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 9077BC433FE for ; Tue, 5 Apr 2022 09:52:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345731AbiDEJny (ORCPT ); Tue, 5 Apr 2022 05:43:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239600AbiDEIUP (ORCPT ); Tue, 5 Apr 2022 04:20:15 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27AEC83; Tue, 5 Apr 2022 01:17:12 -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 ams.source.kernel.org (Postfix) with ESMTPS id C9394B81BB2; Tue, 5 Apr 2022 08:17:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22650C385A1; Tue, 5 Apr 2022 08:17:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649146629; bh=3KGFa6EC32xjqdgLhOOEcMv8VXMCN8d2FHi3RO5nQi4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K30RS9orHTn9vFLpPPhw5nkiFmcumWemH7adAwikgpvgooT4380kxTgMYTdA85Bq1 qRHvkZC6xJVtjjAd68LYLxUNIyRca+F5JV6HHg/QdqAdMFV3r+QedADyasQnSPfIqB z+/nNHOyNTjAWpQ0gE7K/FP7twVqap5Ftv4Tolv4= 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 5.17 0832/1126] fs: fix fd table size alignment properly Date: Tue, 5 Apr 2022 09:26:19 +0200 Message-Id: <20220405070431.979689181@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@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 c01c29417ae6..ee9317346702 100644 --- a/fs/file.c +++ b/fs/file.c @@ -303,10 +303,9 @@ 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