From: Michael Schmitz <schmitzmic@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>,
Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-Arch <linux-arch@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Kees Cook <keescook@chromium.org>,
Linux API <linux-api@vger.kernel.org>,
linux-m68k <linux-m68k@lists.linux-m68k.org>
Subject: Re: [PATCH 08/17] ptrace/m68k: Stop open coding ptrace_report_syscall
Date: Tue, 11 Jan 2022 14:33:50 +1300 [thread overview]
Message-ID: <acf7b627-2dec-c76c-2aa0-6b4c6addd793@gmail.com> (raw)
In-Reply-To: <CAMuHMdX9nhUQe_jeQCUtXeQgcQ5MBiHpPiRexh86EssoHNtJ3Q@mail.gmail.com>
Hi Geert,
Am 11.01.2022 um 06:54 schrieb Geert Uytterhoeven:
> Hi Al,
>
> CC Michael/m68k,
>
> On Mon, Jan 10, 2022 at 5:20 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>> On Mon, Jan 10, 2022 at 04:26:57PM +0100, Geert Uytterhoeven wrote:
>>> On Mon, Jan 3, 2022 at 10:33 PM Eric W. Biederman <ebiederm@xmission.com> wrote:
>>>> The generic function ptrace_report_syscall does a little more
>>>> than syscall_trace on m68k. The function ptrace_report_syscall
>>>> stops early if PT_TRACED is not set, it sets ptrace_message,
>>>> and returns the result of fatal_signal_pending.
>>>>
>>>> Setting ptrace_message to a passed in value of 0 is effectively not
>>>> setting ptrace_message, making that additional work a noop.
>>>>
>>>> Returning the result of fatal_signal_pending and letting the caller
>>>> ignore the result becomes a noop in this change.
>>>>
>>>> When a process is ptraced, the flag PT_PTRACED is always set in
>>>> current->ptrace. Testing for PT_PTRACED in ptrace_report_syscall is
>>>> just an optimization to fail early if the process is not ptraced.
>>>> Later on in ptrace_notify, ptrace_stop will test current->ptrace under
>>>> tasklist_lock and skip performing any work if the task is not ptraced.
>>>>
>>>> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
>>>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
>>>
>>> As this depends on the removal of a parameter from
>>> ptrace_report_syscall() earlier in this series:
>>> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
>>
>> FWIW, I would suggest taking it a bit further: make syscall_trace_enter()
>> and syscall_trace_leave() in m68k ptrace.c unconditional, replace the
>> calls of syscall_trace() in entry.S with syscall_trace_enter() and
>> syscall_trace_leave() resp. and remove syscall_trace().
>>
>> Geert, do you see any problems with that? The only difference is that
>> current->ptrace_message would be set to 1 for ptrace stop on entry and
>> 2 - on leave. Currently m68k just has it 0 all along.
>>
>> It is user-visible (the whole point is to let the tracer see which
>> stop it is - entry or exit one), so somebody using PTRACE_GETEVENTMSG
>> on syscall stops would start seeing 1 or 2 instead of "0 all along".
>> That's how it works on all other architectures (including m68k-nommu),
>> and I doubt that anything in userland will get broken.
>>
>> Behaviour of PTRACE_GETEVENTMSG for other stops (fork, etc.) remains
>> as-is, of course.
>
> In fact Michael did so in "[PATCH v7 1/2] m68k/kernel - wire up
> syscall_trace_enter/leave for m68k"[1], but that's still stuck...
>
> [1] https://lore.kernel.org/r/1624924520-17567-2-git-send-email-schmitzmic@gmail.com/
That patch (for reasons I never found out) did interact badly with
Christoph Hellwig's 'remove set_fs' patches (and Al's signal fixes which
Christoph's patches are based upon). Caused format errors under memory
stress tests quite reliably, on my 030 hardware.
Probably needs a fresh look - the signal return path got changed by Al's
patches IIRC, and I might have relied on offsets to data on the stack
that are no longer correct with these patches. Or there's a race between
the syscall trap and signal handling when returning from interrupt
context ...
Still school hols over here so I won't have much peace and quiet until
February.
Cheers,
Michael
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
>
next prev parent reply other threads:[~2022-01-11 1:34 UTC|newest]
Thread overview: 193+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 20:17 [PATCH 00/10] Removal of most do_exit calls Eric W. Biederman
2021-12-08 20:25 ` [PATCH 01/10] exit/s390: Remove dead reference to do_exit from copy_thread Eric W. Biederman
2021-12-12 17:48 ` Heiko Carstens
2021-12-13 14:50 ` Eric W. Biederman
2022-01-05 4:25 ` Al Viro
2021-12-08 20:25 ` [PATCH 02/10] exit: Add and use make_task_dead Eric W. Biederman
2022-01-05 5:01 ` Al Viro
2022-01-05 20:46 ` Eric W. Biederman
2022-01-05 21:53 ` Al Viro
2022-01-05 22:51 ` Linus Torvalds
2022-01-05 23:34 ` Al Viro
2021-12-08 20:25 ` [PATCH 03/10] exit: Move oops specific logic from do_exit into make_task_dead Eric W. Biederman
2022-01-05 5:48 ` Al Viro
2022-01-06 7:08 ` Al Viro
2022-01-07 3:42 ` Al Viro
2022-01-07 19:02 ` Eric W. Biederman
2022-01-07 18:59 ` Eric W. Biederman
2022-01-17 8:05 ` Christoph Hellwig
2022-01-17 12:15 ` Heiko Carstens
2022-01-17 13:17 ` Christoph Hellwig
2022-01-17 13:24 ` Arnd Bergmann
2022-01-17 13:27 ` [PATCH] microblaze: remove CONFIG_SET_FS Arnd Bergmann
2022-02-09 13:50 ` Michal Simek
2022-02-09 13:52 ` Christoph Hellwig
2022-02-09 14:03 ` Michal Simek
2022-02-09 14:40 ` Arnd Bergmann
2022-02-09 14:44 ` Michal Simek
2022-02-09 14:54 ` Arnd Bergmann
2022-02-09 23:31 ` Stafford Horne
2022-02-11 0:17 ` Stafford Horne
2022-02-11 16:59 ` Arnd Bergmann
2022-02-11 17:46 ` Linus Torvalds
2022-02-11 20:57 ` Arnd Bergmann
2022-02-11 21:10 ` Eric W. Biederman
2022-02-11 22:21 ` Stafford Horne
2022-02-14 7:41 ` Christoph Hellwig
2022-02-14 7:50 ` Christoph Hellwig
2022-02-14 16:20 ` Arnd Bergmann
2021-12-08 20:25 ` [PATCH 04/10] exit: Stop poorly open coding do_task_dead in make_task_dead Eric W. Biederman
2022-01-05 5:58 ` Al Viro
2022-01-05 22:33 ` Eric W. Biederman
2021-12-08 20:25 ` [PATCH 05/10] exit: Stop exporting do_exit Eric W. Biederman
2022-01-05 6:02 ` Al Viro
2022-01-05 22:36 ` Eric W. Biederman
2021-12-08 20:25 ` [PATCH 06/10] exit: Implement kthread_exit Eric W. Biederman
2022-01-07 2:27 ` Al Viro
2022-01-08 18:35 ` Eric W. Biederman
2022-01-08 22:44 ` David Laight
2022-01-10 15:00 ` Eric W. Biederman
2022-01-09 3:27 ` Al Viro
2022-01-10 15:05 ` Eric W. Biederman
2021-12-08 20:25 ` [PATCH 07/10] exit: Rename module_put_and_exit to module_put_and_kthread_exit Eric W. Biederman
2021-12-08 20:25 ` [PATCH 08/10] exit: Rename complete_and_exit to kthread_complete_and_exit Eric W. Biederman
2021-12-08 20:25 ` [PATCH 09/10] kthread: Ensure struct kthread is present for all kthreads Eric W. Biederman
2021-12-22 18:19 ` Nathan Chancellor
2021-12-22 18:30 ` Eric W. Biederman
2021-12-22 18:46 ` Nathan Chancellor
2021-12-22 23:22 ` Eric W. Biederman
2021-12-23 0:37 ` Nathan Chancellor
2021-12-23 1:44 ` Linus Torvalds
2021-12-23 3:34 ` Eric W. Biederman
2021-12-23 5:19 ` [PATCH] kthread: Generalize pf_io_worker so it can point to struct kthread Eric W. Biederman
2021-12-23 17:20 ` Linus Torvalds
2022-01-07 3:59 ` [PATCH 09/10] kthread: Ensure struct kthread is present for all kthreads Al Viro
2022-01-08 18:20 ` Eric W. Biederman
2021-12-08 20:25 ` [PATCH 10/10] exit/kthread: Move the exit code for kernel threads into struct kthread Eric W. Biederman
2022-01-07 3:22 ` Al Viro
2021-12-13 22:50 ` [PATCH 0/8] signal: Cleanup of the signal->flags Eric W. Biederman
2022-01-03 21:30 ` [PATCH 00/17] exit: Making task exiting a first class concept Eric W. Biederman
2022-01-03 21:32 ` [PATCH 01/17] exit: Remove profile_task_exit & profile_munmap Eric W. Biederman
2022-01-04 7:38 ` Christoph Hellwig
2022-01-07 3:48 ` Al Viro
2022-01-08 16:10 ` Eric W. Biederman
2022-01-03 21:32 ` [PATCH 02/17] exit: Coredumps reach do_group_exit Eric W. Biederman
2022-01-03 21:32 ` [PATCH 03/17] exit: Fix the exit_code for wait_task_zombie Eric W. Biederman
2022-01-03 21:32 ` [PATCH 04/17] exit: Use the correct exit_code in /proc/<pid>/stat Eric W. Biederman
2022-01-03 21:33 ` [PATCH 05/17] taskstats: Cleanup the use of task->exit_code Eric W. Biederman
2022-01-03 21:33 ` [PATCH 06/17] ptrace: Remove second setting of PT_SEIZED in ptrace_attach Eric W. Biederman
2022-01-03 21:33 ` [PATCH 07/17] ptrace: Remove unused regs argument from ptrace_report_syscall Eric W. Biederman
2022-01-03 21:33 ` [PATCH 08/17] ptrace/m68k: Stop open coding ptrace_report_syscall Eric W. Biederman
2022-01-10 15:26 ` Geert Uytterhoeven
2022-01-10 16:20 ` Al Viro
2022-01-10 16:25 ` Al Viro
2022-01-10 17:54 ` Geert Uytterhoeven
2022-01-10 20:37 ` Al Viro
2022-01-10 21:18 ` Eric W. Biederman
2022-01-11 1:33 ` Michael Schmitz [this message]
2022-01-11 22:42 ` Finn Thain
2022-01-12 0:20 ` Michael Schmitz
2022-01-12 3:32 ` Finn Thain
2022-01-12 7:54 ` Michael Schmitz
2022-01-12 7:55 ` Geert Uytterhoeven
2022-01-12 8:05 ` Michael Schmitz
2022-01-03 21:33 ` [PATCH 09/17] ptrace: Move setting/clearing ptrace_message into ptrace_stop Eric W. Biederman
2022-01-03 21:33 ` [PATCH 10/17] ptrace: Return the signal to continue with from ptrace_stop Eric W. Biederman
2022-01-03 21:33 ` [PATCH 11/17] ptrace: Separate task->ptrace_code out from task->exit_code Eric W. Biederman
2022-01-03 21:33 ` [PATCH 12/17] signal: Compute the process exit_code in get_signal Eric W. Biederman
2022-01-03 21:33 ` [PATCH 13/17] signal: Make individual tasks exiting a first class concept Eric W. Biederman
2022-01-03 21:33 ` [PATCH 14/17] signal: Remove zap_other_threads Eric W. Biederman
2022-01-03 21:33 ` [PATCH 15/17] signal: Add JOBCTL_WILL_EXIT to mark exiting tasks Eric W. Biederman
2022-01-03 21:33 ` [PATCH 16/17] signal: Record the exit_code when an exit is scheduled Eric W. Biederman
2022-01-03 21:33 ` [PATCH 17/17] signal: Always set SIGNAL_GROUP_EXIT on process exit Eric W. Biederman
2022-03-09 0:13 ` [PATCH 00/13] Removing tracehook.h Eric W. Biederman
2022-03-09 16:24 ` [PATCH 01/13] ptrace: Move ptrace_report_syscall into ptrace.h Eric W. Biederman
2022-03-09 22:19 ` Kees Cook
2022-03-09 16:24 ` [PATCH 02/13] ptrace/arm: Rename tracehook_report_syscall report_syscall Eric W. Biederman
2022-03-09 22:20 ` Kees Cook
2022-03-09 16:24 ` [PATCH 03/13] ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h Eric W. Biederman
2022-03-09 22:26 ` Kees Cook
2022-03-09 16:24 ` [PATCH 04/13] ptrace: Remove arch_syscall_{enter,exit}_tracehook Eric W. Biederman
2022-03-09 22:29 ` Kees Cook
2022-03-09 16:24 ` [PATCH 05/13] ptrace: Remove tracehook_signal_handler Eric W. Biederman
2022-03-09 22:29 ` Kees Cook
2022-03-09 16:24 ` [PATCH 06/13] task_work: Remove unnecessary include from posix_timers.h Eric W. Biederman
2022-03-09 22:30 ` Kees Cook
2022-03-09 16:24 ` [PATCH 07/13] task_work: Introduce task_work_pending Eric W. Biederman
2022-03-09 21:05 ` Jens Axboe
2022-03-09 23:24 ` Eric W. Biederman
2022-03-09 23:26 ` Jens Axboe
2022-03-09 22:31 ` Kees Cook
2022-03-09 16:24 ` [PATCH 08/13] task_work: Call tracehook_notify_signal from get_signal on all architectures Eric W. Biederman
2022-03-10 5:57 ` Kees Cook
2022-03-10 19:04 ` Eric W. Biederman
2022-03-10 20:00 ` Kees Cook
2022-03-09 16:24 ` [PATCH 09/13] task_work: Decouple TIF_NOTIFY_SIGNAL and task_work Eric W. Biederman
2022-03-09 22:36 ` Kees Cook
2022-03-09 16:24 ` [PATCH 10/13] signal: Move set_notify_signal and clear_notify_signal into sched/signal.h Eric W. Biederman
2022-03-09 22:36 ` Kees Cook
2022-03-09 16:24 ` [PATCH 11/13] resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume Eric W. Biederman
2022-03-09 22:39 ` Kees Cook
2022-03-09 16:24 ` [PATCH 12/13] resume_user_mode: Move to resume_user_mode.h Eric W. Biederman
2022-03-09 22:54 ` Kees Cook
2022-03-09 16:24 ` [PATCH 13/13] tracehook: Remove tracehook.h Eric W. Biederman
2022-03-09 22:55 ` Kees Cook
2022-03-09 21:05 ` [PATCH 00/13] Removing tracehook.h Jens Axboe
2022-03-15 23:18 ` [PATCH 0/2] ptrace: Making the ptrace changes atomic Eric W. Biederman
2022-03-15 23:21 ` [PATCH 1/2] ptrace: Move setting/clearing ptrace_message into ptrace_stop Eric W. Biederman
2022-03-17 17:46 ` Oleg Nesterov
2022-03-17 19:10 ` Kees Cook
2022-03-18 14:44 ` Eric W. Biederman
2022-03-18 17:20 ` Kees Cook
2022-03-15 23:22 ` [PATCH 2/2] ptrace: Return the signal to continue with from ptrace_stop Eric W. Biederman
2022-03-17 18:08 ` Oleg Nesterov
2022-03-17 18:31 ` Eric W. Biederman
2022-03-18 19:43 ` Oleg Nesterov
2022-03-18 14:40 ` Eric W. Biederman
2022-03-17 19:13 ` Kees Cook
2022-03-18 14:52 ` Eric W. Biederman
2022-03-18 17:28 ` Kees Cook
2022-03-28 23:56 ` [GIT PULL] ptrace: Cleanups for v5.18 Eric W. Biederman
2022-03-29 0:03 ` Jens Axboe
2022-03-29 0:33 ` Linus Torvalds
2022-03-29 0:53 ` Stephen Rothwell
2022-03-29 0:58 ` Linus Torvalds
2022-03-29 3:37 ` Eric W. Biederman
2022-03-29 4:49 ` Linus Torvalds
2022-03-29 5:20 ` Linus Torvalds
2022-03-29 0:35 ` pr-tracker-bot
2022-03-09 0:15 ` [PATCH 00/13] Removing tracehook.h Eric W. Biederman
2022-03-09 20:58 ` Linus Torvalds
2021-12-13 22:53 ` [PATCH 1/8] signal: Make SIGKILL during coredumps an explicit special case Eric W. Biederman
2022-01-04 6:30 ` Dmitry Osipenko
2022-01-04 16:18 ` Eric W. Biederman
2022-01-05 19:58 ` Eric W. Biederman
2022-01-05 21:39 ` Dmitry Osipenko
2022-01-08 18:13 ` Eric W. Biederman
2022-01-08 18:15 ` [PATCH 1/2] signal: Have prepare_signal detect coredumps using signal->core_state Eric W. Biederman
2022-01-08 18:15 ` [PATCH 2/2] signal: Make coredump handling explicit in complete_signal Eric W. Biederman
2022-01-11 8:59 ` [PATCH 1/8] signal: Make SIGKILL during coredumps an explicit special case Dmitry Osipenko
2022-01-11 17:20 ` Eric W. Biederman
2022-01-18 17:30 ` Dmitry Osipenko
2022-01-18 17:52 ` Eric W. Biederman
2022-01-18 18:01 ` Dmitry Osipenko
2022-01-04 18:44 ` Linus Torvalds
2022-01-04 19:47 ` Eric W. Biederman
2022-01-08 19:13 ` Heiko Carstens
[not found] ` <87ilurwjju.fsf@email.froward.int.ebiederm.org>
[not found] ` <87o84juwhg.fsf@email.froward.int.ebiederm.org>
2022-01-10 23:00 ` Olivier Langlois
2022-01-11 17:28 ` Eric W. Biederman
2022-01-11 18:51 ` Eric W. Biederman
2022-01-11 19:19 ` Linus Torvalds
2022-01-15 0:12 ` Eric W. Biederman
2022-01-15 19:23 ` Olivier Langlois
2022-01-17 16:09 ` Eric W. Biederman
2022-01-17 18:46 ` io_uring truncating coredumps Eric W. Biederman
2022-01-18 4:23 ` Linus Torvalds
2022-01-26 15:06 ` [PATCH 1/8] signal: Make SIGKILL during coredumps an explicit special case Olivier Langlois
2021-12-13 22:53 ` [PATCH 2/8] signal: Drop signals received after a fatal signal has been processed Eric W. Biederman
2021-12-13 22:53 ` [PATCH 3/8] signal: Have the oom killer detect coredumps using signal->core_state Eric W. Biederman
2021-12-13 22:53 ` [PATCH 4/8] signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process Eric W. Biederman
2021-12-13 22:53 ` [PATCH 5/8] signal: Remove SIGNAL_GROUP_COREDUMP Eric W. Biederman
2021-12-13 22:53 ` [PATCH 6/8] coredump: Stop setting signal->group_exit_task Eric W. Biederman
2021-12-13 22:53 ` [PATCH 7/8] signal: Rename group_exit_task group_exec_task Eric W. Biederman
2021-12-13 22:53 ` [PATCH 8/8] signal: Remove the helper signal_group_exit Eric W. Biederman
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