From: Tejun Heo <tj@kernel.org>
To: Roland McGrath <roland@redhat.com>
Cc: oleg@redhat.com, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, akpm@linux-foundation.org,
rjw@sisk.pl, jan.kratochvil@redhat.com
Subject: Re: [PATCH 16/16] ptrace: remove the extra wake_up_process() from ptrace_detach()
Date: Tue, 07 Dec 2010 14:43:08 +0100 [thread overview]
Message-ID: <4CFE39EC.40907@kernel.org> (raw)
In-Reply-To: <20101207001043.13BCE400CE@magilla.sf.frob.com>
Hello, Roland.
On 12/07/2010 01:10 AM, Roland McGrath wrote:
> The plain wake_up_process was certainly wrong from the beginning.
>
> We were conservative about changing it because of the difficulty of
> chasing all the corners where userland debuggers' behavior might be
> made to regress when it had been reliable in practice before (even
> if not always in theory, such as possible races that didn't bite in
> reality). The userland code has gone to many contortions to cope
> with how the kernel behaved in the past, whether or not that
> behavior ever made any good sense.
>
> For that sort of reason, none of this stuff should change at all in
> a -stable kernel, nor late in a release cycle.
Sure, definitely. All these changes are at the earliest for the next
merge window.
> For new kernels, I think changing the behavior in the direction of
> something that can actually be described is OK as long as userland
> debugger maintainers like Jan agree to the new behavior and that the
> behavior really and truly does follow an articulated set of rules
> that the kernel and userland sides agree to.
Yeap, that sounds good to me.
Thanks.
--
tejun
next prev parent reply other threads:[~2010-12-07 13:44 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-06 16:56 [PATCHSET] ptrace,signal: sane interaction between ptrace and job control signals, take#2 Tejun Heo
2010-12-06 16:56 ` [PATCH 01/16] signal: fix SIGCONT notification code Tejun Heo
2010-12-06 16:56 ` [PATCH 02/16] signal: fix CLD_CONTINUED notification target Tejun Heo
2010-12-20 14:58 ` Oleg Nesterov
2010-12-21 16:31 ` Tejun Heo
2010-12-06 16:56 ` [PATCH 03/16] signal: remove superflous try_to_freeze() loop in do_signal_stop() Tejun Heo
2010-12-20 14:59 ` Oleg Nesterov
2010-12-06 16:56 ` [PATCH 04/16] ptrace: kill tracehook_notify_jctl() Tejun Heo
2010-12-20 14:59 ` Oleg Nesterov
2010-12-21 17:00 ` Tejun Heo
2010-12-06 16:56 ` [PATCH 05/16] ptrace: add @why to ptrace_stop() Tejun Heo
2010-12-06 16:56 ` [PATCH 06/16] signal: fix premature completion of group stop when interfered by ptrace Tejun Heo
2010-12-20 15:00 ` Oleg Nesterov
2010-12-21 17:04 ` Tejun Heo
2010-12-06 16:56 ` [PATCH 07/16] signal: use GROUP_STOP_PENDING to stop once for a single group stop Tejun Heo
2010-12-06 16:56 ` [PATCH 08/16] ptrace: participate in group stop from ptrace_stop() iff the task is trapping for " Tejun Heo
2010-12-06 16:56 ` [PATCH 09/16] ptrace: make do_signal_stop() use ptrace_stop() if the task is being ptraced Tejun Heo
2010-12-23 12:26 ` Oleg Nesterov
2010-12-23 13:53 ` Tejun Heo
2010-12-23 16:06 ` Oleg Nesterov
2010-12-23 16:33 ` Tejun Heo
2011-01-17 22:09 ` Roland McGrath
2011-01-27 13:56 ` Tejun Heo
2011-01-28 20:30 ` Roland McGrath
2011-01-31 14:39 ` Tejun Heo
2010-12-06 16:56 ` [PATCH 10/16] ptrace: clean transitions between TASK_STOPPED and TRACED Tejun Heo
2010-12-20 15:00 ` Oleg Nesterov
2010-12-21 17:31 ` Tejun Heo
2010-12-21 17:32 ` Tejun Heo
2010-12-22 10:54 ` Tejun Heo
2010-12-22 11:39 ` Oleg Nesterov
2010-12-22 15:14 ` Tejun Heo
2010-12-22 16:00 ` Oleg Nesterov
2010-12-22 16:21 ` Tejun Heo
2010-12-06 16:56 ` [PATCH 11/16] signal: prepare for CLD_* notification changes Tejun Heo
2010-12-20 16:21 ` Oleg Nesterov
2010-12-20 16:23 ` Oleg Nesterov
2010-12-21 17:35 ` Tejun Heo
2010-12-06 16:57 ` [PATCH 12/16] ptrace: make group stop notification reliable against ptrace Tejun Heo
2010-12-20 17:34 ` Oleg Nesterov
2010-12-21 17:43 ` Tejun Heo
2010-12-22 11:54 ` Oleg Nesterov
2010-12-22 15:26 ` Tejun Heo
2010-12-22 16:02 ` Oleg Nesterov
2010-12-06 16:57 ` [PATCH 13/16] ptrace: reorganize __ptrace_unlink() and ptrace_untrace() Tejun Heo
2010-12-20 18:15 ` Oleg Nesterov
2010-12-21 17:54 ` Tejun Heo
2010-12-06 16:57 ` [PATCH 14/16] ptrace: make SIGCONT notification reliable against ptrace Tejun Heo
2010-12-20 19:43 ` Oleg Nesterov
2010-12-21 17:48 ` Tejun Heo
2010-12-22 12:16 ` Oleg Nesterov
2010-12-21 17:25 ` Oleg Nesterov
2010-12-22 10:35 ` Tejun Heo
2010-12-06 16:57 ` [PATCH 15/16] ptrace: make sure SIGNAL_NOTIFY_CONT is checked after ptrace_signal() Tejun Heo
2010-12-06 16:57 ` [PATCH 16/16] ptrace: remove the extra wake_up_process() from ptrace_detach() Tejun Heo
2010-12-07 0:10 ` Roland McGrath
2010-12-07 13:43 ` Tejun Heo [this message]
2010-12-21 17:54 ` Oleg Nesterov
2010-12-22 10:36 ` Tejun Heo
2010-12-14 17:36 ` [PATCHSET] ptrace,signal: sane interaction between ptrace and job control signals, take#2 Oleg Nesterov
2010-12-14 17:46 ` Tejun Heo
2010-12-22 15:20 ` Oleg Nesterov
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