = arg;
> structsize = sizeof(Elf_Auxinfo);

But it’s initialised right here? So that assignment is dead?

> if (sb == NULL) {
> size = 0;
> - sb = sbuf_new(NULL, NULL, AT_COUNT * sizeof(Elf_Auxinfo),
> -    SBUF_FIXEDLEN);
> + sb = sbuf_new(NULL, NULL, AT_COUNT * structsize, SBUF_FIXEDLEN);

These are equivalent? Though this one at least I see an argument for.

> sbuf_set_drain(sb, sbuf_count_drain, &size);
> sbuf_bcat(sb, &structsize, sizeof(structsize));
> PHOLD(p);
> 

I really don’t understand this change at all. I think all but the final
part should be reverted.

Jessica