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From: "boudewijn83 at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug breakpoints/31481] Certain instructions load the wrong RIP-relative memory after setting a breakpoint
Date: Thu, 14 Mar 2024 16:35:10 +0000	[thread overview]
Message-ID: <bug-31481-4717-Dt0eI23nbD@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-31481-4717@http.sourceware.org/bugzilla/>

https://sourceware.org/bugzilla/show_bug.cgi?id=31481

--- Comment #2 from Boudewijn <boudewijn83 at gmail dot com> ---
Oh hey, that might be it!

I did some hacking:

At each of the buggy instructions "fixup_displaced_copy" in amd64-tdep.c gets
called with "detail->modrm_offset" still set to -1, even though all the
instructions have a ModRM byte.

And with modrm_offset == -1 it never calls "fixup_riprel".

So I think the fix is to:

- add lookup tables for the VEX-prefixed opcode maps 1-3
- use those in amd64_get_insn_details, whenever vex2_prefix_p(*insn) or
vex3_prefix_p(*insn)

Something like that?

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  parent reply	other threads:[~2024-03-14 16:35 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-14  1:55 [Bug breakpoints/31481] New: " boudewijn83 at gmail dot com
2024-03-14 13:01 ` [Bug breakpoints/31481] " tromey at sourceware dot org
2024-03-14 16:35 ` boudewijn83 at gmail dot com [this message]
2024-03-14 20:29 ` tromey at sourceware dot org
2024-03-14 22:43 ` sam at gentoo dot org
2024-03-16 11:54 ` boudewijn83 at gmail dot com
2024-03-16 17:39 ` tromey at sourceware dot org

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