From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E536BC433F5 for ; Tue, 5 Apr 2022 21:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1385059AbiDEVs5 (ORCPT ); Tue, 5 Apr 2022 17:48:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243531AbiDEKgv (ORCPT ); Tue, 5 Apr 2022 06:36:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C323954FA9; Tue, 5 Apr 2022 03:22:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 519A7617CC; Tue, 5 Apr 2022 10:22:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66C0BC385A1; Tue, 5 Apr 2022 10:22:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649154148; bh=3m/KIQ3dfU4W25SXZqENH+2s+cwiIgEtA775dYS6wko=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=po2NxxiQlzd/qTf00P+HSd5b9VeHRLgwHYC0fKQNFyzw5j889sSOn11KNASkt8BeU 5naJkC0/5Etenqc8188uUAcxIJP3EXR6sPuQK6HSqJoZ2UDku+sUbHdDCdEePDmiX2 OIVFpMeYEop8dwI13u31OLlyalS37vIeX4pLxsG8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Fedor Pchelkin , Alexey Khoroshilov , Christian Brauner , Linus Torvalds , Sasha Levin , "Jason A . Donenfeld" Subject: [PATCH 5.10 448/599] fs: fix fd table size alignment properly Date: Tue, 5 Apr 2022 09:32:22 +0200 Message-Id: <20220405070312.161043627@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070258.802373272@linuxfoundation.org> References: <20220405070258.802373272@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds [ Upstream commit d888c83fcec75194a8a48ccd283953bdba7b2550 ] Jason Donenfeld reports that my commit 1c24a186398f ("fs: fd tables have to be multiples of BITS_PER_LONG") doesn't work, and the reason is an embarrassing brown-paper-bag bug. Yes, we want to align the number of fds to BITS_PER_LONG, and yes, the reason they might not be aligned is because the incoming 'max_fd' argument might not be aligned. But aligining the argument - while simple - will cause a "infinitely big" maxfd (eg NR_OPEN_MAX) to just overflow to zero. Which most definitely isn't what we want either. The obvious fix was always just to do the alignment last, but I had moved it earlier just to make the patch smaller and the code look simpler. Duh. It certainly made _me_ look simple. Fixes: 1c24a186398f ("fs: fd tables have to be multiples of BITS_PER_LONG") Reported-and-tested-by: Jason A. Donenfeld Cc: Fedor Pchelkin Cc: Alexey Khoroshilov Cc: Christian Brauner Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/file.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/file.c b/fs/file.c index a47a1edb9404..8431dfde036c 100644 --- a/fs/file.c +++ b/fs/file.c @@ -301,10 +301,9 @@ static unsigned int sane_fdtable_size(struct fdtable *fdt, unsigned int max_fds) unsigned int count; count = count_open_files(fdt); - max_fds = ALIGN(max_fds, BITS_PER_LONG); if (max_fds < NR_OPEN_DEFAULT) max_fds = NR_OPEN_DEFAULT; - return min(count, max_fds); + return ALIGN(min(count, max_fds), BITS_PER_LONG); } /* -- 2.34.1