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Message-ID: <20240410165552.572304080@linutronix.de>
Date: Thu, 11 Apr 2024 00:46:57 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Anna-Maria Behnsen <anna-maria@...utronix.de>,
Frederic Weisbecker <frederic@...nel.org>,
John Stultz <jstultz@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
Stephen Boyd <sboyd@...nel.org>,
Eric Biederman <ebiederm@...ssion.com>,
Oleg Nesterov <oleg@...hat.com>
Subject: [patch V2 26/50] signal: Get rid of resched_timer logic
There is no reason for handing the *resched pointer argument through
several functions just to check whether the signal is related to a self
rearming posix timer.
SI_TIMER is only used by the posix timer code and cannot be queued from
user space. The only extra check in collect_signal() to verify whether the
queued signal is preallocated is not really useful. Some other places
already check purely the SI_TIMER type.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
kernel/signal.c | 25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -526,8 +526,7 @@ bool unhandled_signal(struct task_struct
return !tsk->ptrace;
}
-static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
- bool *resched_timer)
+static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info)
{
struct sigqueue *q, *first = NULL;
@@ -549,12 +548,6 @@ static void collect_signal(int sig, stru
still_pending:
list_del_init(&first->list);
copy_siginfo(info, &first->info);
-
- *resched_timer =
- (first->flags & SIGQUEUE_PREALLOC) &&
- (info->si_code == SI_TIMER) &&
- (info->si_sys_private);
-
__sigqueue_free(first);
} else {
/*
@@ -571,13 +564,12 @@ static void collect_signal(int sig, stru
}
}
-static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
- kernel_siginfo_t *info, bool *resched_timer)
+static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, kernel_siginfo_t *info)
{
int sig = next_signal(pending, mask);
if (sig)
- collect_signal(sig, pending, info, resched_timer);
+ collect_signal(sig, pending, info);
return sig;
}
@@ -589,17 +581,15 @@ static int __dequeue_signal(struct sigpe
int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type)
{
struct task_struct *tsk = current;
- bool resched_timer = false;
int signr;
lockdep_assert_held(&tsk->sighand->siglock);
*type = PIDTYPE_PID;
- signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
+ signr = __dequeue_signal(&tsk->pending, mask, info);
if (!signr) {
*type = PIDTYPE_TGID;
- signr = __dequeue_signal(&tsk->signal->shared_pending,
- mask, info, &resched_timer);
+ signr = __dequeue_signal(&tsk->signal->shared_pending, mask, info);
if (unlikely(signr == SIGALRM))
posixtimer_rearm_itimer(tsk);
@@ -626,7 +616,7 @@ int dequeue_signal(sigset_t *mask, kerne
}
if (IS_ENABLED(CONFIG_POSIX_TIMERS)) {
- if (unlikely(resched_timer))
+ if (unlikely(info->si_code == SI_TIMER && info->si_sys_private))
posixtimer_rearm(info);
}
@@ -1011,6 +1001,9 @@ static int __send_signal_locked(int sig,
lockdep_assert_held(&t->sighand->siglock);
+ if (WARN_ON_ONCE(!is_si_special(info) && info->si_code == SI_TIMER))
+ return 0;
+
result = TRACE_SIGNAL_IGNORED;
if (!prepare_signal(sig, t, force))
goto ret;
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