From: "Eric W. Biederman" <ebiederm@xmission.com>
To: linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, linux-api@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>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [PATCH 8/8] signal: Remove the helper signal_group_exit
Date: Mon, 13 Dec 2021 16:53:50 -0600 [thread overview]
Message-ID: <20211213225350.27481-8-ebiederm@xmission.com> (raw)
In-Reply-To: <87a6ha4zsd.fsf@email.froward.int.ebiederm.org>
This helper is misleading. It tests for an ongoing exec as well as
the process having received a fatal signal.
Sometimes it is appropriate to treat an on-going exec differently than
a process that is shutting down due to a fatal signal. In particular
taking the fast path out of exit_signals instead of retargeting
signals is not appropriate during exec, and not changing the the exit
code in do_group_exit during exec.
Removing the helper so that both cases must be coded for explicitly
makes it more obvious what is going on as both cases must be coded for
explicitly.
While removing the helper fix the two cases where I have observed
using signal_group_helper resulted in the wrong result.
For the unset exit_code in do_group_exit during an exec I use 0 as I
think that is what group_exit_code has been set to most of the time.
During a thread group stop group_exit_code is set to the stop signal
and when the thread group receives SIGCONT group_exit_code is reset to
0.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
fs/coredump.c | 5 +++--
fs/exec.c | 2 +-
include/linux/sched/signal.h | 7 -------
kernel/exit.c | 8 ++++++--
kernel/signal.c | 8 +++++---
5 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/fs/coredump.c b/fs/coredump.c
index ef56595a0d87..09302a6a0d80 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -372,11 +372,12 @@ static int zap_process(struct task_struct *start, int exit_code)
static int zap_threads(struct task_struct *tsk,
struct core_state *core_state, int exit_code)
{
+ struct signal_struct *signal = tsk->signal;
int nr = -EAGAIN;
spin_lock_irq(&tsk->sighand->siglock);
- if (!signal_group_exit(tsk->signal)) {
- tsk->signal->core_state = core_state;
+ if (!(signal->flags & SIGNAL_GROUP_EXIT) && !signal->group_exec_task) {
+ signal->core_state = core_state;
nr = zap_process(tsk, exit_code);
clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
tsk->flags |= PF_DUMPCORE;
diff --git a/fs/exec.c b/fs/exec.c
index 9d2925811011..82db656ca709 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1045,7 +1045,7 @@ static int de_thread(struct task_struct *tsk)
* Kill all other threads in the thread group.
*/
spin_lock_irq(lock);
- if (signal_group_exit(sig)) {
+ if ((sig->flags & SIGNAL_GROUP_EXIT) || sig->group_exec_task) {
/*
* Another group action in progress, just
* return so that the signal is processed.
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index d3248aba5183..b6ecb9fc4cd2 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -271,13 +271,6 @@ static inline void signal_set_stop_flags(struct signal_struct *sig,
sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
}
-/* If true, all threads except ->group_exec_task have pending SIGKILL */
-static inline int signal_group_exit(const struct signal_struct *sig)
-{
- return (sig->flags & SIGNAL_GROUP_EXIT) ||
- (sig->group_exec_task != NULL);
-}
-
extern void flush_signals(struct task_struct *);
extern void ignore_signals(struct task_struct *);
extern void flush_signal_handlers(struct task_struct *, int force_default);
diff --git a/kernel/exit.c b/kernel/exit.c
index 527c5e4430ae..e7104f803be0 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -907,15 +907,19 @@ do_group_exit(int exit_code)
BUG_ON(exit_code & 0x80); /* core dumps don't get here */
- if (signal_group_exit(sig))
+ if (sig->flags & SIGNAL_GROUP_EXIT)
exit_code = sig->group_exit_code;
+ else if (sig->group_exec_task)
+ exit_code = 0;
else if (!thread_group_empty(current)) {
struct sighand_struct *const sighand = current->sighand;
spin_lock_irq(&sighand->siglock);
- if (signal_group_exit(sig))
+ if (sig->flags & SIGNAL_GROUP_EXIT)
/* Another thread got here before we took the lock. */
exit_code = sig->group_exit_code;
+ else if (sig->group_exec_task)
+ exit_code = 0;
else {
sig->group_exit_code = exit_code;
sig->flags = SIGNAL_GROUP_EXIT;
diff --git a/kernel/signal.c b/kernel/signal.c
index 9eb3e2c1f9f7..860d844542b2 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2392,7 +2392,8 @@ static bool do_signal_stop(int signr)
WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
- unlikely(signal_group_exit(sig)))
+ unlikely(sig->flags & SIGNAL_GROUP_EXIT) ||
+ unlikely(sig->group_exec_task))
return false;
/*
* There is no group stop already in progress. We must
@@ -2699,7 +2700,8 @@ bool get_signal(struct ksignal *ksig)
enum pid_type type;
/* Has this task already been marked for death? */
- if (signal_group_exit(signal)) {
+ if ((signal->flags & SIGNAL_GROUP_EXIT) ||
+ signal->group_exec_task) {
ksig->info.si_signo = signr = SIGKILL;
sigdelset(¤t->pending.signal, SIGKILL);
trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
@@ -2955,7 +2957,7 @@ void exit_signals(struct task_struct *tsk)
*/
cgroup_threadgroup_change_begin(tsk);
- if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
+ if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
tsk->flags |= PF_EXITING;
cgroup_threadgroup_change_end(tsk);
return;
--
2.29.2
prev parent reply other threads:[~2021-12-13 22:55 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
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 ` Eric W. Biederman [this message]
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