From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 5CB654A32; Thu, 20 Aug 2026 08:49:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787215781; cv=none; b=fse0vT9+M14UUwkPp51bMXciNCyYUnLum/zFFrJBk+FB7EWCKmhWGiGuwLBuDCgWZJK1gCJha6mOtjXrDII2G04NXutEimd6FyUdopOReZOnQPAIq3vMmI/JAhOK4vZImanhnd/Bofvk9kHLHYAwAqsFixya/BXlkWnQDxphAm0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787215781; c=relaxed/simple; bh=ZMLa3JcB5tSsjYVZl0BpBNNpOSfPEiUMh7fdTEaN67w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qQx1Uo57MAsd9gHI9eN9wfAkW/jjaGr2ih1gra/Hlvfdit420KjxFLViz68xkl2A8HbW10haxL4pOVY3TizdOS+tlM/zaOk2OqnoU7htreuCyZQFFwSWXzmdvp8NsRhTwJifySt8JD/g0MvlDWV1YRtIo/yIdokj8SjD2totocM= 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=E/tMM9LT; arc=none smtp.client-ip=90.155.50.34 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="E/tMM9LT" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=6jxfOD4bOvRu3R+XpcygwKPVmZ/VUDro80ay2eMAlY4=; b=E/tMM9LT8i+YrEpaq5NGEmVVfR +ubiJSSI28zHSuOkh+IDZEXppXw1rS7X6HfNY4tdO7s03GOk0C9CNw8JniV1zY6Tun9wROJU9q7yG g576mYxu73oJdnAkLNdegn5YFscTbLISZGZxPlO+DV5kfiyrL5lcpSn8KYqPTBxFLBIsy6er3uYeG pL4G/xc4rCEokuXL8dIeWoyHDAYYm4gf3Ck2xfPPweIJHfHGvewMnbRNlRPDdCjQjX+sQtkskldVr BHVjTFIBdkhlsj62iwOgdXX8IFQVtj/OUt9QC632q+qQkc8sO9GDlxkNTX4hUOggAnXQCMDz6xgoG nAYC7ymw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwySt-0000000FCp3-0Cb6; Thu, 20 Aug 2026 08:49:35 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id A46A13006FA; Thu, 20 Aug 2026 10:49:33 +0200 (CEST) Date: Thu, 20 Aug 2026 10:49:33 +0200 From: Peter Zijlstra To: Miklos Szeredi Cc: Sergey Senozhatsky , fuse-devel@lists.linux.dev, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2] fuse: permit freezing while waiting for request answer Message-ID: <20260820084933.GA4036497@noisy.programming.kicks-ass.net> References: <20260819023542.561653-1-senozhatsky@chromium.org> Precedence: bulk X-Mailing-List: linux-fsdevel@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 Wed, Aug 19, 2026 at 12:03:32PM +0200, Miklos Szeredi wrote: > Why is this unsafe exactly? Does that unsafeness apply to > filesystems? If so why do we allow freezing while blocked on > sb_start_write()? Getting frozen with lock A held, while another task is blocked on A in an unfreezable state results in the system not being freezable. IOW you deadlock the freeze.