From: "Eric W. Biederman" <ebiederm@xmission.com>
To: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
linux-kernel@vger.kernel.org, mingo@kernel.org,
bigeasy@linutronix.de, Peter Zijlstra <peterz@infradead.org>,
Jann Horn <jannh@google.com>, Kees Cook <keescook@chromium.org>,
"Robert O'Callahan" <roc@pernos.co>, Kyle Huey <khuey@pernos.co>,
Keno Fischer <keno@juliacomputing.com>
Subject: Re: [PATCH 0/3] ptrace: Stop supporting SIGKILL for PTRACE_EVENT_EXIT
Date: Thu, 23 Jun 2022 16:55:05 -0500 [thread overview]
Message-ID: <87ilor9hae.fsf@email.froward.int.ebiederm.org> (raw)
In-Reply-To: <YrSC8AxEV24IgSbm@li-4a3a4a4c-28e5-11b2-a85c-a8d192c6f089.ibm.com> (Alexander Gordeev's message of "Thu, 23 Jun 2022 17:12:48 +0200")
Alexander Gordeev <agordeev@linux.ibm.com> writes:
> On Wed, Jun 22, 2022 at 11:43:37AM -0500, Eric W. Biederman wrote:
>> Recently I had a conversation where it was pointed out to me that
>> SIGKILL sent to a tracee stropped in PTRACE_EVENT_EXIT is quite
>> difficult for a tracer to handle.
>>
>> Keeping SIGKILL working for anything after the process has been killed
>> is also a real pain from an implementation point of view.
>>
>> So I am attempting to remove this wart in the userspace API and see
>> if anyone cares.
>
> Hi Eric,
>
> With this series s390 hits the warning exactly same way. Is that expected?
Yes. I was working on this before I got your mysterious bug report. I
included you because I am including everyone I know who deals with the
userspace side of this since I am very deliberately changing the user
visible behavior of PTRACE_EVENT_EXIT.
I am going to start seeing if I can find any possible explanation for
your regression report. Since I don't have much to go on I expect I
will have to revert the last change in my ptrace_stop series that
apparently triggers the WARN_ON you reported. I really would have
expected the WARN_ON to be triggered in the patch in which it was
introduced, not the final patch in the series.
To the best of my knowledge changing PTRACE_EVENT_EXIT is both desirable
from a userspace semantics standpoint and from a kernel implementation
standpoint. If someone knows any differently and depends upon sending
SIGKILL to processes in PTRACE_EVENT_EXIT to steal the process away from
the tracer I would love to hear about that case.
Eric
next prev parent reply other threads:[~2022-06-23 21:55 UTC|newest]
Thread overview: 240+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-21 15:02 [PATCH v2 0/5] ptrace-vs-PREEMPT_RT and freezer rewrite Peter Zijlstra
2022-04-21 15:02 ` [PATCH v2 1/5] sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state Peter Zijlstra
2022-04-26 23:34 ` Eric W. Biederman
2022-04-28 10:00 ` Peter Zijlstra
2022-04-21 15:02 ` [PATCH v2 2/5] sched,ptrace: Fix ptrace_check_attach() vs PREEMPT_RT Peter Zijlstra
2022-04-21 18:23 ` Oleg Nesterov
2022-04-21 19:58 ` Peter Zijlstra
2022-04-21 18:40 ` Eric W. Biederman
2022-04-26 22:50 ` [PATCH 0/9] ptrace: cleaning up ptrace_stop Eric W. Biederman
2022-04-26 22:52 ` [PATCH 1/9] signal: Rename send_signal send_signal_locked Eric W. Biederman
2022-04-28 10:27 ` Peter Zijlstra
2022-04-26 22:52 ` [PATCH 2/9] signal: Replace __group_send_sig_info with send_signal_locked Eric W. Biederman
2022-04-26 22:52 ` [PATCH 3/9] ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP Eric W. Biederman
2022-04-27 7:10 ` Johannes Berg
2022-04-27 13:50 ` Eric W. Biederman
2022-04-26 22:52 ` [PATCH 4/9] ptrace/xtensa: Replace PT_SINGLESTEP " Eric W. Biederman
2022-04-26 23:33 ` Max Filippov
2022-04-26 22:52 ` [PATCH 5/9] signal: Protect parent child relationships by childs siglock Eric W. Biederman
2022-04-27 6:40 ` Sebastian Andrzej Siewior
2022-04-27 13:35 ` Eric W. Biederman
2022-04-26 22:52 ` [PATCH 6/9] signal: Always call do_notify_parent_cldstop with siglock held Eric W. Biederman
2022-04-27 14:10 ` Oleg Nesterov
2022-04-27 14:20 ` Eric W. Biederman
2022-04-27 14:43 ` Oleg Nesterov
2022-04-27 14:47 ` Eric W. Biederman
2022-04-28 17:44 ` Peter Zijlstra
2022-04-28 18:22 ` Oleg Nesterov
2022-04-28 18:37 ` Eric W. Biederman
2022-04-28 20:49 ` Eric W. Biederman
2022-04-28 22:19 ` Peter Zijlstra
2022-04-27 14:56 ` Oleg Nesterov
2022-04-27 15:00 ` Oleg Nesterov
2022-04-27 21:52 ` Eric W. Biederman
2022-04-28 10:38 ` Peter Zijlstra
2022-04-26 22:52 ` [PATCH 7/9] ptrace: Simplify the wait_task_inactive call in ptrace_check_attach Eric W. Biederman
2022-04-27 13:42 ` Eric W. Biederman
2022-04-27 14:27 ` Eric W. Biederman
2022-04-27 15:14 ` Oleg Nesterov
2022-04-28 10:42 ` Peter Zijlstra
2022-04-28 11:19 ` Oleg Nesterov
2022-04-28 13:54 ` Peter Zijlstra
2022-04-28 14:57 ` Oleg Nesterov
2022-04-28 16:09 ` Peter Zijlstra
2022-04-28 16:19 ` Oleg Nesterov
2022-04-26 22:52 ` [PATCH 8/9] ptrace: Use siglock instead of tasklist_lock " Eric W. Biederman
2022-04-27 15:20 ` Oleg Nesterov
2022-04-26 22:52 ` [PATCH 9/9] ptrace: Don't change __state Eric W. Biederman
2022-04-27 15:41 ` Oleg Nesterov
2022-04-27 22:35 ` Eric W. Biederman
2022-04-27 16:09 ` Oleg Nesterov
2022-04-27 16:33 ` Eric W. Biederman
2022-04-27 17:18 ` Oleg Nesterov
2022-04-27 17:21 ` Oleg Nesterov
2022-04-27 17:31 ` Eric W. Biederman
2022-04-27 23:05 ` Eric W. Biederman
2022-04-28 15:11 ` Oleg Nesterov
2022-04-28 16:50 ` Eric W. Biederman
2022-04-28 18:53 ` Oleg Nesterov
2022-04-28 10:07 ` [PATCH 0/9] ptrace: cleaning up ptrace_stop Peter Zijlstra
2022-04-29 21:46 ` [PATCH 0/12] " Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 01/12] signal: Rename send_signal send_signal_locked Eric W. Biederman
2022-05-02 7:50 ` Sebastian Andrzej Siewior
2022-04-29 21:48 ` [PATCH v2 02/12] signal: Replace __group_send_sig_info with send_signal_locked Eric W. Biederman
2022-05-02 7:58 ` Sebastian Andrzej Siewior
2022-04-29 21:48 ` [PATCH v2 03/12] ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 04/12] ptrace/xtensa: Replace PT_SINGLESTEP " Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 05/12] signal: Use lockdep_assert_held instead of assert_spin_locked Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 06/12] ptrace: Reimplement PTRACE_KILL by always sending SIGKILL Eric W. Biederman
2022-05-02 14:37 ` Oleg Nesterov
2022-05-03 19:36 ` Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 07/12] ptrace: Don't change __state Eric W. Biederman
2022-04-29 22:27 ` Peter Zijlstra
2022-05-02 8:59 ` Sebastian Andrzej Siewior
2022-05-02 15:39 ` Oleg Nesterov
2022-05-02 16:35 ` Eric W. Biederman
2022-05-03 13:41 ` Oleg Nesterov
2022-05-03 20:45 ` Eric W. Biederman
2022-05-04 14:02 ` Oleg Nesterov
2022-05-04 17:37 ` Eric W. Biederman
2022-05-04 18:28 ` Eric W. Biederman
2022-05-02 15:47 ` Oleg Nesterov
2022-04-29 21:48 ` [PATCH v2 08/12] ptrace: Remove arch_ptrace_attach Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 09/12] ptrace: Always take siglock in ptrace_resume Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 10/12] ptrace: Only return signr from ptrace_stop if it was provided Eric W. Biederman
2022-05-02 10:08 ` Sebastian Andrzej Siewior
2022-04-29 21:48 ` [PATCH v2 11/12] ptrace: Always call schedule in ptrace_stop Eric W. Biederman
2022-04-29 21:48 ` [PATCH v2 12/12] sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state Eric W. Biederman
2022-05-02 10:18 ` Sebastian Andrzej Siewior
2022-05-02 13:38 ` [PATCH 0/12] ptrace: cleaning up ptrace_stop Sebastian Andrzej Siewior
2022-05-04 22:39 ` [PATCH v3 0/11] " Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 01/11] signal: Rename send_signal send_signal_locked Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 02/11] signal: Replace __group_send_sig_info with send_signal_locked Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 03/11] ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 04/11] ptrace/xtensa: Replace PT_SINGLESTEP " Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 05/11] ptrace: Remove arch_ptrace_attach Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 06/11] signal: Use lockdep_assert_held instead of assert_spin_locked Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 07/11] ptrace: Reimplement PTRACE_KILL by always sending SIGKILL Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 08/11] ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs Eric W. Biederman
2022-05-05 14:57 ` Oleg Nesterov
2022-05-05 16:59 ` Eric W. Biederman
2022-05-05 15:01 ` Oleg Nesterov
2022-05-05 17:21 ` Eric W. Biederman
2022-05-05 17:27 ` Oleg Nesterov
2022-05-05 15:28 ` Oleg Nesterov
2022-05-05 17:53 ` Eric W. Biederman
2022-05-05 18:10 ` Oleg Nesterov
2022-05-04 22:40 ` [PATCH v3 09/11] ptrace: Don't change __state Eric W. Biederman
2022-05-05 12:50 ` Sebastian Andrzej Siewior
2022-05-05 16:48 ` Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 10/11] ptrace: Always take siglock in ptrace_resume Eric W. Biederman
2022-05-04 22:40 ` [PATCH v3 11/11] sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state Eric W. Biederman
2022-05-05 18:25 ` [PATCH v4 0/12] ptrace: cleaning up ptrace_stop Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 01/12] signal: Rename send_signal send_signal_locked Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 02/12] signal: Replace __group_send_sig_info with send_signal_locked Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 03/12] ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 04/12] ptrace/xtensa: Replace PT_SINGLESTEP " Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 05/12] ptrace: Remove arch_ptrace_attach Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 06/12] signal: Use lockdep_assert_held instead of assert_spin_locked Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 07/12] ptrace: Reimplement PTRACE_KILL by always sending SIGKILL Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 08/12] ptrace: Document that wait_task_inactive can't fail Eric W. Biederman
2022-05-06 6:55 ` Sebastian Andrzej Siewior
2022-05-05 18:26 ` [PATCH v4 09/12] ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 10/12] ptrace: Don't change __state Eric W. Biederman
2022-05-06 15:09 ` Oleg Nesterov
2022-05-06 19:42 ` Eric W. Biederman
2022-05-10 14:23 ` Oleg Nesterov
2022-05-10 15:17 ` Eric W. Biederman
2022-05-10 15:34 ` Oleg Nesterov
2022-05-05 18:26 ` [PATCH v4 11/12] ptrace: Always take siglock in ptrace_resume Eric W. Biederman
2022-05-05 18:26 ` [PATCH v4 12/12] sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state Eric W. Biederman
2022-06-21 13:00 ` Alexander Gordeev
2022-06-21 14:02 ` Eric W. Biederman
2022-06-21 15:15 ` Alexander Gordeev
2022-06-21 17:47 ` Eric W. Biederman
2022-06-25 16:34 ` Eric W. Biederman
2022-06-28 18:36 ` Alexander Gordeev
2022-06-28 22:42 ` Eric W. Biederman
2022-06-28 22:48 ` Steven Rostedt
2022-06-29 3:39 ` Eric W. Biederman
2022-06-29 20:25 ` Alexander Gordeev
2022-07-05 15:44 ` Peter Zijlstra
2022-07-06 6:56 ` Alexander Gordeev
2022-06-28 23:15 ` Steven Rostedt
2022-07-05 13:47 ` Sven Schnelle
2022-07-05 17:28 ` Sven Schnelle
2022-07-05 19:25 ` Peter Zijlstra
2022-07-06 7:58 ` Sven Schnelle
2022-07-06 8:59 ` Peter Zijlstra
2022-07-06 9:27 ` Sven Schnelle
2022-07-06 10:11 ` Peter Zijlstra
2022-05-06 14:14 ` [PATCH v4 0/12] ptrace: cleaning up ptrace_stop Oleg Nesterov
2022-05-06 14:38 ` Eric W. Biederman
2022-05-06 21:26 ` Kees Cook
2022-05-06 21:59 ` Eric W. Biederman
2022-05-10 14:11 ` Oleg Nesterov
2022-05-10 14:26 ` Eric W. Biederman
2022-05-10 14:45 ` Sebastian Andrzej Siewior
2022-05-10 15:18 ` Eric W. Biederman
2022-05-11 20:00 ` Eric W. Biederman
2022-05-18 22:49 ` [PATCH 00/16] ptrace: cleanups and calling do_cldstop with only siglock Eric W. Biederman
2022-05-18 22:53 ` [PATCH 01/16] signal/alpha: Remove unused definition of TASK_REAL_PARENT Eric W. Biederman
2022-05-18 22:53 ` [PATCH 02/16] signal/ia64: Remove unused definition of IA64_TASK_REAL_PARENT_OFFSET Eric W. Biederman
2022-05-18 22:53 ` [PATCH 03/16] kdb: Use real_parent when displaying a list of processes Eric W. Biederman
2022-05-19 7:56 ` Peter Zijlstra
2022-05-19 18:06 ` Eric W. Biederman
2022-05-19 20:52 ` Doug Anderson
2022-05-19 23:48 ` Eric W. Biederman
2022-05-20 23:01 ` Doug Anderson
2022-05-18 22:53 ` [PATCH 04/16] powerpc/xmon: " Eric W. Biederman
2022-05-18 22:53 ` [PATCH 05/16] ptrace: Remove dead code from __ptrace_detach Eric W. Biederman
2022-05-24 11:42 ` Oleg Nesterov
2022-05-25 14:33 ` Oleg Nesterov
2022-06-06 16:06 ` Eric W. Biederman
2022-05-18 22:53 ` [PATCH 06/16] ptrace: Remove unnecessary locking in ptrace_(get|set)siginfo Eric W. Biederman
2022-05-24 13:25 ` Oleg Nesterov
2022-05-18 22:53 ` [PATCH 07/16] signal: Wake up the designated parent Eric W. Biederman
2022-05-24 13:25 ` Oleg Nesterov
2022-05-24 16:28 ` Oleg Nesterov
2022-05-25 14:28 ` Oleg Nesterov
2022-06-06 22:10 ` Eric W. Biederman
2022-06-07 15:26 ` Oleg Nesterov
2022-05-18 22:53 ` [PATCH 08/16] ptrace: Only populate last_siginfo from ptrace Eric W. Biederman
2022-05-24 15:27 ` Oleg Nesterov
2022-06-06 22:16 ` Eric W. Biederman
2022-06-07 15:29 ` Oleg Nesterov
2022-05-18 22:53 ` [PATCH 09/16] ptrace: In ptrace_setsiginfo deal with invalid si_signo Eric W. Biederman
2022-05-18 22:53 ` [PATCH 10/16] ptrace: In ptrace_signal look at what the debugger did with siginfo Eric W. Biederman
2022-05-18 22:53 ` [PATCH 11/16] ptrace: Use si_sino as the signal number to resume with Eric W. Biederman
2022-05-18 22:53 ` [PATCH 12/16] ptrace: Stop protecting ptrace_set_signr with tasklist_lock Eric W. Biederman
2022-05-18 22:53 ` [PATCH 13/16] ptrace: Document why ptrace_setoptions does not need a lock Eric W. Biederman
2022-05-18 22:53 ` [PATCH 14/16] signal: Protect parent child relationships by childs siglock Eric W. Biederman
2022-05-18 22:53 ` [PATCH 15/16] ptrace: Use siglock instead of tasklist_lock in ptrace_check_attach Eric W. Biederman
2022-05-18 22:53 ` [PATCH 16/16] signal: Always call do_notify_parent_cldstop with siglock held Eric W. Biederman
2022-05-20 16:19 ` kernel test robot
[not found] ` <CALWUPBdFDLuT7JaNGSJ_UXbHf8y9uKdC-SkAqzd=FQC0MX4nNQ@mail.gmail.com>
2022-05-19 6:19 ` [PATCH 00/16] ptrace: cleanups and calling do_cldstop with only siglock Sebastian Andrzej Siewior
2022-05-19 18:05 ` Eric W. Biederman
2022-05-20 5:24 ` Kyle Huey
2022-06-06 16:12 ` Eric W. Biederman
2022-06-09 19:59 ` Kyle Huey
2022-05-20 7:33 ` Sebastian Andrzej Siewior
2022-05-20 19:32 ` Eric W. Biederman
2022-05-20 19:58 ` Peter Zijlstra
2022-05-20 9:19 ` Sebastian Andrzej Siewior
2022-06-22 16:43 ` [PATCH 0/3] ptrace: Stop supporting SIGKILL for PTRACE_EVENT_EXIT Eric W. Biederman
2022-06-22 16:45 ` [PATCH 1/3] signal: Ensure SIGNAL_GROUP_EXIT gets set in do_group_exit Eric W. Biederman
2022-06-22 16:46 ` [PATCH 2/3] signal: Guarantee that SIGNAL_GROUP_EXIT is set on process exit Eric W. Biederman
2022-06-23 7:49 ` kernel test robot
2022-06-22 16:47 ` [PATCH 3/3] signal: Drop signals received after a fatal signal has been processed Eric W. Biederman
2022-06-23 15:12 ` [PATCH 0/3] ptrace: Stop supporting SIGKILL for PTRACE_EVENT_EXIT Alexander Gordeev
2022-06-23 21:55 ` Eric W. Biederman [this message]
2022-07-08 22:25 ` Eric W. Biederman
2022-07-08 23:22 ` Keno Fischer
2022-07-12 20:03 ` Eric W. Biederman
2022-07-16 21:29 ` Eric W. Biederman
2022-07-16 23:21 ` Kyle Huey
2022-04-25 14:35 ` [PATCH v2 2/5] sched,ptrace: Fix ptrace_check_attach() vs PREEMPT_RT Oleg Nesterov
2022-04-25 18:33 ` Peter Zijlstra
2022-04-26 0:38 ` Eric W. Biederman
2022-04-26 5:51 ` Oleg Nesterov
2022-04-26 17:19 ` Eric W. Biederman
2022-04-26 18:11 ` Oleg Nesterov
2022-04-25 17:47 ` Oleg Nesterov
2022-04-27 0:24 ` Eric W. Biederman
2022-04-28 20:29 ` Peter Zijlstra
2022-04-28 20:59 ` Oleg Nesterov
2022-04-28 22:21 ` Peter Zijlstra
2022-04-28 22:50 ` Oleg Nesterov
2022-04-27 15:53 ` Oleg Nesterov
2022-04-27 21:57 ` Eric W. Biederman
2022-04-21 15:02 ` [PATCH v2 3/5] freezer: Have {,un}lock_system_sleep() save/restore flags Peter Zijlstra
2022-04-21 15:02 ` [PATCH v2 4/5] freezer,umh: Clean up freezer/initrd interaction Peter Zijlstra
2022-04-21 15:02 ` [PATCH v2 5/5] freezer,sched: Rewrite core freezer logic Peter Zijlstra
2022-04-21 17:26 ` Eric W. Biederman
2022-04-21 17:57 ` Oleg Nesterov
2022-04-21 19:55 ` Peter Zijlstra
2022-04-21 20:07 ` Peter Zijlstra
2022-04-22 15:52 ` Eric W. Biederman
2022-04-22 17:43 ` [PATCH v2 0/5] ptrace-vs-PREEMPT_RT and freezer rewrite Sebastian Andrzej Siewior
2022-04-22 19:15 ` Eric W. Biederman
2022-04-22 21:13 ` Sebastian Andrzej Siewior
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=87ilor9hae.fsf@email.froward.int.ebiederm.org \
--to=ebiederm@xmission.com \
--cc=agordeev@linux.ibm.com \
--cc=bigeasy@linutronix.de \
--cc=jannh@google.com \
--cc=keescook@chromium.org \
--cc=keno@juliacomputing.com \
--cc=khuey@pernos.co \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=roc@pernos.co \
/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).