mailing list of musl libc
 help / color / mirror / code / Atom feed
From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: [PATCH v2] fix x86_64 sigreturn trampoline so gdb recognizes it
Date: Sat, 12 Nov 2016 21:46:14 -0500	[thread overview]
Message-ID: <20161113024614.GQ1555@brightrain.aerifal.cx> (raw)
In-Reply-To: <20161113001205.GR5749@port70.net>

On Sun, Nov 13, 2016 at 01:12:05AM +0100, Szabolcs Nagy wrote:
> gdb can only unwind across signal handlers if it recognizes the trampoline.
> on x86_64 this means the pc must be in a function called __restore_rt or
> if gdb cannot determine the symbol name the instruction sequence must match
> to what gdb expects.
> 
> a nop is added before __restore_rt, the __restore alias is removed and
> size annotation is added to make sure gdb maps any pc value within
> __restore_rt unambigously to the __restore_rt symbol name.
> 
> and the instruction sequence got fixed to match what gdb expects.

Thanks! Committed a patch based on this as discussed on irc.

Rich


      reply	other threads:[~2016-11-13  2:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-12 17:07 [PATCH] fix x86_64 sigreturn call " Szabolcs Nagy
2016-11-13  0:12 ` [PATCH v2] fix x86_64 sigreturn trampoline " Szabolcs Nagy
2016-11-13  2:46   ` Rich Felker [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20161113024614.GQ1555@brightrain.aerifal.cx \
    --to=dalias@libc.org \
    --cc=musl@lists.openwall.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/musl/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).