From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=193.142.43.55 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794580335; b=HnY7VEw2kUNfpm4im3tvpUwB1F5OvJKkF0L7YaAzZ6qnkitBYIxhapTHgDBJcKryK/8f rXnout/ZvnW25tEg9JUl8bFk7TajUJcY6oidRCLi0gNtK4MBL+3wL4hP3eUVULeQydHpe kMT9IV0gPK7sZz62Diw16R/379TEKqCArfhJm1hBmZjzzwz1/nIvSRclS78P6PaACqZvy EygAl7fRFsdOd/scFRvXfL8B7B3rZdv6YXEjwCHjBH+8q5zsCS4wAnbkfJtiWf6LALBt5 2KdYtBUeAxS80dnu5esSC8ar/3jM4xu8DgOUUlHAZWw6kqHzsDJUlt6dwoNpq+6UoIg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794580335; h=DMARC-Filter:From:DKIM-Signature:DKIM-Signature:To:Cc:Subject: In-Reply-To:References:Date:Message-ID:MIME-Version:Content-Type; bh=FawFiCHhFqUP9UVTI9o6jUdPle4gc8XgnzAN35Imzwc=; b=MP7ZueCYe5vRHz5OvxEZUo6gO1zs8TDq6q2QpG6NAo8ahIKtBrn9SVQgeGR14DahpqRd XEZ74cYd+nwzD6ymdcUE2yNPuNTwgh4qs41ChN6V2sPywQoFQ9X+JHvh79ExyWxRTthPV TTlhGzd6IY+a/SI5IdAuBX1ob2RVDHFNqPnELaUzTutnp+8HuC05lruAD3wZ6iiVRhYdg PnD6SYlDk1vrvtkQ1B+lAOgi17glBcJ2O0xbTlmb/RPDxnJPDrYuuvAvR7zc9hIeCTJMn 4EaoLBxNxIYuX6JANchvbyHcoAdaSufQm73h7ams1uI2eMRP77jGVlwoHrz2PhE/poA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=PQrISobI; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=Ecffbj2f; arc=none smtp.remote-ip=193.142.43.55 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5038A606A32D for ; Fri, 13 Nov 2026 14:32:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5038A606A32D 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.a=rsa-sha256 header.s=2020 header.b=PQrISobI; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=Ecffbj2f From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1794580329; 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=FawFiCHhFqUP9UVTI9o6jUdPle4gc8XgnzAN35Imzwc=; b=PQrISobIqobQMqgflVE/f85lal3u8dJCwS/CL3KqviSq5ihVlt9Y742RnUL9yJrPaRolMr wPJQUBVfacmtwb6NmWxhyKJESKgUpmF8fOcMdTfNsvD5prurfrybdePC4hTula20Cryg4p 3TIyVCr35oT2j8T4yP9HrZKWyct9Nbg4J+iTuOlwDJ6zBv3H1Ome+m1AY9DaPCCVpsgxNa ATn4MoR0oodiM2Zr+vbct0Ywa/+6U7+/41ogCQdrDdZxFiJjrXNT0H+ad426uauUCPhTwG Nr9cERLU77onu5zKMYDgIKtDdeSeZnPFcQCWEoxQwekI95v/K+Eb0SR1kdT8YA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1794580329; 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=FawFiCHhFqUP9UVTI9o6jUdPle4gc8XgnzAN35Imzwc=; b=Ecffbj2fAeatwWRbgH3t9FI/sbWOSUEY7y6g0uL2vvz4PwJF/a5r6EVgc/r9fNxCpEB6+e ni10FdKZD4Gu4LBg== To: Mathieu Desnoyers , Peter Zijlstra , Jiakai Xu Cc: Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/mmcid: Bound the CID allocation busy wait In-Reply-To: References: <20260918013454.1850369-1-xujiakai24@mails.ucas.ac.cn> <20260918104349.GL776954@noisy.programming.kicks-ass.net> <877bjiem45.ffs@fw13> <87mrs8bhp4.ffs@fw13> Date: Fri, 13 Nov 2026 15:32:09 +0100 Message-ID: <87eccossye.ffs@fw13> X-Mailing-List: linux-kernel@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 On Wed, Nov 11 2026 at 20:48, Mathieu Desnoyers wrote: > On Tue, Oct 20 2026 at 15:54, Thomas Gleixner wrote: > I have a reproducer for a lockup that starts from the stale state you > describe. It needs two more things: the execve() fails, and the task is > moved to another CPU during that execve(). That has been reported already privately to me and a few others and the reporter provided a similar patch as you. While both variants seem simpler, I prefer the explicit re-initialization for the failed exec() case. It's a NOOP for newly initialized MMs and avoids the pointless fixup dance for the last user in the common case. Thanks, tglx