From: ebiederm@xmission.com (Eric W. Biederman)
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Michael Schmitz <schmitzmic@gmail.com>,
linux-arch <linux-arch@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>, Oleg Nesterov <oleg@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Richard Henderson <rth@twiddle.net>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
alpha <linux-alpha@vger.kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
linux-m68k <linux-m68k@lists.linux-m68k.org>,
Arnd Bergmann <arnd@kernel.org>,
Ley Foon Tan <ley.foon.tan@intel.com>, Tejun Heo <tj@kernel.org>,
Kees Cook <keescook@chromium.org>
Subject: [PATCH 7/9] signal: Make individual tasks exiting a first class concept.
Date: Thu, 24 Jun 2021 14:02:50 -0500 [thread overview]
Message-ID: <87y2az5bmt.fsf_-_@disp2133> (raw)
In-Reply-To: <875yy3850g.fsf_-_@disp2133> (Eric W. Biederman's message of "Thu, 24 Jun 2021 13:57:35 -0500")
Implement start_task_exit_locked and rewrite the de_thread logic
in exec using it.
Calling start_task_exit_locked is equivalent to asyncrhonously
calling exit(2) aka pthread_exit on a task.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
fs/exec.c | 10 +++++++++-
include/linux/sched/jobctl.h | 2 ++
include/linux/sched/signal.h | 1 +
kernel/signal.c | 37 ++++++++++++++++--------------------
4 files changed, 28 insertions(+), 22 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 18594f11c31f..b6f50213f0a0 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1040,6 +1040,7 @@ static int de_thread(struct task_struct *tsk)
struct signal_struct *sig = tsk->signal;
struct sighand_struct *oldsighand = tsk->sighand;
spinlock_t *lock = &oldsighand->siglock;
+ struct task_struct *t;
if (thread_group_empty(tsk))
goto no_thread_group;
@@ -1058,7 +1059,14 @@ static int de_thread(struct task_struct *tsk)
}
sig->group_exit_task = tsk;
- sig->notify_count = zap_other_threads(tsk);
+ sig->group_stop_count = 0;
+ sig->notify_count = 0;
+ __for_each_thread(sig, t) {
+ if (t == tsk)
+ continue;
+ sig->notify_count++;
+ start_task_exit_locked(t, SIGKILL);
+ }
if (!thread_group_leader(tsk))
sig->notify_count--;
diff --git a/include/linux/sched/jobctl.h b/include/linux/sched/jobctl.h
index fa067de9f1a9..e94833b0c819 100644
--- a/include/linux/sched/jobctl.h
+++ b/include/linux/sched/jobctl.h
@@ -19,6 +19,7 @@ struct task_struct;
#define JOBCTL_TRAPPING_BIT 21 /* switching to TRACED */
#define JOBCTL_LISTENING_BIT 22 /* ptracer is listening for events */
#define JOBCTL_TRAP_FREEZE_BIT 23 /* trap for cgroup freezer */
+#define JOBCTL_TASK_EXITING_BIT 31 /* the task is exiting */
#define JOBCTL_STOP_DEQUEUED (1UL << JOBCTL_STOP_DEQUEUED_BIT)
#define JOBCTL_STOP_PENDING (1UL << JOBCTL_STOP_PENDING_BIT)
@@ -28,6 +29,7 @@ struct task_struct;
#define JOBCTL_TRAPPING (1UL << JOBCTL_TRAPPING_BIT)
#define JOBCTL_LISTENING (1UL << JOBCTL_LISTENING_BIT)
#define JOBCTL_TRAP_FREEZE (1UL << JOBCTL_TRAP_FREEZE_BIT)
+#define JOBCTL_TASK_EXITING (1UL << JOBCTL_TASK_EXITING_BIT)
#define JOBCTL_TRAP_MASK (JOBCTL_TRAP_STOP | JOBCTL_TRAP_NOTIFY)
#define JOBCTL_PENDING_MASK (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK)
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index c007e55cb119..a958381ba4a9 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -429,6 +429,7 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
}
void start_group_exit(int exit_code);
+void start_task_exit_locked(struct task_struct *task, int exit_code);
void task_join_group_stop(struct task_struct *task);
diff --git a/kernel/signal.c b/kernel/signal.c
index 95a076af600a..afbc001220dd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -264,6 +264,12 @@ static inline void print_dropped_signal(int sig)
current->comm, current->pid, sig);
}
+static void task_set_jobctl_exiting(struct task_struct *task, int exit_code)
+{
+ WARN_ON_ONCE(task->jobctl & ~JOBCTL_STOP_SIGMASK);
+ task->jobctl = JOBCTL_TASK_EXITING | (exit_code & JOBCTL_STOP_SIGMASK);
+}
+
/**
* task_set_jobctl_pending - set jobctl pending bits
* @task: target task
@@ -1407,28 +1413,15 @@ int force_sig_info(struct kernel_siginfo *info)
return force_sig_info_to_task(info, current, false);
}
-/*
- * Nuke all other threads in the group.
- */
-int zap_other_threads(struct task_struct *p)
+void start_task_exit_locked(struct task_struct *task, int exit_code)
{
- struct task_struct *t = p;
- int count = 0;
-
- p->signal->group_stop_count = 0;
-
- while_each_thread(p, t) {
- task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
- count++;
-
- /* Don't bother with already dead threads */
- if (t->exit_state)
- continue;
- sigaddset(&t->pending.signal, SIGKILL);
- signal_wake_up(t, 1);
+ task_clear_jobctl_pending(task, JOBCTL_PENDING_MASK);
+ /* Only bother with threads that might be alive */
+ if (!task->exit_state) {
+ task_set_jobctl_exiting(task, exit_code);
+ sigaddset(&task->pending.signal, SIGKILL);
+ signal_wake_up(task, 1);
}
-
- return count;
}
struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
@@ -2714,7 +2707,7 @@ bool get_signal(struct ksignal *ksig)
}
/* Has this task already been marked for death? */
- if (signal_group_exit(signal)) {
+ if (signal_group_exit(signal) || (current->jobctl & JOBCTL_TASK_EXITING)) {
ksig->info.si_signo = signr = SIGKILL;
sigdelset(¤t->pending.signal, SIGKILL);
trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
@@ -2874,6 +2867,8 @@ bool get_signal(struct ksignal *ksig)
if (signal_group_exit(signal)) {
/* Another thread got here before we took the lock. */
exit_code = signal->group_exit_code;
+ } else if (current->jobctl & JOBCTL_TASK_EXITING) {
+ exit_code = current->jobctl & JOBCTL_STOP_SIGMASK;
} else {
start_group_exit_locked(signal, exit_code);
}
--
2.20.1
next prev parent reply other threads:[~2021-06-24 19:03 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 20:57 Kernel stack read with PTRACE_EVENT_EXIT and io_uring threads Eric W. Biederman
2021-06-10 22:04 ` Linus Torvalds
2021-06-11 21:39 ` Eric W. Biederman
2021-06-11 23:26 ` Linus Torvalds
2021-06-13 21:54 ` Eric W. Biederman
2021-06-13 22:18 ` Linus Torvalds
2021-06-14 2:05 ` Michael Schmitz
2021-06-14 5:03 ` Michael Schmitz
2021-06-14 16:26 ` Eric W. Biederman
2021-06-14 22:26 ` Michael Schmitz
2021-06-15 19:30 ` Eric W. Biederman
2021-06-15 19:36 ` [PATCH] alpha: Add extra switch_stack frames in exit, exec, and kernel threads Eric W. Biederman
2021-06-15 22:02 ` Linus Torvalds
2021-06-16 16:32 ` Eric W. Biederman
2021-06-16 18:29 ` [PATCH 0/2] alpha/ptrace: Improved switch_stack handling Eric W. Biederman
2021-06-16 18:31 ` [PATCH 1/2] alpha/ptrace: Record and handle the absence of switch_stack Eric W. Biederman
2021-06-16 20:00 ` Linus Torvalds
2021-06-16 20:37 ` Linus Torvalds
2021-06-16 20:57 ` Eric W. Biederman
2021-06-16 21:02 ` Al Viro
2021-06-16 21:08 ` Linus Torvalds
2021-06-16 20:42 ` Eric W. Biederman
2021-06-16 20:17 ` Al Viro
2021-06-21 2:01 ` Michael Schmitz
2021-06-21 2:17 ` Linus Torvalds
2021-06-21 3:18 ` Michael Schmitz
2021-06-21 3:37 ` Linus Torvalds
2021-06-21 4:08 ` Michael Schmitz
2021-06-21 3:44 ` Al Viro
2021-06-21 5:31 ` Michael Schmitz
2021-06-21 2:27 ` Al Viro
2021-06-21 3:36 ` Michael Schmitz
2021-06-16 18:32 ` [PATCH 2/2] alpha/ptrace: Add missing switch_stack frames Eric W. Biederman
2021-06-16 20:25 ` Al Viro
2021-06-16 20:28 ` Al Viro
2021-06-16 20:49 ` Eric W. Biederman
2021-06-16 20:54 ` Al Viro
2021-06-16 20:47 ` Eric W. Biederman
2021-06-16 20:55 ` Al Viro
2021-06-16 20:50 ` [PATCH] alpha: Add extra switch_stack frames in exit, exec, and kernel threads Al Viro
2021-06-15 20:56 ` Kernel stack read with PTRACE_EVENT_EXIT and io_uring threads Michael Schmitz
2021-06-16 0:23 ` Finn Thain
2021-06-15 21:58 ` Linus Torvalds
2021-06-16 15:06 ` Eric W. Biederman
2021-06-21 13:54 ` Al Viro
2021-06-21 14:16 ` Al Viro
2021-06-21 16:50 ` Eric W. Biederman
2021-06-21 23:05 ` Al Viro
2021-06-22 16:39 ` Eric W. Biederman
2021-06-21 15:38 ` Linus Torvalds
2021-06-21 18:59 ` Al Viro
2021-06-21 19:22 ` Linus Torvalds
2021-06-21 19:45 ` Al Viro
2021-06-21 23:14 ` Linus Torvalds
2021-06-21 23:23 ` Al Viro
2021-06-21 23:36 ` Linus Torvalds
2021-06-22 21:02 ` Eric W. Biederman
2021-06-22 21:48 ` Michael Schmitz
2021-06-23 5:26 ` Michael Schmitz
2021-06-23 14:36 ` Eric W. Biederman
2021-06-22 0:01 ` Michael Schmitz
2021-06-22 20:04 ` Michael Schmitz
2021-06-22 20:18 ` Al Viro
2021-06-22 21:57 ` Michael Schmitz
2021-06-21 20:03 ` Eric W. Biederman
2021-06-21 23:15 ` Linus Torvalds
2021-06-22 20:52 ` Eric W. Biederman
2021-06-23 0:41 ` Linus Torvalds
2021-06-23 14:33 ` Eric W. Biederman
2021-06-24 18:57 ` [PATCH 0/9] Refactoring exit Eric W. Biederman
2021-06-24 18:59 ` [PATCH 1/9] signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL) Eric W. Biederman
2021-06-24 18:59 ` [PATCH 2/9] signal/seccomp: Refactor seccomp signal and coredump generation Eric W. Biederman
2021-06-26 3:17 ` Kees Cook
2021-06-28 19:21 ` Eric W. Biederman
2021-06-24 19:00 ` [PATCH 3/9] signal/seccomp: Dump core when there is only one live thread Eric W. Biederman
2021-06-26 3:20 ` Kees Cook
2021-06-24 19:01 ` [PATCH 4/9] signal: Factor start_group_exit out of complete_signal Eric W. Biederman
2021-06-24 20:04 ` Linus Torvalds
2021-06-26 3:24 ` Kees Cook
2021-06-24 19:01 ` [PATCH 5/9] signal/group_exit: Use start_group_exit in place of do_group_exit Eric W. Biederman
2021-06-26 3:35 ` Kees Cook
2021-06-24 19:02 ` [PATCH 6/9] signal: Fold do_group_exit into get_signal fixing io_uring threads Eric W. Biederman
2021-06-26 3:42 ` Kees Cook
2021-06-28 19:25 ` Eric W. Biederman
2021-06-24 19:02 ` Eric W. Biederman [this message]
2021-06-24 20:11 ` [PATCH 7/9] signal: Make individual tasks exiting a first class concept Linus Torvalds
2021-06-24 21:37 ` Eric W. Biederman
2021-06-24 19:03 ` [PATCH 8/9] signal/task_exit: Use start_task_exit in place of do_exit Eric W. Biederman
2021-06-26 5:56 ` Kees Cook
2021-06-24 19:03 ` [PATCH 9/9] signal: Move PTRACE_EVENT_EXIT into get_signal Eric W. Biederman
2021-06-24 22:45 ` [PATCH 0/9] Refactoring exit Al Viro
2021-06-27 22:13 ` Al Viro
2021-06-27 22:59 ` Michael Schmitz
2021-06-28 7:31 ` Geert Uytterhoeven
2021-06-28 16:20 ` Eric W. Biederman
2021-06-28 17:14 ` Michael Schmitz
2021-06-28 19:17 ` Geert Uytterhoeven
2021-06-28 20:13 ` Michael Schmitz
2021-06-28 21:18 ` Geert Uytterhoeven
2021-06-28 23:42 ` Michael Schmitz
2021-06-29 20:28 ` [CFT][PATCH] exit/bdflush: Remove the deprecated bdflush system call Eric W. Biederman
2021-06-29 21:45 ` Michael Schmitz
2021-06-30 8:24 ` Geert Uytterhoeven
2021-06-30 8:37 ` Arnd Bergmann
2021-06-30 12:30 ` Cyril Hrubis
2021-06-28 19:02 ` [PATCH 0/9] Refactoring exit Eric W. Biederman
2021-06-21 19:24 ` Kernel stack read with PTRACE_EVENT_EXIT and io_uring threads Al Viro
2021-06-21 23:24 ` Michael Schmitz
2021-06-16 7:38 ` Geert Uytterhoeven
2021-06-16 19:40 ` Michael Schmitz
2021-06-12 23:38 ` [PATCH v1] m68k: save extra registers on sys_exit and sys_exit_group syscall entry Michael Schmitz
2021-06-13 19:59 ` Linus Torvalds
2021-06-13 20:07 ` Michael Schmitz
2021-06-13 20:26 ` Linus Torvalds
2021-06-13 20:33 ` Linus Torvalds
2021-06-13 20:47 ` Linus Torvalds
2021-06-14 7:13 ` Michael Schmitz
2021-06-14 7:40 ` Andreas Schwab
2021-06-14 8:19 ` Michael Schmitz
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