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From: Al Viro <viro@zeniv.linux.org.uk>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Alexey Gladkov <legion@kernel.org>, Kyle Huey <me@kylehuey.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Chris Zankel <chris@zankel.net>,
	Max Filippov <jcmvbkbc@gmail.com>
Subject: Re: [PATCH 02/10] exit: Add and use make_task_dead.
Date: Wed, 5 Jan 2022 21:53:27 +0000	[thread overview]
Message-ID: <YdYTV9gQEPxssuZe@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <871r1l9ai5.fsf@email.froward.int.ebiederm.org>

On Wed, Jan 05, 2022 at 02:46:10PM -0600, Eric W. Biederman wrote:
> Al Viro <viro@zeniv.linux.org.uk> writes:
> 
> > On Wed, Dec 08, 2021 at 02:25:24PM -0600, Eric W. Biederman wrote:
> >> There are two big uses of do_exit.  The first is it's design use to be
> >> the guts of the exit(2) system call.  The second use is to terminate
> >> a task after something catastrophic has happened like a NULL pointer
> >> in kernel code.
> >> 
> >> Add a function make_task_dead that is initialy exactly the same as
> >> do_exit to cover the cases where do_exit is called to handle
> >> catastrophic failure.  In time this can probably be reduced to just a
> >> light wrapper around do_task_dead. For now keep it exactly the same so
> >> that there will be no behavioral differences introducing this new
> >> concept.
> >> 
> >> Replace all of the uses of do_exit that use it for catastraphic
> >> task cleanup with make_task_dead to make it clear what the code
> >> is doing.
> >> 
> >> As part of this rename rewind_stack_do_exit
> >> rewind_stack_and_make_dead.
> >
> > Umm...   What about .Linvalid_mask: in arch/xtensa/kernel/entry.S?
> > That's an obvious case for your make_task_dead().
> 
> Good catch.
> 
> Being in assembly it did not have anything after the name do_exit so it
> hid from my regex "[^A-Za-z0-9_]do_exit[^A-Za-z0-9]".  Thank you for
> finding that.

Umm...  What's wrong with '\<do_exit\>'?  Difference in catch:

missed 6
Documentation/trace/kprobes.rst:596:do_exit() case covered. do_execve() and do_fork() are not an issue.
arch/x86/entry/entry_32.S:1258: call    do_exit
arch/x86/entry/entry_64.S:1440: call    do_exit
arch/xtensa/kernel/entry.S:1436:        abi_call        do_exit
samples/bpf/test_cgrp2_tc.sh:114:do_exit() {
tools/testing/selftests/ftrace/test.d/kprobe/kprobe_multiprobe.tc:8:SYM2=do_exit

extra 3
arch/powerpc/mm/book3s64/radix_tlb.c:815:static void do_exit_flush_lazy_tlb(void *arg)
arch/powerpc/mm/book3s64/radix_tlb.c:830:       smp_call_function_many(mm_cpumask(mm), do_exit_flush_lazy_tlb,
tools/perf/ui/browsers/hists.c:2847:    act->fn = do_exit_browser;

Extra catch clearly contains nothing of interest (assuming it's not a result of a typo
in your regex in the first place - you seem to have omitted _ from the second set, and if
you add that back, these 3 hits go away).  And missed 6...  3 are outside of the kernel
source proper, and the rest are all genuine.  You've caught x86 ones (inside the
rewind_stack_do_exit variants) and missed the xtensa one...

\< and \> are GNUisms, but both git grep and grep (both on Linux and FreeBSD, at least)
handle them...  Or use \bdo_exit\b, for that matter (Perlism instead of GNUism, matching
both the beginnings and ends of words)...

  reply	other threads:[~2022-01-05 21:53 UTC|newest]

Thread overview: 137+ 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 [this message]
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  0:15     ` [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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