From mboxrd@z Thu Jan 1 00:00:00 1970 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 E755B3AF65F for ; Sat, 5 Sep 2026 20:59:56 +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=1788641998; cv=none; b=SKlMByTV/AlSD2FCbKIxOkHLT9auRt6rDyLgMwj71O1WsUqej7by+ve6aFCR/NC4uey/JRSXdYU+uiiPLgJQwwCxvWHZvuGq9M5Zb2NKEmAnoTVTdJyaDCculLvAp67AZ1e664D0AYsPYPU4k2VbwEhTtPJRMDj8VTD6ouAu8JA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788641998; c=relaxed/simple; bh=twyl2qgEIyr5Z7GpQCf9DFBtoqwwwqhoTARFl8uEWhg=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=kKRgNdYQ1j9YkhagRfehBF1wHp9v6YITGNEx5bfbuBgFNnj+I4MMCLSLbooI6Q31fK+905N/BOnP7rKrsDzlCDttJeKWcVH9Tp2NwcRFdlM97JAvKDHklVzdnuHYf901YO8/M92A6ahBgi65dZlVNiXVM0vcsJfj2z2FBCs2ggQ= 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=34/FBdq7; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=ByU317QT; 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="34/FBdq7"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="ByU317QT" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1788641995; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VTgLcjds5+GkcAXbUF2ZY5BHTT1h73DRe7LhwxjyTgs=; b=34/FBdq7IPv3MBSupdIX6H0YEzNWEt8jUFi0FGiu1BwKjbUcEursUADLz6cpY6NxZnzy74 2CQAFUrlaFJUoY9bchbxTom2L7spACPy2CZ5/0/z2X8WZaowOT+Ua2h9USaPOenNQXqFaZ 9XDklsqtZjFAKfQOsybFn3qXpBiu46+6CzY0C40UEhxIk3h8BDK3dxP2FBvDQOTpIPcKzZ aE4cSy1u9zxfuqywMBwORDv/x+fPR4hwHE+T2W8bm7UD5edlQnFDEeWPD2y7BOlumOkMBz IBq85kAAqgo9zPmoa9QHD9+sXaj95t/vHIeUI0YDsW3bC03x3wO7LnzbvVRAkg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1788641995; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VTgLcjds5+GkcAXbUF2ZY5BHTT1h73DRe7LhwxjyTgs=; b=ByU317QTSI4wQS68QB9ZTfDEF6IOMQshTKRppHV4dQOFLVT6nJyz81Gy2HrZk44UUyMBkX bRPOZwRUPKHHCzBg== To: =?utf-8?B?5YiY5pyv6auY?= , =?utf-8?B?5pyx5oG6?= =?utf-8?B?5Lm+?= , Daniel Lezcano , =?utf-8?B?5byg5ZiJ5Lyf?= Cc: "linux-kernel@vger.kernel.org" , =?utf-8?B?546L6Z+s?= , =?utf-8?B?54aK5Lqu?= , "isaacmanjarres@google.com" , Frederic Weisbecker , Anna-Maria Behnsen , =?utf-8?B?5qKB5Lyf6bmP?= , =?utf-8?B?57+B6YeR6aOe?= Subject: Re: =?utf-8?B?5Zue5aSNOg==?= [External Mail][PATCH] tick/broadcast: Plug clockevents replacement race In-Reply-To: <6eb4fac303f4457f9686510664e79bff@xiaomi.com> References: <042520850d394f0bb0004a226db63d0d@xiaomi.com> <87o77m1v9r.ffs@tglx> <835d5847-1aa0-4852-89c7-6a6996b3eb65@linaro.org> <87o775uh0y.ffs@tglx> <87frrs8lsg.ffs@tglx> <87cymdsu0r.ffs@tglx> <6eb4fac303f4457f9686510664e79bff@xiaomi.com> Date: Sat, 05 Sep 2026 22:59:54 +0200 Message-ID: <87o6eb4do5.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Fri, Aug 28 2026 at 09:08, =E5=88=98=E6=9C=AF=E9=AB=98 wrote: Can you please adhere to the kernel mailing list netiquette: https://people.kernel.org/tglx/notes-about-netiquette > We have verified this patch on our platform (kernel v6.18 / Android 17) > and can confirm it resolves the race condition issue. The problem is that > tick_install_broadcast_device() calls clockevents_exchange_device() to > move the old device to the released list (setting it to DETACHED state), > then updates tick_broadcast_device.evtdev to the new device =E2=80=94 but= this > sequence is not protected by tick_broadcast_lock. The cpuidle/hrtimer > paths can observe the old device in DETACHED state during this window, > leading to unexpected behavior. > > After applying the patch, the issue no longer reproduces under our > concurrent CPU idle + clockevent device registration testing. > > Could you please share the expected timeline for merging this fix into > the mainline kernel? We have downstream products depending on this fix > and would appreciate it if the merge could be expedited. > > Test environment: > - Kernel: 6.18 > - Platform: Android 17 > - Test: Concurrent CPU idle + clockevent device registration and to the documented process in Documentation/process/* which clearly states that the way to confirm that a bug is fixed is expressed by a Tested-by: .... tag, which allows tools to pick it up automatically. Thanks, tglx