From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8BC75409285; Fri, 31 Jul 2026 17:40:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785519648; cv=none; b=Osm91P9j/Q3+XKzSBw1ksh8kFsil8zSIgDXO4R+L4jlC1TrudPHi8NE/eTI0VFq5kojNOER8d460P/vEXV+CGlBUKeA/Bs2sSuJCUzRNCwsl1i3bt/C9viOkK0ZqmRP5PoNPU1uNMkPgdr0s+oweTD/ZIID/N0OdChUJkfLSt14= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785519648; c=relaxed/simple; bh=TGoQMj+p+jdX6QqY32pVurptGVJZn2A+i3IdSmbwLTA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JB+8ujLDL7HpZYnuymz8i9c1tm13QlqKZdRjBc9azWN500doAhyksvENfoX8vJFO7xeg0iiZLby/iUmS2zjdkDDWDhRcbp6M4TMGSxudjfZXUoU4GfIl6oyrZ5hLoRuM9gxl8UuuDlJUOZOWdvhWjIdeGuS7ws4wu/XvGoJ16DU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZyopIUCw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZyopIUCw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB0261F00AC4; Fri, 31 Jul 2026 17:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785519644; bh=xOsZNPiZLrwsRyYuSDTurRc4UKWa981GtnO5vLqQRAw=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To; b=ZyopIUCwH0WFQ8uaT4qz2R5CUC4WY1idI8Yac8qFsF92fbLCW4Y1WP8cO05xCL8dT EJjFmQDbWyLmYgQdtD6DzNWFLuRY6gM8+ygj/VeASmH+o37ETTTyNeI5UQI7ty1dER BIIbEQKVNEbyYqUPcKdaCstSXJ4aeYJ0ov/DmKnbXFoF+6na4FZXwzdQRXrPlIcBGQ Yqb2ZvggASq+lZ/QLDUQ3LHQJHdR5hP47yDZjRP+GCv4nnrlkBGS7MKFgzRkCbuIQj fuvirJyBI78fcH4krHUtBSKTJsf/8MATFUNysQCrbx8EsE5hg++MQ03FEoVeTp0+dO 20zSB9v45Yhqw== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 97E60CE0E98; Fri, 31 Jul 2026 10:40:44 -0700 (PDT) Date: Fri, 31 Jul 2026 10:40:44 -0700 From: "Paul E. McKenney" To: Christian Brauner Cc: Anna-Maria Behnsen , Frederic Weisbecker , Thomas Gleixner , "Peter Zijlstra (Intel)" , linux-kernel@vger.kernel.org, kernel-team@meta.com, Benjamin LaHaise , Alexander Viro , Jan Kara , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH RFC 2/9] aio: Use accessor for hrtimer_sleeper ->task field Message-ID: <0f8ddd97-89e1-45c8-a779-e56adcde4098@paulmck-laptop> Reply-To: paulmck@kernel.org References: <20260731004019.3530210-2-paulmck@kernel.org> <20260731-ritzen-ratgeber-fastnacht-519674d2de1d@brauner> 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=us-ascii Content-Disposition: inline In-Reply-To: <20260731-ritzen-ratgeber-fastnacht-519674d2de1d@brauner> On Fri, Jul 31, 2026 at 02:57:57PM +0200, Christian Brauner wrote: > On 2026-07-30 17:40 -0700, Paul E. McKenney wrote: > > The hrtimer_sleeper structure's ->task field is used as a flag to indicate > > that the associated hrtimer has expired. This means that the hrtimer > > handler can be storing to this field while other code is loading from it > > to check for expiry. Note that additional races appear for hrtimers that > > can be restarted, which could be argued to be a user error. However, that > > is no reason to let the compiler introduce additional confusion, and to > > this end, the hrtimer_sleeper_task_get() was introduced, use of which also > > has the benefit of avoiding open-code access to hrtimer_sleeper innards. > > > > KCSAN located this issue. > > > > Signed-off-by: Paul E. McKenney > > Cc: Benjamin LaHaise > > Cc: Alexander Viro > > Cc: Christian Brauner > > Cc: Jan Kara > > Cc: Anna-Maria Behnsen > > Cc: Frederic Weisbecker > > Cc: Thomas Gleixner > > Cc: > > Cc: > > --- > > Reviewed-by: Christian Brauner (Amutable) Thank you both, and I will apply your tags on my next rebase. Thanx, Paul