From: "Eric W. Biederman" <ebiederm@xmission.com>
To: linux-kernel@vger.kernel.org
Cc: 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>,
Al Viro <viro@ZenIV.linux.org.uk>,
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>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH 01/10] exit/s390: Remove dead reference to do_exit from copy_thread
Date: Wed, 8 Dec 2021 14:25:23 -0600 [thread overview]
Message-ID: <20211208202532.16409-1-ebiederm@xmission.com> (raw)
In-Reply-To: <87a6ha4zsd.fsf@email.froward.int.ebiederm.org>
My s390 assembly is not particularly good so I have read the history
of the reference to do_exit copy_thread and have been able to
verify that do_exit is not used.
The general argument is that s390 has been changed to use the generic
kernel_thread and kernel_execve and the generic versions do not call
do_exit. So it is strange to see a do_exit reference sitting there.
The history of the do_exit reference in s390's version of copy_thread
seems conclusive that the do_exit reference is something that lingers
and should have been removed several years ago.
Up through 8d19f15a60be ("[PATCH] s390 update (1/27): arch.") the
s390 code made a call to the exit(2) system call when a kernel thread
finished. Then kernel_thread_starter was added which branched
directly to the value in register 11 when the kernel thread finshed.
The value in register 11 was set in kernel_thread to
"regs.gprs[11] = (unsigned long) do_exit"
In commit 37fe5d41f640 ("s390: fold kernel_thread_helper() into
ret_from_fork()") kernel_thread_starter was moved into entry.S and
entry64.S unchanged (except for the syntax differences between inline
assemly and in the assembly file).
In commit f9a7e025dfc2 ("s390: switch to generic kernel_thread()") the
assignment to "gprs[11]" was moved into copy_thread from the old
kernel_thread. The helper kernel_thread_starter was still being used
and was still branching to "%r11" at the end.
In commit 30dcb0996e40 ("s390: switch to saner kernel_execve()
semantics") kernel_thread_starter was changed to unconditionally
branch to sysc_tracenogo instead to %r11 which held the value of
do_exit. Unfortunately copy_thread was not updated to stop passing
do_exit in "gprs[11]".
In commit 56e62a737028 ("s390: convert to generic entry")
kernel_thread_starter was replaced by __ret_from_fork. And the code
still continued to pass do_exit in "gprs[11]" despite __ret_from_fork
not caring in the slightest.
Remove this dead reference to do_exit to make it clear that s390 is
not doing anything with do_exit in copy_thread.
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 30dcb0996e40 ("s390: switch to saner kernel_execve() semantics")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
arch/s390/kernel/process.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index e8858b2de24b..71d86f73b02c 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -139,7 +139,6 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
(unsigned long)__ret_from_fork;
frame->childregs.gprs[9] = new_stackp; /* function */
frame->childregs.gprs[10] = arg;
- frame->childregs.gprs[11] = (unsigned long)do_exit;
frame->childregs.orig_gpr2 = -1;
frame->childregs.last_break = 1;
return 0;
--
2.29.2
next prev parent reply other threads:[~2021-12-08 20:26 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 ` Eric W. Biederman [this message]
2021-12-12 17:48 ` [PATCH 01/10] exit/s390: Remove dead reference to do_exit from copy_thread 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 0:15 ` [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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