From: Milian Wolff <mail@milianw.de>
To: elfutils-devel@sourceware.org
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>,
Mark Wielaard <mark@klomp.org>, Ulf Hermann <ulf.hermann@qt.io>
Subject: Re: frame unwinding patches
Date: Tue, 04 Apr 2017 07:40:00 -0000 [thread overview]
Message-ID: <2050042.dvQtNuZMzI@milian-kdab2> (raw)
In-Reply-To: <20170403212325.GA21599@host1.jankratochvil.net>
On Monday, April 3, 2017 11:23:25 PM CEST Jan Kratochvil wrote:
> On Mon, 03 Apr 2017 11:00:03 +0200, Milian Wolff wrote:
> > I just got a report from a colleague. As-is, elfutils would fail to unwind
> > from the following location in his application:
> >
> > 0x1137ca4
>
> > With the x86_64 patch applied, he got a proper backtrace:
>
> S/he has something wrong with the compiler. With
> -fasynchronous-unwind-tables frame pointer unwinding is never needed
> and gcc defaults to -fasynchronous-unwind-tables on x86_64.
>
> This is why I haven't implemented it originally as it only paper overs the
> real problem and it leads to unreliable backtraces in longterm.
Please reconsider:
- In the example above, the address points into libnvidia-glcore.so and as
such not compiled by my colleague but rather provided by NVidia as a binary
blob. When you only got a binary blob and have to make do with it, you cannot
tell people to "just fix the compiler invocation".
- Some JIT compilers, like QV4, actually embed frame pointers into their
dynamic code, but do not go the extra mile for generating DWARF data or
asynchronous unwind tables. That is another case where the patches by Ulf
excel and make elfutils much more useful.
Please, as a user of elfutils I strongly hope that this patch set gets
accepted. In general, similar patches that make it more resilient in the face
of broken setups should also at least get considered instead of right-out
rejected because "something is broken". Things break all the time, but
developers often have to live with the brokenness.
Cheers
--
Milian Wolff
mail@milianw.de
http://milianw.de
next prev parent reply other threads:[~2017-04-04 7:40 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-15 23:34 Mark Wielaard
2017-02-15 23:34 ` [PATCH 3/3] Add frame pointer unwinding for aarch64 Mark Wielaard
2017-02-15 23:34 ` [PATCH 1/3] Add frame pointer unwinding as fallback on x86_64 Mark Wielaard
2017-02-15 23:34 ` [PATCH 2/3] Add frame pointer unwinding as fallback on arm Mark Wielaard
2017-02-16 9:13 ` frame unwinding patches Ulf Hermann
2017-04-03 9:00 ` Milian Wolff
2017-04-03 9:03 ` Ulf Hermann
2017-04-03 21:14 ` Mark Wielaard
2017-04-07 10:27 ` Mark Wielaard
2017-04-11 10:16 ` Ulf Hermann
2017-04-19 19:48 ` Mark Wielaard
2017-04-20 9:26 ` Ulf Hermann
2017-04-25 12:50 ` Mark Wielaard
2017-04-25 12:54 ` [PATCH 1/5] Revert "Optionally allow unknown symbols in the backtrace tests" Mark Wielaard
2017-04-25 12:50 ` [PATCH 2/5] tests: Add core backtracegen chec and regenerate ppc32 backtrace test files Mark Wielaard
2017-04-25 13:04 ` Ulf Hermann
2017-04-25 12:55 ` [PATCH 3/5] Add frame pointer unwinding as fallback on x86_64 Mark Wielaard
2017-04-25 13:05 ` Ulf Hermann
2017-04-25 12:56 ` [PATCH 4/5] Add i386 frame pointer unwinder Mark Wielaard
2017-04-25 13:38 ` Ulf Hermann
2017-04-25 12:56 ` [PATCH 1/5] Revert "Optionally allow unknown symbols in the backtrace tests" Ulf Hermann
2017-04-25 13:11 ` [PATCH 5/5] Add frame pointer unwinding for aarch64 Mark Wielaard
2017-04-25 21:55 ` Ulf Hermann
2017-04-25 22:13 ` Mark Wielaard
2017-04-25 22:23 ` Ulf Hermann
2017-04-26 15:24 ` Mark Wielaard
2017-04-27 14:02 ` Ulf Hermann
2017-04-27 14:29 ` Mark Wielaard
2017-04-27 14:35 ` Ulf Hermann
2017-04-27 15:09 ` Mark Wielaard
2017-04-27 15:42 ` Ulf Hermann
2017-05-03 8:46 ` Mark Wielaard
2017-04-26 15:20 ` frame unwinding patches Ulf Hermann
2017-04-03 21:23 ` Jan Kratochvil
2017-04-04 7:40 ` Milian Wolff [this message]
2017-04-04 7:55 ` Jan Kratochvil
2017-04-04 8:25 ` Ulf Hermann
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=2050042.dvQtNuZMzI@milian-kdab2 \
--to=mail@milianw.de \
--cc=elfutils-devel@sourceware.org \
--cc=jan.kratochvil@redhat.com \
--cc=mark@klomp.org \
--cc=ulf.hermann@qt.io \
/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.
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 read-only IMAP folder(s) and NNTP newsgroup(s).