From nobody Mon Nov 25 02:42:08 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 0BA5F1C7B62 for ; Thu, 31 Oct 2024 15:46:43 +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=1730389605; cv=none; b=RcyCt0AqCELCx1UmP+K7b1RqI+a77LNFRyoWHZhtuxnYLbALshih3xfCl/zuLbGx3mHJgFvw+iLIZlFRhJRb7TN3+Nowme9dQTCfOLcPgmlxMTuyjIXR2mO673RdH1R05Xis4NGLIEkXqz0L36ETCG9PrBoLQoHLATgSCcH8s3M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730389605; c=relaxed/simple; bh=a7KcfJ0H5yG9o+hAQ68pX3T59R0HehkYopkBoSQyZYE=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=BNLDjTVVTYuSNgvqgKjW63JDaiYsWe+V0qFmJJyIqqr/tp6BWac+T+bBVmFk3giAIc4Hjl8xaBvfkVMD9Dv4wJB+7VRK1jOLns2qnhpy9/Akv6Owai7lOukTZGlQCJ+oHUE8WJN+dCzS3+nFiYFYYJrF+T7hRmurNVroBNCNxs8= 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=kvjsj344; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=oZRZznzC; 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="kvjsj344"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="oZRZznzC" Message-ID: <20241031154425.498474639@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1730389601; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=RrNJyRQje7EybxKIECKyVfE3lGKZ40kOBzWpZXbTjgk=; b=kvjsj344D0SMtaztvIFUP9tSaiq2UKdQobo6n9JWHKIeVi+fR/F9iHeCF4DgZXPG4c/LKP lrV4KWafXAiRWllX1btSbCBxXc2Whzb8aP1rI4uKb2smBRU33xNihFMhnOBQ21Gz4/9cOQ 2GVX4j1gKEpXcizqZXCjscdHbwWqE6lyITM9iDGqAkpMD2pLMosy6k/Sb6gxu+zzAJDcUn Z+rSfwVE81IRfrizgdd8mCz03rns2RJ5ygZDkQNDwxFNxrE9AZxV6Vr8/QKmV7kXXCh99a oTLpxAo2lzJZcyKESAmPxR8pRmNS0lnuhwO+cK0FQyMKH/raDvC3iKHqY5C+Aw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1730389601; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=RrNJyRQje7EybxKIECKyVfE3lGKZ40kOBzWpZXbTjgk=; b=oZRZznzCLA38TqeNegvLYHRYeMDO552GTQFKUokJhhuMHNLt6NG3yJDSANRvn/ytHyUDDM wEVSB+OpZuHcPuBw== From: Thomas Gleixner To: LKML Cc: Anna-Maria Behnsen , Frederic Weisbecker , John Stultz , Peter Zijlstra , Ingo Molnar , Stephen Boyd , Eric Biederman , Oleg Nesterov Subject: [patch v6 15/20] posix-timers: Handle ignored list on delete and exit References: <20241031151625.361697424@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Thu, 31 Oct 2024 16:46:41 +0100 (CET) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Thomas Gleixner To handle posix timer signals on sigaction(SIG_IGN) properly, the timers will be queued on a separate ignored list. Add the necessary cleanup code for timer_delete() and exit_itimers(). Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Reviewed-by: Frederic Weisbecker --- V6: Warn when the ignored list is not empty after deleting all timers in exit_itimers() --- include/linux/posix-timers.h | 4 +++- kernel/time/posix-timers.c | 26 ++++++++++++++++++++++++++ 2 files changed, 29 insertions(+), 1 deletion(-) --- --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -152,7 +152,8 @@ static inline void posix_cputimers_init_ =20 /** * struct k_itimer - POSIX.1b interval timer structure. - * @list: List head for binding the timer to signals->posix_timers + * @list: List node for binding the timer to tsk::signal::posix_timers + * @ignored_list: List node for tracking ignored timers in tsk::signal::ig= nored_posix_timers * @t_hash: Entry in the posix timer hash table * @it_lock: Lock protecting the timer * @kclock: Pointer to the k_clock struct handling this timer @@ -176,6 +177,7 @@ static inline void posix_cputimers_init_ */ struct k_itimer { struct hlist_node list; + struct hlist_node ignored_list; struct hlist_node t_hash; spinlock_t it_lock; const struct k_clock *kclock; --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -1027,6 +1027,18 @@ int common_timer_del(struct k_itimer *ti return 0; } =20 +/* + * If the deleted timer is on the ignored list, remove it and + * drop the associated reference. + */ +static inline void posix_timer_cleanup_ignored(struct k_itimer *tmr) +{ + if (!hlist_unhashed(&tmr->ignored_list)) { + hlist_del_init(&tmr->ignored_list); + posixtimer_putref(tmr); + } +} + static inline int timer_delete_hook(struct k_itimer *timer) { const struct k_clock *kc =3D timer->kclock; @@ -1059,6 +1071,7 @@ SYSCALL_DEFINE1(timer_delete, timer_t, t =20 spin_lock(¤t->sighand->siglock); hlist_del(&timer->list); + posix_timer_cleanup_ignored(timer); spin_unlock(¤t->sighand->siglock); /* * A concurrent lookup could check timer::it_signal lockless. It @@ -1110,6 +1123,8 @@ static void itimer_delete(struct k_itime } hlist_del(&timer->list); =20 + posix_timer_cleanup_ignored(timer); + /* * Setting timer::it_signal to NULL is technically not required * here as nothing can access the timer anymore legitimately via @@ -1142,6 +1157,17 @@ void exit_itimers(struct task_struct *ts /* The timers are not longer accessible via tsk::signal */ while (!hlist_empty(&timers)) itimer_delete(hlist_entry(timers.first, struct k_itimer, list)); + + /* + * There should be no timers on the ignored list. itimer_delete() has + * mopped them up. + */ + if (!WARN_ON_ONCE(!hlist_empty(&tsk->signal->ignored_posix_timers))) + return; + + hlist_move_list(&tsk->signal->ignored_posix_timers, &timers); + while (!hlist_empty(&timers)) + posix_timer_cleanup_ignored(hlist_entry(timers.first, struct k_itimer, l= ist)); } =20 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,