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From: "luis.machado at arm dot com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug gdb/28947] GDB does not remove AArch64 pointer signatures
 before doing memory accesses
Date: Tue, 24 May 2022 08:04:15 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D28947

--- Comment #3 from Luis Machado <luis.machado at arm dot com> ---
Thinking a bit more about this, I'm not sure if GDB/debuggers should go out=
 of
their way to remove signature bits from the pointers.

Accessing memory using a signed pointer is invalid anyway, and will result =
in a
fault. Having debuggers remove that information may cause confusion for a
developer that is trying to debug a PAC-related crash of some kind, as it w=
ill
not show the signature part of the pointer.

I can imagine a scenario where a pointer wasn't signed properly, but GDB wi=
ll
strip the signature of that pointer and will show things as if they were
correct, when in fact they are not. Does that make sense?

Accessing memory using a tagged pointer is valid though, but debuggers need=
 to
be cautious not to pass tagged pointers down to syscalls. GDB does this.

--=20
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