From: Richard Biener <richard.guenther@gmail.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH releases/gcc-13 1/2] libgcc: Fix eh_frame fast path in find_fde_tail
Date: Tue, 18 Jul 2023 16:56:00 +0200 [thread overview]
Message-ID: <CAFiYyc1cK0T7bfGkbTEe0un6Y3aHONBUgg43ZvU1jPM3eoTkzA@mail.gmail.com> (raw)
In-Reply-To: <7302f8a2fa2f95252b32de2dc826591e75230662.1689689650.git.fweimer@redhat.com>
On Tue, Jul 18, 2023 at 4:19 PM Florian Weimer via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> The eh_frame value is only used by linear_search_fdes, not the binary
> search directly in find_fde_tail, so the bug is not immediately
> apparent with most programs.
>
> Fixes commit e724b0480bfa5ec04f39be8c7290330b495c59de ("libgcc:
> Special-case BFD ld unwind table encodings in find_fde_tail").
Both are OK to backport.
> libgcc/
>
> PR libgcc/109712
> * unwind-dw2-fde-dip.c (find_fde_tail): Correct fast path for
> parsing eh_frame.
>
> (cherry picked from commit 49310a993308492348119f4033e4db0bda4fe46a)
> ---
> libgcc/unwind-dw2-fde-dip.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libgcc/unwind-dw2-fde-dip.c b/libgcc/unwind-dw2-fde-dip.c
> index 6223f5f18a2..4e0b880513f 100644
> --- a/libgcc/unwind-dw2-fde-dip.c
> +++ b/libgcc/unwind-dw2-fde-dip.c
> @@ -403,8 +403,8 @@ find_fde_tail (_Unwind_Ptr pc,
> BFD ld generates. */
> signed value __attribute__ ((mode (SI)));
> memcpy (&value, p, sizeof (value));
> + eh_frame = p + value;
> p += sizeof (value);
> - dbase = value; /* No adjustment because pcrel has base 0. */
> }
> else
> p = read_encoded_value_with_base (hdr->eh_frame_ptr_enc,
>
> base-commit: a1322d76ca1c3c914fb818d9ba3edc291ccfa25e
> --
> 2.41.0
>
>
prev parent reply other threads:[~2023-07-18 14:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-18 14:15 Florian Weimer
2023-07-18 14:15 ` [PATCH releases/gcc-13 2/2] libgcc: Fix -Wint-conversion warning " Florian Weimer
2023-07-18 14:56 ` Richard Biener [this message]
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