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From: "ssbssa at sourceware dot org" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug external/8841] Can not set breakpoints in the vsyscall page
Date: Sun, 14 Jan 2024 14:31:20 +0000 [thread overview]
Message-ID: <bug-8841-4717-arnhkF4Bj2@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-8841-4717@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=8841
Hannes Domani <ssbssa at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ssbssa at sourceware dot org
--- Comment #7 from Hannes Domani <ssbssa at sourceware dot org> ---
(In reply to Sourceware Commits from comment #6)
> The master branch has been updated by Yao Qi <qiyao@sourceware.org>:
>
> https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;
> h=7eb895307f53af3435440d3fe67c0e4e679d99b2
>
> commit 7eb895307f53af3435440d3fe67c0e4e679d99b2
> Author: Yao Qi <yao.qi@arm.com>
> Date: Mon May 23 17:32:56 2016 +0100
>
> Skip unwritable frames in command "finish"
>
> Nowadays, GDB can't insert breakpoint on the return address of the
> exception handler on ARM M-profile, because the address is a magic
> one 0xfffffff9,
>
> (gdb) bt
> #0 CT32B1_IRQHandler () at ../src/timer.c:67
> #1 <signal handler called>
> #2 main () at ../src/timer.c:127
>
> (gdb) info frame
> Stack level 0, frame at 0x200ffa8:
> pc = 0x4ec in CT32B1_IRQHandler (../src/timer.c:67); saved pc =
> 0xfffffff9
> called by frame at 0x200ffc8
> source language c.
> Arglist at 0x200ffa0, args:
> Locals at 0x200ffa0, Previous frame's sp is 0x200ffa8
> Saved registers:
> r7 at 0x200ffa0, lr at 0x200ffa4
>
> (gdb) x/x 0xfffffff9
> 0xfffffff9: Cannot access memory at address 0xfffffff9
>
> (gdb) finish
> Run till exit from #0 CT32B1_IRQHandler () at ../src/timer.c:67
> Ed:15: Target error from Set break/watch: Et:96: Pseudo-address
> (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
>
> Warning:
> Cannot insert hardware breakpoint 0.
> Could not insert hardware breakpoints:
> You may have requested too many hardware breakpoints/watchpoints.
>
> Command aborted.
>
> even some debug probe can't set hardware breakpoint on the magic
> address too,
>
> (gdb) hbreak *0xfffffff9
> Hardware assisted breakpoint 2 at 0xfffffff9
> (gdb) c
> Continuing.
> Ed:15: Target error from Set break/watch: Et:96: Pseudo-address
> (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
>
> Warning:
> Cannot insert hardware breakpoint 2.
> Could not insert hardware breakpoints:
> You may have requested too many hardware breakpoints/watchpoints.
>
> Command aborted.
>
> The problem described above is quite similar to PR 8841, in which GDB
> can't set breakpoint on signal trampoline, which is mapped to a read-only
> page by kernel. The rationale of this patch is to skip "unwritable"
> frames when looking for caller frames in command "finish", and a new
> gdbarch method code_of_frame_writable is added. This patch fixes
> the problem on ARM cortex-m target, but it can be used to fix
> PR 8841 too.
Can this be closed?
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next prev parent reply other threads:[~2024-01-14 14:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-8841-4717@http.sourceware.org/bugzilla/>
2012-03-04 8:03 ` kalvdans at gmail dot com
2012-03-04 8:10 ` jan.kratochvil at redhat dot com
2012-03-04 20:09 ` kalvdans at gmail dot com
2012-03-04 20:35 ` jan.kratochvil at redhat dot com
2015-04-16 20:13 ` sandra at codesourcery dot com
2024-01-14 14:31 ` ssbssa at sourceware dot org [this message]
2024-01-14 16:27 ` sandra.oss at frogsonice dot com
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