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 80729DDC1; Thu, 10 Jul 2025 04:06:10 +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=1752120372; cv=none; b=qB743XDFdINmjqGcDnTlh30ePsNh0OildweMLeBO3B7Arhq2WdvXSgzECNfsEZXWfB0UYWtVtyJZECljmf/AJcn/VMPG/cH44Mp/ZBGjd4Q+nh4JuXEdcuuJd/3B/faf3cc2YFNuNVRFj/5jfRh4ulMg5B6fTJ2XSLT8w4WuYGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752120372; c=relaxed/simple; bh=EOJvIJKcp1uaEI3Nv8Nu8Gfe2d92xfES/f4sTFodMkg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Mh++im0UDf0VKi/BqGtfvXJJGhBO0TP0yYf1zl7onrM9hEoseqP9by6pF2AhMBa7rHkfY/L5HXcq+5LY+wn4N7XZKERGKrRAr1Hx2u7Acq5l7WdyCrpLEfBZgY+4jm3Zk8LhcOSjsMV/AtknJ7H+bK/1i+yms0ZQwSZBAIzkQts= 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=SnApjbS1; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Skd/vG4r; 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="SnApjbS1"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Skd/vG4r" Date: Thu, 10 Jul 2025 06:06:07 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1752120368; 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: in-reply-to:in-reply-to:references:references; bh=MiGQOhHJzmi7Jd1WWo/0Ygq0kCc1gl9yVILzeL51PFE=; b=SnApjbS1/YX+oS4g8XRJfjTFWGsZzia5xtIieth5I6yuu71sa/sPkekyaJZ31hdAdHq7pO YR12N4ow+utaaLruRTVSmVvh1GdUrgF5iVXwA/1flcA05wORZlvh2/8LY4jzXAZJRMsrxe Nu6UlC2C8npaL0rsNhAWrFy9Vc60JZr58lygcUB0AJd/BTV6qiTnTks4OQQ29fq/oIZe+U Z2EQ/+WhYj0Vu+9AX82tWHcRm27bcBuRnsM1NdgOWaMUVlw2SeHsDRl+fF7wls7kBCpo2J SM+Ab9Wbzmw3kmvuy3iqOrQc2ISBsMrZ7Gm9BGiJwoBacLXWelPzHO/b1QVMJA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1752120368; 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: in-reply-to:in-reply-to:references:references; bh=MiGQOhHJzmi7Jd1WWo/0Ygq0kCc1gl9yVILzeL51PFE=; b=Skd/vG4rUwqi/EJmaHNXAMTkFbV8KycrfhGyvTXe9yudxnR9XOtzreimY4sbrkeOv7BIyX w9M/yazjnol1FlCQ== From: Nam Cao To: Xi Ruoyao Cc: Christian Brauner , Frederic Weisbecker , Valentin Schneider , Alexander Viro , Jan Kara , Sebastian Andrzej Siewior , John Ogness , Clark Williams , Steven Rostedt , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, linux-rt-users@vger.kernel.org, Joe Damato , Martin Karsten , Jens Axboe Subject: Re: [PATCH v3] eventpoll: Fix priority inversion problem Message-ID: <20250710040607.GdzUE7A0@linutronix.de> References: <20250527090836.1290532-1-namcao@linutronix.de> <20250701-wochen-bespannt-33e745d23ff6@brauner> <20250710034805.4FtG7AHC@linutronix.de> Precedence: bulk X-Mailing-List: linux-rt-users@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: <20250710034805.4FtG7AHC@linutronix.de> On Thu, Jul 10, 2025 at 05:48:08AM +0200, Nam Cao wrote: > On Thu, Jul 10, 2025 at 11:08:18AM +0800, Xi Ruoyao wrote: > > After upgrading my kernel to the recent mainline I've encountered some > > stability issue, like: > > > > - When GDM started gnome-shell, the screen often froze and the only > > thing I could do was to switch into a VT and reboot. > > - Sometimes gnome-shell started "fine" but then starting an application > > (like gnome-console) needed to wait for about a minute. > > - Sometimes the system shutdown process hangs waiting for a service to > > stop. > > - Rarely the system boot process hangs for no obvious reason. > > > > Most strangely in all the cases there are nothing alarming in dmesg or > > system journal. > > > > I'm unsure if this is the culprit but I'm almost sure it's the trigger. > > Maybe there's some race condition in my userspace that the priority > > inversion had happened to hide... but anyway reverting this patch > > seemed to "fix" the issue. > > > > Any thoughts or pointers to diagnose further? I fetched Linus's tree, and noticed that the latest commit in Linus tree fixes an use-after-free issue in eventpoll: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8c2e52ebbe885c7eeaabd3b7ddcdc1246fc400d2 Any chance it resolves your issue? Nam