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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B473C433FF for ; Fri, 2 Aug 2019 09:47:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA7BE206A2 for ; Fri, 2 Aug 2019 09:47:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739231; bh=ub2i0odmx7m8MQjRuWxJMi/W74+GzzJ3ZvokLiAy6yo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HUGRg4Lc70ADHkxpN4X9mg1xbB58Pur88OTQRu/D9SqnfRSdfCFUzUyLmtqKZ8UPw BiTjayrcSLEm1ZmU0/QvOx59DoIunod2NZ4Tv4D/mXZjqL6ZChDDhXweemIk+iAaRQ IwaqIBiFo3T3SHDvlxIVELlefa+PpjxHa+pO7YwI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405590AbfHBJrH (ORCPT ); Fri, 2 Aug 2019 05:47:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:51686 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391836AbfHBJrB (ORCPT ); Fri, 2 Aug 2019 05:47:01 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B0AE22086A; Fri, 2 Aug 2019 09:46:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739220; bh=ub2i0odmx7m8MQjRuWxJMi/W74+GzzJ3ZvokLiAy6yo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aD/S7HUl9rDpBBlEI/uF3eAlWn0bIxAGnrQymTK1zLIzLvKDe+fmEfBkltbNMegD0 5XmsSftpqgj1VVpLWlVgbIAm7jD+7Bpsy1/GP9+bmVTZ7jBXwte47cNqojsHOozQRc QBKYtTVO2jnPa9uwCwWujB4i0Uqbb6LoUkD16IV0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Menzel , "J. Bruce Fields" , Sasha Levin Subject: [PATCH 4.9 158/223] nfsd: Fix overflow causing non-working mounts on 1 TB machines Date: Fri, 2 Aug 2019 11:36:23 +0200 Message-Id: <20190802092248.512740385@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 3b2d4dcf71c4a91b420f835e52ddea8192300a3b ] Since commit 10a68cdf10 (nfsd: fix performance-limiting session calculation) (Linux 5.1-rc1 and 4.19.31), shares from NFS servers with 1 TB of memory cannot be mounted anymore. The mount just hangs on the client. The gist of commit 10a68cdf10 is the change below. -avail = clamp_t(int, avail, slotsize, avail/3); +avail = clamp_t(int, avail, slotsize, total_avail/3); Here are the macros. #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) `total_avail` is 8,434,659,328 on the 1 TB machine. `clamp_t()` casts the values to `int`, which for 32-bit integers can only hold values −2,147,483,648 (−2^31) through 2,147,483,647 (2^31 − 1). `avail` (in the function signature) is just 65536, so that no overflow was happening. Before the commit the assignment would result in 21845, and `num = 4`. When using `total_avail`, it is causing the assignment to be 18446744072226137429 (printed as %lu), and `num` is then 4164608182. My next guess is, that `nfsd_drc_mem_used` is then exceeded, and the server thinks there is no memory available any more for this client. Updating the arguments of `clamp_t()` and `min_t()` to `unsigned long` fixes the issue. Now, `avail = 65536` (before commit 10a68cdf10 `avail = 21845`), but `num = 4` remains the same. Fixes: c54f24e338ed (nfsd: fix performance-limiting session calculation) Cc: stable@vger.kernel.org Signed-off-by: Paul Menzel Signed-off-by: J. Bruce Fields Signed-off-by: Sasha Levin --- fs/nfsd/nfs4state.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index c4762d8aa9f8..032fcae3a94f 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1511,7 +1511,7 @@ static u32 nfsd4_get_drc_mem(struct nfsd4_channel_attrs *ca) * Never use more than a third of the remaining memory, * unless it's the only way to give this client a slot: */ - avail = clamp_t(int, avail, slotsize, total_avail/3); + avail = clamp_t(unsigned long, avail, slotsize, total_avail/3); num = min_t(int, num, avail / slotsize); nfsd_drc_mem_used += num * slotsize; spin_unlock(&nfsd_drc_lock); -- 2.20.1