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=1794049920; b=gXhV6SX5NWm2MJ6/bbXn6V0kMrtrRN8/VuGWPcs98yNFE2utbPhBJcnrj1I9ZjoNzaTt +KZontvqbaOzXizZSwWE9A1R78dfbgpDgSDNbtenNAbH+9RzmWoU9LjSdqcJU6VrDPkef kXe8kQxsT0O/ie+8cxjWglElyfuBsYDse8ee3WMdQc3leoJhku4ZgGwZZtSM64G28fS6U IAiDqqSXu1BIpn+a/1Zu+/poH2yEE3c4HN1oil7Ys+WHZacnstSJYPBYIS7yTU0hVau17 IdZ6AySL9W3n+FHGLKemKxgt4IuTYgP0Ey4ZSlXjP0Hv9JhxDPMwWVysIXNnmcC7HzA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794049920; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=F1JasCfj79KBXo9iphg32XJewx/2db7l0RNY/faGOSQ=; b=COd9WAnMK5PZb7XQIgDLazXxkX0duJGsydUjc0YL9W39oj22iX+J4mT+UnwbV6JBRtMF dU3xAzVojP+HrEt8dAaGuaHri1WnVqQAH04ELOM/CPNkLBc7UImXD1uFU66hvQ8AysTa0 8wX8Ol+9icql2pXyqQMqQ5riMfdqSHuq+UXlslKmHp11QGDmC3W/4FABrivJderxdi4FS PZGXQebXyKhpZGMal0TnE6Qesfl8omceac7ynmcXpRWypOCEJ+uo/hmuHHk5AE6ZIYNLe fxNvwerUIxsEE+a/mtE5vUtv2+86qjmFaeXlBKPyJGp3w+nNuvBXpIj+72uFxdhAE4g== 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=dt1G0BB0; 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 37414606A326 for ; Sat, 7 Nov 2026 11:12:00 +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=dt1G0BB0 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B5771F0089F; Sat, 7 Nov 2026 11:11:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794049920; bh=F1JasCfj79KBXo9iphg32XJewx/2db7l0RNY/faGOSQ=; h=From:To:Cc:Subject:Date; b=dt1G0BB0kQIyfR4YkwBqSPGqlS9prQdB/l8NRG3ocrWPJPae8YKsoX1C9EFreIWm+ VELF5z0BhzW3XhPSzcQNmSDXCG9yF+xiCaTDORBcUcTAgW1cH5VJ85t6ikjowJaogd +Os0mm30F8LREM+Sf8rkdbb7J14X12powmkPrXNQYa31/H70v5ZUPalqy02Fv/ZgAb OS70qY+g0uIDXQRbK+nz9dBXyhKR10bvRK/rvRDL0cc7PMAnaZNyTLbei9Qy3NVdtZ +MJwRI3kqSyysqUBElq6h2ygyGdPOenhC2u3hgbRTqASyxNT86tSDeXaG23VgPBxZD nOR9dmS/4FOng== From: Sasha Levin To: peng_wang@linux.alibaba.com, frederic@kernel.org, herongguang@linux.alibaba.com, tglx@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] tick/nohz: Reevaluate the tick for kicks flushed outside hardirq" failed to apply to 5.15-stable tree Date: Sat, 7 Nov 2026 06:11:58 -0500 Message-ID: <20261107061158-failed-5.15-e389ae428847@kernel.org> X-Mailer: git-send-email 2.53.0 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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x e389ae428847a2e6a3b698b5967df68ccf90361c # git commit -s git send-email --to '' --in-reply-to '20261107061158-failed-5.15-e389ae428847@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From e389ae428847a2e6a3b698b5967df68ccf90361c Mon Sep 17 00:00:00 2001 From: Peng Wang Date: Fri, 23 Oct 2026 22:51:00 +0800 Subject: [PATCH] tick/nohz: Reevaluate the tick for kicks flushed outside hardirq The nohz full kick relies on interrupt exit to reevaluate the tick. However, a remote kick can also be flushed from task context without an interrupt exit guaranteed to follow. If a tick dependency is set or an earlier timer is queued after the idle-exit reevaluation, the required tick update can be delayed until another interrupt. Reevaluate the tick directly from the callback outside hardirq context. Keep the existing interrupt exit handling for hardirq callbacks. The offline flush remains harmless because tick_sched_timer_dying() has already cleared TS_FLAG_NOHZ. Fixes: 4b44a21dd640 ("irq_work, smp: Allow irq_work on call_single_queue") Fixes: a5183862e76f ("tick/nohz: Conditionally restart tick on idle exit") Suggested-by: Frederic Weisbecker Co-developed-by: He Rongguang Signed-off-by: He Rongguang Signed-off-by: Peng Wang Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261023145101.8217-1-peng_wang@linux.alibaba.com --- kernel/time/tick-sched.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 6c3fea3867139..baa3ac9b48f88 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -400,9 +400,21 @@ static bool can_stop_full_tick(int cpu, struct tick_sched *ts) return true; } +static void tick_nohz_full_update_tick(struct tick_sched *ts); + static void nohz_full_kick_func(struct irq_work *work) { - /* Empty, the tick restart happens on tick_nohz_irq_exit() */ + struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); + + if (WARN_ON_ONCE(!tick_nohz_full_cpu(smp_processor_id()))) + return; + + /* Task-context flushes may not be followed by an IRQ exit. */ + if (!in_hardirq()) { + if (WARN_ON_ONCE(tick_sched_flag_test(ts, TS_FLAG_INIDLE))) + return; + tick_nohz_full_update_tick(ts); + } } static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = -- 2.53.0