From: Kees Cook <keescook@chromium.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Alexey Gladkov <legion@kernel.org>, Kyle Huey <me@kylehuey.com>,
Oleg Nesterov <oleg@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>, Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH 08/13] task_work: Call tracehook_notify_signal from get_signal on all architectures
Date: Thu, 10 Mar 2022 12:00:18 -0800 [thread overview]
Message-ID: <202203101159.67711A1@keescook> (raw)
In-Reply-To: <874k45633f.fsf@email.froward.int.ebiederm.org>
On Thu, Mar 10, 2022 at 01:04:52PM -0600, Eric W. Biederman wrote:
> Kees Cook <keescook@chromium.org> writes:
>
> > On Wed, Mar 09, 2022 at 10:24:49AM -0600, Eric W. Biederman wrote:
> >> Always handle TIF_NOTIFY_SIGNAL in get_signal. With commit 35d0b389f3b2
> >> ("task_work: unconditionally run task_work from get_signal()") always
> >> calling task_wofffffffrk_run all of the work of tracehook_notify_signal is
> >
> > typo: cat on keyboard
> >
> >> already happening except clearing TIF_NOTIFY_SIGNAL.
> >>
> >> Factor clear_notify_signal out of tracehook_notify_signal and use it in
> >> get_signal so that get_signal only needs one call of trask_work_run.
> >
> > typo: trask -> task
> >
> >>
> >> To keep the semantics in sync update xfer_to_guest_mode_work (which
> >> does not call get_signal) to call tracehook_notify_signal if either
> >> _TIF_SIGPENDING or _TIF_NOTIFY_SIGNAL.
>
> First let me say thanks for the close look at this work.
>
> > I see three logical changes in this patch, I think?
> >
> > - creation and use of clear_notify_signal()
> > - removal of handle_signal_work() and removal of
> > arch_do_signal_or_restart() has_signal arg
> > - something with get_signal() I don't understand yet:
> > - why is clear_notify_signal() added?
> > - why is tracehook_notify_signal() removed?
>
>
> The spoiler is the change to get_signal is the logical change.
> The rest of the changes follow from that change. Please see below.
>
> The inline expansion of tracehook_notify_signal in get_signal and
> in it's other two callers in the next change is the only real kernel
> internal api change in this series of changes.
>
> The optimization that was tried with TIF_NOTIFY_SIGNAL and being able to
> only call task_work_run() when TIF_NOTIFY_SIGNAL was set instead of when
> get_signal was called failed, and caused a regression. The removal of
> calling task_work_run from get_signal has been reverted but the rest
> of the change had not been. So this change just removes the rest of
> the failed optimization.
>
> Please see below for my detailed description of the get_signal change.
>
> I hope this helps.
It does! Thanks very much for the additional details.
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2022-03-10 20:00 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
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 [this message]
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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