From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 0060B288C23 for ; Thu, 8 May 2025 19:59:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746734361; cv=none; b=kks3mBJfAPBxvcYW9zAtF9tLNBr3dYC972FwLLJPUAbaB0d/DKPdFDNmJ6+OB3gaAWO5Jh3XSFemmhpzAnBBwUwoS2ny8dKe/xxAmUn6YRO5eDa6C1JnpVQTzytuwNI1QjNaTAsEQJZD8BBXb66l1yGnOgesYQgkXfk68vR/LUU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746734361; c=relaxed/simple; bh=2z4khigyoAhC5KNlPeu+YZs6YzfxwiQWR2tgE/Ov2C0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nCof9xtvDu3ITHY1YIxhv6th+sVjs58PQBXODqAp7zHvJLW/YY9yU5KTMiCV23L+koaveV048fB0IeFK2+Vbhw6OQ2dwNLJtSEeYzr+6Khye8vBmCeR4GL0fDOiH0rZbDuMB1A82kjJiY8QwfKt4XFXzjGwIhKB0baPIkJeXKpk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=G/HNkgA9; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="G/HNkgA9" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=gRvKtN7Bjo+XxrtDIysDBDKxsS2+dP725UWkUeymprY=; b=G/HNkgA9MsLufCH60xl+HoNOdn 8Wo+Ai96TuoXn3w4rkAH0cGFUxR1lCgHN93wzKn+HLmYndyMiRqUf5arogzHZ6fQe4MChgzBmhSC6 yhSSUT+X3te7irGA3+36ZaoXytwpSKcdEDtFEr4XkYU4D+deddhtOpBE6pwBJIMyVCh+6z6LRFr8e nZElpuuQDcj7UgqVXrJtiZT6eReAtU0xLNzfOOwGFrbjD0ptmTSS/NPik4ukq2gpo+OfM9V13uaPJ sfM7XrmuPr3cDiw5/6oBbvB1HlH6jqO6sOAqAoJWbvS23GvUEDPWLVE4yS8J/dyXSKReSkxn3tONG pOyqy8fw==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uD7Om-00000007pQr-3QSy; Thu, 08 May 2025 19:59:16 +0000 Date: Thu, 8 May 2025 20:59:16 +0100 From: Al Viro To: Christian Brauner Cc: linux-fsdevel@vger.kernel.org, Linus Torvalds Subject: Re: more breakage there (was Re: [RFC] move_mount(2): still breakage around new mount detection) Message-ID: <20250508195916.GC2023217@ZenIV> References: <20250428063056.GL2023217@ZenIV> <20250428070353.GM2023217@ZenIV> <20250428-wortkarg-krabben-8692c5782475@brauner> <20250428185318.GN2023217@ZenIV> <20250508055610.GB2023217@ZenIV> 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: <20250508055610.GB2023217@ZenIV> Sender: Al Viro On Thu, May 08, 2025 at 06:56:10AM +0100, Al Viro wrote: > I'll cook something along those lines (on top of "do_move_mount(): don't > leak MNTNS_PROPAGATING on failures") and if it survives overnight tests > post it tomorrow^Win the morning... Got it. Pushed out to viro/vfs.git#fixes; just 4 commits there at the moment - 1) __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock 2) do_umount(): add missing barrier before refcount checks in sync case 3) do_move_mount(): don't leak MNTNS_PROPAGATING on failures 4) fix IS_MNT_PROPAGATING uses I've got reliable reproducers for #3 and #4, but they'll probably need to be massaged for kselftests - any help with that would be very welcome. Patches and those two reproducers in followups; please review and test.