From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794414530; b=hzJcGt8JHouwLv6jW3eHi9E4IabsRRqlOepGU3/Nm8mQYwURsmbsGSDzsw8NgqNYPZ+a dvjfzJrAdi5+gArmxyEx5zDOLv/NLyq8qB082fA2OhHrnkT80hCFuOQ9JHRS1VyKQlZYr GeNUgi/mBVOf4TjJCATyAKdaJ5b4f8+WrKDRWSY/wOfxX1KzWIfcQLgS2vLcpTFACrW9R QnGlnfttr+MEIhxV7zQlgwWkeVvKmlCa0Ckf7Arwr+7+FNIoK6E2F8mDPx8biFMOaahZM bo/G8CfL160sgomNIyl1ZeT/7ydSOfqyQATn580ND2jRdOsRE+RX0723Psx2k5Gfrow== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794414530; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=NdmV1kyGt5F5R+ciWfbYycq4p7UHIAsfEORxrUphXSQ=; b=THSUhycp7nhpXAOcmJqXotWAqXTyWzlybYTAtQwBTAYGaVqDuKorMpFVHgALG3NGMhh1 mh9DMJPT9IAVtccA4xgEHnGgu61JaL85cM33fJkSGf6uu+prfqLA77KjZSkXr0Ys4CI5Z aZCnLOvsMPrIvJIOTRqUlztPy1bI5ElCmVA3CU2JiuV+2maKc5vUK7TudGV2YGJ3m7fEX uZrTdn/AK01PMKT5d0Y0pH0h4o9mf1t9DYP6iUzAdQho+S/j1ReUZfUnDvAkNdRjJPou3 gyrvYhj1ir7m5SRus69wvTG2RObW40znWFDv3JBHZK5EVdaBmESih9QjpDl3a3Onclg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=aPTrSB5m; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 213E760A380E for ; Wed, 11 Nov 2026 16:28:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=aPTrSB5m Received: by smtp.kernel.org (Postfix) with ESMTPSA id 532731F00A08; Wed, 11 Nov 2026 16:28:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794414529; bh=NdmV1kyGt5F5R+ciWfbYycq4p7UHIAsfEORxrUphXSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=aPTrSB5mFDH7rqzTyawz9rPtLREaFAqnCpf+68o3Q/u/e3+np2D6qcqHR138uLC+Q 26Xgqbq/xNKbIdrSWrxxxqS+oEihieiyNFL+hTMZ0i3hA3ya8V2/oM/Sz+Jyom+6SZ Ye8PB7EFCUsnw846eq5nd0r16pgHe00WbBmajkPUd52F2ZCFLwvIbieY+Y+2F6CPEC uevg2vBafM+L45RtEbPtC6loVEG2uqEF24sLZzyQ7qefjgUki73BgMBAw6EkVjiE7B kaX93iBhDhf6/q77SwhAJxMFSoTkbMNRFrbtEWW70mO2vHI4N29ULFAyU5knRh7um3 TSZxBxqb5Pemg== From: Sasha Levin To: stable@vger.kernel.org Cc: Hung-Jui Lin , Thomas Gleixner , Sasha Levin Subject: [PATCH 6.6.y] posix-timers: Report zero remaining time for disarmed SIGEV_NONE timers Date: Wed, 11 Nov 2026 11:28:48 -0500 Message-ID: <20261111162829.3280831-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107053924-failed-6.6-141a27750ec3@kernel.org> References: <20261107053924-failed-6.6-141a27750ec3@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Hung-Jui Lin [ Upstream commit 141a27750ec3d91ad9d1ad1764ebb5e51b963478 ] SIGEV_NONE timers are never queued. common_timer_get() emulates their expiry by computing the remaining time from the stored expiry value. Because an armed SIGEV_NONE oneshot timer is not queued, its it_status stays POSIX_TIMER_DISARMED. So common_timer_get() cannot use it_status to skip a disarmed SIGEV_NONE timer and evaluates the stored expiry value for all SIGEV_NONE timers. Disarming a timer with timer_settime() and a zero it_value cancels the timer and sets it_status to POSIX_TIMER_DISARMED, but leaves the expiry value unchanged. As a consequence, timer_gettime() on a disarmed SIGEV_NONE timer reports the remaining time of the previous arming until that time has passed, instead of zero as POSIX requires for a disarmed timer. Example with a CLOCK_MONOTONIC timer armed with it_value = 10ms and it_interval = 100ms, then disarmed with an all-zero itimerspec: armed: it_value = 0.009999000 it_interval = 0.100000000 disarmed: it_value = 0.008700792 it_interval = 0.000000000 SIGEV_SIGNAL timers and SIGEV_NONE CPU timers report zero in the same situation. All clocks which use common_timer_get() are affected, including the alarm timer clocks. Mark SIGEV_NONE timers as POSIX_TIMER_ARMED when they are armed, so that common_timer_get() returns early for every disarmed timer. Forward SIGEV_NONE interval timers in common_timer_get() regardless of it_status, as they are never queued and therefore never forwarded by the expiry code. After the change the disarmed timer above reports zero. Armed SIGEV_NONE oneshot and interval timers on CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME and CLOCK_BOOTTIME_ALARM still report their remaining time, and the posix_timers selftest passes. Fixes: becf8b5d00f4 ("[PATCH] hrtimer: convert posix timers completely") Signed-off-by: Hung-Jui Lin Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261023151411.28685-1-alex.lin.programmer@gmail.com [ sashal: adapted timer state handling to use the it_active flag instead of it_status constants ] Signed-off-by: Sasha Levin --- kernel/time/posix-timers.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index 7534069f60333..ffaf5f6c8eb40 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -648,16 +648,8 @@ void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting) if (iv) { cur_setting->it_interval = ktime_to_timespec64(iv); } else if (!timr->it_active) { - /* - * SIGEV_NONE oneshot timers are never queued and therefore - * timr->it_active is always false. The check below - * vs. remaining time will handle this case. - * - * For all other timers there is nothing to update here, so - * return. - */ - if (!sig_none) - return; + /* Nothing to update for a disarmed timer */ + return; } now = kc->clock_get_ktime(timr->it_clock); @@ -894,7 +886,15 @@ int common_timer_set(struct k_itimer *timr, int flags, sigev_none = timr->it_sigev_notify == SIGEV_NONE; kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none); - timr->it_active = !sigev_none; + /* + * SIGEV_NONE timers are not queued, but mark them armed + * so that common_timer_get() can tell them apart from + * disarmed timers. An expired SIGEV_NONE timer stays + * armed, which is harmless: common_timer_get() reports + * zero remaining time for it and it never reaches the + * signal delivery code. + */ + timr->it_active = 1; return 0; } -- 2.53.0