Hi mustafa,
On Tue, Nov 3, 2026 at 2:56 AM mustafa <[email protected]> wrote:
>
> print_debug_frame_section called alloca for every CIE in the section
> and kept them on a list. The number of CIEs depends only on the size of
> the input file, so a large .eh_frame or .debug_frame exhausts the stack.
>
> Use xmalloc and free the list through a cleanup attribute. This needs
> struct cieinfo at file scope.
>
> Signed-off-by: mohammed mustafa <[email protected]>
> ---
> src/readelf.c | 37 +++++++++++++++++++++++++------------
> 1 file changed, 25 insertions(+), 12 deletions(-)
>
> diff --git a/src/readelf.c b/src/readelf.c
> index ba47f361..12118b4f 100644
> --- a/src/readelf.c
> +++ b/src/readelf.c
> @@ -6805,6 +6805,29 @@ print_encoding_base (const char *pfx, unsigned
> int fde_encoding)
> }
>
>
> +struct cieinfo
> +{
> + ptrdiff_t cie_offset;
> + const char *augmentation;
> + unsigned int code_alignment_factor;
> + unsigned int data_alignment_factor;
> + uint8_t address_size;
> + uint8_t fde_encoding;
> + uint8_t lsda_encoding;
> + struct cieinfo *next;
> +};
> +
> +static void
> +free_cies (struct cieinfo **cies)
> +{
> + while (*cies != NULL)
> + {
> + struct cieinfo *next = (*cies)->next;
> + free (*cies);
> + *cies = next;
> + }
> +}
> +
> static void
> print_debug_frame_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
> Elf_Scn *scn, GElf_Shdr *shdr, Dwarf *dbg)
> @@ -6850,17 +6873,7 @@ print_debug_frame_section (Dwfl_Module
> *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
> \nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"),
> elf_ndxscn (scn), scnname, (uint64_t) shdr->sh_offset);
>
> - struct cieinfo
> - {
> - ptrdiff_t cie_offset;
> - const char *augmentation;
> - unsigned int code_alignment_factor;
> - unsigned int data_alignment_factor;
> - uint8_t address_size;
> - uint8_t fde_encoding;
> - uint8_t lsda_encoding;
> - struct cieinfo *next;
> - } *cies = NULL;
> + struct cieinfo *cies __attribute__ ((cleanup (free_cies))) = NULL;
Please avoid the cleanup attribute as mentioned in a previous review.
Aaron
>
> const unsigned char *readp = data->d_buf;
> const unsigned char *const dataend = ((unsigned char *) data->d_buf
> @@ -7058,7 +7071,7 @@ print_debug_frame_section (Dwfl_Module *dwflmod,
> Ebl *ebl, GElf_Ehdr *ehdr,
>
> if (likely (ptr_size == 4 || ptr_size == 8))
> {
> - struct cieinfo *newp = alloca (sizeof (*newp));
> + struct cieinfo *newp = xmalloc (sizeof (*newp));
> newp->cie_offset = offset;
> newp->augmentation = augmentation;
> newp->fde_encoding = fde_encoding;
> --
> 2.53.0
>
