From nobody Sun Nov 24 05:56:09 2024 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF07A156C6A; Thu, 7 Nov 2024 01:31:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730943101; cv=none; b=hKUxEf2xMMyDdR4XRtPpe3JOpyFqwVuSEFBtZHGhM1pQhha7hebneuxdHtyBsIqPseRGO+9KB6cUL7HAnHnb6e0b1B07qc0qukFfNE6yFQ+Fh9aO7XXyqbWBQL26IuYx8kZ6BykYEmjQlUN2YSeAt59ufSSKHwobAdUGkuZTi5I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730943101; c=relaxed/simple; bh=yn2m0GCLAxRzjp1EPk7YK5XwqsNpmro94ow5AueSAvA=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=BfhtYob1iRk3S+neCCdibyITAKZQ4TpJrCe2N4sK4OcAkD9YqI3pCVIQmGQJ2sJvDkkzOWlFmUuLkuQKvsVb1Pw5PD/p1YhYNQKZbXfhuEY4CrIK7hU8bUyiUB5siWhEdhVr3iaclGX+mZvaJsZ+fFU5QP5BrxBjlXjHSIpsRCo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=VGdMZnFy; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Ibn3aglA; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="VGdMZnFy"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Ibn3aglA" Date: Thu, 07 Nov 2024 01:31:37 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1730943098; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z0KMnh3dnQOWm3YnWAHfX2WsM2j4FWoxEwK4SdlIO4Q=; b=VGdMZnFycIRFO/Hr+4Kw412VAt2QubWwVeUKqIvpjPGH+DmaOcv9bjON38XMIkJUvr7DWq AmrQ5WL0HilV7I02yK7BptkLWnHdc2JtZV/zqRnzw+r/ZjSQJlys7J9P/uS50F4zh/U2Cp Yju0qwul3h19qMNAuBhu7ABIYHwb7B9ed7QebgIezG62roY0crP0nVImeDYazhSVrp19Gz l3eH1nLaWFIohxRCItt4/7viYGLfIOwpeDipYy07nIMKhb79TKIZTkfBhHjP7WUXoq1vuD IaRAilDnwbEMpv+DX31YMH/kFp+dg+iSgfirdINX47DWvylOueo4gDFMtujbWQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1730943098; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z0KMnh3dnQOWm3YnWAHfX2WsM2j4FWoxEwK4SdlIO4Q=; b=Ibn3aglA7k7WRQmMO6O/Mim20MHeVmgAJZBtI2rkyQVlSZigAqHeceEJwjKdMwiJGgDgU9 GmKpN9NJemXAQXAg== From: "tip-bot2 for Thomas Gleixner" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: timers/core] signal: Refactor send_sigqueue() Cc: Thomas Gleixner , Frederic Weisbecker , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20241105064213.586453412@linutronix.de> References: <20241105064213.586453412@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <173094309732.32228.16579868833242464894.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the timers/core branch of tip: Commit-ID: 0360ed14d9826678a50fa2b873e522a24cd3c018 Gitweb: https://git.kernel.org/tip/0360ed14d9826678a50fa2b873e522a24= cd3c018 Author: Thomas Gleixner AuthorDate: Tue, 05 Nov 2024 09:14:42 +01:00 Committer: Thomas Gleixner CommitterDate: Thu, 07 Nov 2024 02:14:44 +01:00 signal: Refactor send_sigqueue() To handle posix timers which have their signal ignored via SIG_IGN properly it is required to requeue a ignored signal for delivery when SIG_IGN is lifted so the timer gets rearmed. Split the required code out of send_sigqueue() so it can be reused in context of sigaction(). While at it rename send_sigqueue() to posixtimer_send_sigqueue() so its clear what this is about. Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/20241105064213.586453412@linutronix.de --- include/linux/posix-timers.h | 1 +- include/linux/sched/signal.h | 1 +- kernel/signal.c | 82 +++++++++++++++++++---------------- kernel/time/posix-timers.c | 2 +- 4 files changed, 47 insertions(+), 39 deletions(-) diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 9471765..52611ea 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -109,6 +109,7 @@ static inline void posix_cputimers_rt_watchdog(struct p= osix_cputimers *pct, =20 void posixtimer_rearm_itimer(struct task_struct *p); bool posixtimer_init_sigqueue(struct sigqueue *q); +int posixtimer_send_sigqueue(struct k_itimer *tmr); bool posixtimer_deliver_signal(struct kernel_siginfo *info); void posixtimer_free_timer(struct k_itimer *timer); =20 diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index bd9f569..36283c1 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -340,7 +340,6 @@ extern int send_sig(int, struct task_struct *, int); extern int zap_other_threads(struct task_struct *p); extern struct sigqueue *sigqueue_alloc(void); extern void sigqueue_free(struct sigqueue *); -extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type, i= nt si_private); extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *); =20 static inline void clear_notify_signal(void) diff --git a/kernel/signal.c b/kernel/signal.c index 911ed3a..5b71e26 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1947,40 +1947,54 @@ void sigqueue_free(struct sigqueue *q) __sigqueue_free(q); } =20 -int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type,= int si_private) +static void posixtimer_queue_sigqueue(struct sigqueue *q, struct task_stru= ct *t, enum pid_type type) { - int sig =3D q->info.si_signo; struct sigpending *pending; + int sig =3D q->info.si_signo; + + signalfd_notify(t, sig); + pending =3D (type !=3D PIDTYPE_PID) ? &t->signal->shared_pending : &t->pe= nding; + list_add_tail(&q->list, &pending->list); + sigaddset(&pending->signal, sig); + complete_signal(sig, t, type); +} + +/* + * This function is used by POSIX timers to deliver a timer signal. + * Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID + * set), the signal must be delivered to the specific thread (queues + * into t->pending). + * + * Where type is not PIDTYPE_PID, signals must be delivered to the + * process. In this case, prefer to deliver to current if it is in + * the same thread group as the target process, which avoids + * unnecessarily waking up a potentially idle task. + */ +static inline struct task_struct *posixtimer_get_target(struct k_itimer *t= mr) +{ + struct task_struct *t =3D pid_task(tmr->it_pid, tmr->it_pid_type); + + if (t && tmr->it_pid_type !=3D PIDTYPE_PID && same_thread_group(t, curren= t)) + t =3D current; + return t; +} + +int posixtimer_send_sigqueue(struct k_itimer *tmr) +{ + struct sigqueue *q =3D tmr->sigq; + int sig =3D q->info.si_signo; struct task_struct *t; unsigned long flags; int ret, result; =20 - if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC))) - return 0; - if (WARN_ON_ONCE(q->info.si_code !=3D SI_TIMER)) - return 0; - - ret =3D -1; - rcu_read_lock(); + guard(rcu)(); =20 - /* - * This function is used by POSIX timers to deliver a timer signal. - * Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID - * set), the signal must be delivered to the specific thread (queues - * into t->pending). - * - * Where type is not PIDTYPE_PID, signals must be delivered to the - * process. In this case, prefer to deliver to current if it is in - * the same thread group as the target process, which avoids - * unnecessarily waking up a potentially idle task. - */ - t =3D pid_task(pid, type); + t =3D posixtimer_get_target(tmr); if (!t) - goto ret; - if (type !=3D PIDTYPE_PID && same_thread_group(t, current)) - t =3D current; + return -1; + if (!likely(lock_task_sighand(t, &flags))) - goto ret; + return -1; =20 /* * Update @q::info::si_sys_private for posix timer signals with @@ -1988,30 +2002,24 @@ int send_sigqueue(struct sigqueue *q, struct pid *p= id, enum pid_type type, int s * decides based on si_sys_private whether to invoke * posixtimer_rearm() or not. */ - q->info.si_sys_private =3D si_private; + q->info.si_sys_private =3D tmr->it_signal_seq; =20 ret =3D 1; /* the signal is ignored */ - result =3D TRACE_SIGNAL_IGNORED; - if (!prepare_signal(sig, t, false)) + if (!prepare_signal(sig, t, false)) { + result =3D TRACE_SIGNAL_IGNORED; goto out; + } =20 ret =3D 0; if (unlikely(!list_empty(&q->list))) { result =3D TRACE_SIGNAL_ALREADY_PENDING; goto out; } - - signalfd_notify(t, sig); - pending =3D (type !=3D PIDTYPE_PID) ? &t->signal->shared_pending : &t->pe= nding; - list_add_tail(&q->list, &pending->list); - sigaddset(&pending->signal, sig); - complete_signal(sig, t, type); + posixtimer_queue_sigqueue(q, t, tmr->it_pid_type); result =3D TRACE_SIGNAL_DELIVERED; out: - trace_signal_generate(sig, &q->info, t, type !=3D PIDTYPE_PID, result); + trace_signal_generate(sig, &q->info, t, tmr->it_pid_type !=3D PIDTYPE_PID= , result); unlock_task_sighand(t, &flags); -ret: - rcu_read_unlock(); return ret; } #endif /* CONFIG_POSIX_TIMERS */ diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index f18d64c..0901ed9 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -307,7 +307,7 @@ int posix_timer_queue_signal(struct k_itimer *timr) =20 timr->it_status =3D state; =20 - ret =3D send_sigqueue(timr->sigq, timr->it_pid, timr->it_pid_type, timr->= it_signal_seq); + ret =3D posixtimer_send_sigqueue(timr); /* If we failed to send the signal the timer stops. */ return ret > 0; }