From: Tejun Heo <tj@kernel.org>
To: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: oleg@redhat.com, vda.linux@googlemail.com,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
akpm@linux-foundation.org, indan@nul.nu
Subject: Re: getter PTRACE_GETSIGINFO should not modify anything [Re: [PATCH 11/11] ptrace: implement group stop notification for ptracer]
Date: Mon, 16 May 2011 14:56:15 +0200 [thread overview]
Message-ID: <20110516125615.GW23665@htj.dyndns.org> (raw)
In-Reply-To: <20110516121711.GC10469@host1.jankratochvil.net>
Hello,
On Mon, May 16, 2011 at 02:17:11PM +0200, Jan Kratochvil wrote:
> On Mon, 16 May 2011 10:43:50 +0200, Tejun Heo wrote:
> > There's distinction between "broken" and "ugly". If it's ugly but
> > functional, you don't need to "fix" it.
>
> The final goal is the user experience (such as the users of GDB), nothing else
> matters. If it is so "ugly" the userland developers fail to use it the
> project as a whole still broken.
To me, it seems the breakage and mountain of workarounds come more
from lack of proper documentation plus the current ptrace + job
control + signal interaction which is really broken. For example, it
seems nobody really understood how group stop and ptrace interacts and
the different types of traps being used - strace(2) thought the same
signal was being delivered twice.
> > So, I'm gonna push back quite a bit unless it actually compromises
> > functionality or correctness.
>
> With your position "if it is workaroundable in userland let's make the new
> kernel API broken again" it no longer makes sense to comment on it. Yes,
> everything is workaroundable but that is usually not the goal of new APIs.
First of all, let's distinguish "broken" and "ugly" properly and
please keep in mind that what's broken is broken but beauty is in the
eyes of the beholder.
Secondly, I'm listening to your comments and will incorporate them, so
please don't give up so easily.
Thank you.
--
tejun
next prev parent reply other threads:[~2011-05-16 12:56 UTC|newest]
Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-08 15:48 [PATCHSET ptrace] ptrace: implement PTRACE_SEIZE/INTERRUPT and group stop notification Tejun Heo
2011-05-08 15:48 ` [PATCH 01/11] job control: rename signal->group_stop and flags to jobctl and rearrange flags Tejun Heo
2011-05-08 15:48 ` [PATCH 02/11] ptrace: implement PTRACE_SEIZE Tejun Heo
2011-05-09 16:18 ` Oleg Nesterov
2011-05-10 9:46 ` Tejun Heo
2011-05-10 13:20 ` Oleg Nesterov
2011-05-10 13:47 ` Tejun Heo
2011-05-10 18:19 ` Oleg Nesterov
2011-05-15 15:56 ` PTRACE_SEIZE should not stop [Re: [PATCH 02/11] ptrace: implement PTRACE_SEIZE] Jan Kratochvil
2011-05-15 16:26 ` Tejun Heo
2011-05-15 17:15 ` Jan Kratochvil
2011-05-15 17:25 ` Tejun Heo
2011-05-15 19:48 ` Jan Kratochvil
2011-05-16 8:31 ` Tejun Heo
2011-05-16 12:26 ` Jan Kratochvil
2011-05-16 12:42 ` Tejun Heo
2011-05-16 13:03 ` Jan Kratochvil
2011-05-16 13:51 ` Tejun Heo
2011-05-16 13:21 ` Jan Kratochvil
2011-05-16 13:45 ` Tejun Heo
2011-05-16 13:48 ` Jan Kratochvil
2011-05-16 13:54 ` Tejun Heo
2011-05-08 15:48 ` [PATCH 03/11] ptrace: ptrace_check_attach(): rename @kill to @ignore_state and add comments Tejun Heo
2011-05-08 15:48 ` [PATCH 04/11] ptrace: implement PTRACE_INTERRUPT Tejun Heo
2011-05-08 21:58 ` Denys Vlasenko
2011-05-09 10:09 ` Tejun Heo
2011-05-09 10:55 ` Denys Vlasenko
2011-05-09 16:58 ` Oleg Nesterov
2011-05-10 9:50 ` Tejun Heo
2011-05-10 14:06 ` Oleg Nesterov
2011-05-10 14:20 ` Tejun Heo
2011-05-10 18:08 ` Oleg Nesterov
2011-05-11 8:29 ` Tejun Heo
2011-05-12 17:06 ` Oleg Nesterov
2011-05-12 17:21 ` Tejun Heo
2011-05-10 21:59 ` Denys Vlasenko
2011-05-11 9:19 ` Tejun Heo
2011-05-11 12:23 ` Denys Vlasenko
2011-05-11 13:22 ` Tejun Heo
2011-05-11 16:20 ` Bryan Donlan
2011-05-11 19:24 ` Tejun Heo
2011-05-15 16:10 ` PTRACE_DETACH without stop [Re: [PATCH 04/11] ptrace: implement PTRACE_INTERRUPT] Jan Kratochvil
2011-05-15 16:35 ` Tejun Heo
2011-05-15 17:39 ` Jan Kratochvil
2011-05-16 9:01 ` Tejun Heo
2011-05-16 12:08 ` Jan Kratochvil
2011-05-16 12:24 ` Tejun Heo
2011-05-08 15:48 ` [PATCH 05/11] ptrace: restructure ptrace_getsiginfo() Tejun Heo
2011-05-08 15:49 ` [PATCH 06/11] ptrace: make group stop state visible via PTRACE_GETSIGINFO Tejun Heo
2011-05-10 16:55 ` Oleg Nesterov
2011-05-10 17:11 ` Oleg Nesterov
2011-05-11 8:08 ` Tejun Heo
2011-05-12 16:47 ` Oleg Nesterov
2011-05-12 17:15 ` Tejun Heo
2011-05-08 15:49 ` [PATCH 07/11] ptrace: add JOBCTL_TRAPPED Tejun Heo
2011-05-08 15:49 ` [PATCH 08/11] ptrace: move fallback JOBCTL_TRAPPING clearing to get_signal_to_deliver() Tejun Heo
2011-05-11 15:48 ` Oleg Nesterov
2011-05-11 19:17 ` Tejun Heo
2011-05-12 15:40 ` Oleg Nesterov
2011-05-08 15:49 ` [PATCH 09/11] job control: reorganize wait_task_stopped() Tejun Heo
2011-05-11 15:48 ` Oleg Nesterov
2011-05-11 19:29 ` Tejun Heo
2011-05-12 15:42 ` Oleg Nesterov
2011-05-12 16:02 ` Tejun Heo
2011-05-12 17:25 ` Oleg Nesterov
2011-05-12 17:32 ` Tejun Heo
2011-05-12 17:33 ` Tejun Heo
2011-05-12 18:33 ` Oleg Nesterov
2011-05-13 8:46 ` Tejun Heo
2011-05-13 17:21 ` Oleg Nesterov
2011-05-14 10:56 ` Tejun Heo
2011-05-15 14:40 ` waitpid(WNOHANG) should report SIGCHLD-notified signals [Re: [PATCH 09/11] job control: reorganize wait_task_stopped()] Jan Kratochvil
2011-05-15 16:47 ` Tejun Heo
2011-05-15 17:01 ` Tejun Heo
2011-05-15 17:47 ` Jan Kratochvil
2011-05-16 9:13 ` Tejun Heo
2011-05-16 12:11 ` Jan Kratochvil
2011-05-16 12:27 ` Tejun Heo
2011-05-16 12:39 ` Jan Kratochvil
2011-05-16 12:46 ` Tejun Heo
2011-05-08 15:49 ` [PATCH 10/11] ptrace: move JOBCTL_TRAPPING wait to wait(2) and ptrace_check_attach() Tejun Heo
2011-05-11 16:49 ` Oleg Nesterov
2011-05-11 17:00 ` Oleg Nesterov
2011-05-11 19:45 ` Tejun Heo
2011-05-11 19:53 ` Tejun Heo
2011-05-12 10:23 ` Tejun Heo
2011-05-12 16:06 ` Oleg Nesterov
2011-05-12 15:59 ` Oleg Nesterov
2011-05-12 16:07 ` Tejun Heo
2011-05-12 18:20 ` Oleg Nesterov
2011-05-13 9:13 ` Tejun Heo
2011-05-13 18:34 ` Oleg Nesterov
2011-05-08 15:49 ` [PATCH 11/11] ptrace: implement group stop notification for ptracer Tejun Heo
2011-05-08 22:42 ` Denys Vlasenko
2011-05-09 10:10 ` Tejun Heo
2011-05-10 22:37 ` Denys Vlasenko
2011-05-11 9:05 ` Tejun Heo
2011-05-11 12:01 ` Denys Vlasenko
2011-05-11 13:13 ` Tejun Heo
2011-05-11 19:58 ` Oleg Nesterov
2011-05-11 20:18 ` Tejun Heo
2011-05-11 20:21 ` Tejun Heo
2011-05-12 10:24 ` Tejun Heo
2011-05-15 14:02 ` getter PTRACE_GETSIGINFO should not modify anything [Re: [PATCH 11/11] ptrace: implement group stop notification for ptracer] Jan Kratochvil
2011-05-15 14:28 ` Tejun Heo
2011-05-15 17:17 ` Jan Kratochvil
2011-05-15 17:28 ` Tejun Heo
2011-05-15 20:06 ` Jan Kratochvil
2011-05-16 8:43 ` Tejun Heo
2011-05-16 12:17 ` Jan Kratochvil
2011-05-16 12:56 ` Tejun Heo [this message]
2011-05-16 13:00 ` Ingo Molnar
2011-05-08 22:27 ` [PATCHSET ptrace] ptrace: implement PTRACE_SEIZE/INTERRUPT and group stop notification Denys Vlasenko
2011-05-09 9:48 ` Tejun Heo
2011-05-15 13:55 ` ptrace-testsuite status [Re: [PATCHSET ptrace] ptrace: implement PTRACE_SEIZE/INTERRUPT and group stop notification] Jan Kratochvil
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=20110516125615.GW23665@htj.dyndns.org \
--to=tj@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=indan@nul.nu \
--cc=jan.kratochvil@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=torvalds@linux-foundation.org \
--cc=vda.linux@googlemail.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.
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).