From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 18C5519D07E for ; Tue, 15 Sep 2026 05:20:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789449624; cv=none; b=h6mOUUmMOuLaj7N37sRBglDXuQXdSBRtlvWdeN346ahwz6asEXWzegcGH9CP4hEqonKUEnlVXFu1/toIYYcduP/4ROb/hjVPrEuJF/e8keTqMgbZ04FRBlPanRdQoN6DSOG7Dzt0D0qxJvd80V6RAHmxbup8viTkNkLhJpHpiHk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789449624; c=relaxed/simple; bh=v2CCytaW6WiDwVywAEisOXbYBfQ13KjtbAR0hDBrp9w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=C6tkUFr74gSc1HC7Woa4GlbRFY1LZ8qWZGesQ0EkCbPRbjNFWScQZQpqQTOXqg9w7TiOG/nyXMC2WmHB6t10YJomNiVrqsl4JrwFtKJzUoBTbP1NTxrtAlGfyVfk2oFmFOrookutd+kIFWunbL5P7+xkFmt47MIsDxo7k+78+Hw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=IHllBFSq; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IHllBFSq" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=h7pZGtE1OlV9lUYg7yr1DTNsLeDD7r6CrCofCUZPUR0=; b=IHllBFSqkQ9F9jq5syBgwkFD3T uFtAfTdgsBV26bRQ6J5dGqdNUAsGS3+OyysEWNFdXr+08mm+pe8NfuZP4gd1eusF2Qdtj6I6K6AWm pNecjkoGsZjjRqM5gAFgBhP4LN4t0gfN1KZE7V3gBpXquIHskkwipP5imMDCGmW78pYAVrwNvLVM4 6dmgoQwO++pVHQPPqhGCp7tOFkAL0liDTSY2AuoCsQVj3qxMzTKQAykUdmr5kaSWUlnsi8BLy7mOP phS1UBqBcfXVWVsXADH9+txOUMJW65cAxLvhobNNwpFM/EiTiDck1FhvbsEthBXH4dN3dYCk+NMEk 2KXDajfA==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.2 #2 (Red Hat Linux)) id 1x6LZS-00000006HQN-3XZN; Tue, 15 Sep 2026 05:19:24 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 20CD73012C6; Tue, 15 Sep 2026 07:19:05 +0200 (CEST) Date: Tue, 15 Sep 2026 07:19:05 +0200 From: Peter Zijlstra To: Waiman Long Cc: Ingo Molnar , Will Deacon , Boqun Feng , linux-kernel@vger.kernel.org, Davidlohr Bueso , Haakon Bugge , David Laight , Linus Torvalds , Yafang Shao , Steven Rostedt Subject: Re: [PATCH] locking/osq_lock: Ensure proper locking semantics for osq_lock/osq_unlock() Message-ID: <20260915051905.GB776954@noisy.programming.kicks-ass.net> References: <20260910141908.592414-1-longman@redhat.com> <20260914112225.GA3500130@noisy.programming.kicks-ass.net> 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: On Mon, Sep 14, 2026 at 10:30:12PM -0400, Waiman Long wrote: > On 9/14/26 7:22 AM, Peter Zijlstra wrote: > > This doesn't make sense. You cannot argue that the code is correct as is > > and still add Fixes. > > That is true. I added this paragraph to show that it is not a serious bug, > but I still think it is better to fix it or we have to explicitly say that > it is not a real lock in term of how it can be used. I have taken it out to > avoid confusion. "It is not a real lock" will do. It has always been meant as a optimistic spin queue -- very much not a lock.