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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 6ABF1C43331 for ; Tue, 24 Mar 2020 13:25:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4170020775 for ; Tue, 24 Mar 2020 13:25:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585056340; bh=JSFuvJQzJ7z7qEnJYSNpQwGk9hUieakJek03WvMDRPI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZrCrvVrwKT0IL+vEhDeVR6MuhlitPXYg2OYaMw+kbefFa3M7gDYGYJjdneJ6XWEdi ipizEBI3HLdoCA3JbbQpvDh7NrfPWYxyHwO240u5iX0Vh+49oaZramrEWlC4D6zqut L9F26OzSp3GNyYYEuaeNfB9j828LjsAjW6hu0tyc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728821AbgCXNZe (ORCPT ); Tue, 24 Mar 2020 09:25:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:49856 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725767AbgCXNZe (ORCPT ); Tue, 24 Mar 2020 09:25:34 -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 D30AE208FE; Tue, 24 Mar 2020 13:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585056333; bh=JSFuvJQzJ7z7qEnJYSNpQwGk9hUieakJek03WvMDRPI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zwztQlbBaaM4heHB6SciBlnRK9eHbtWR4vDbQM0RqnBY76lMN/jZ4qGzCHXn9/ANr xNMng5gh9y7e6L4w3A55Y9M8DlROu68vQmisChubHL2ueA5zKC+SQLvIxNKwcI/u0E w4g0LiPzTLFp8V0Yl+ByTGOb1Sn2OU4xjQCogWiQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Weiner , Chris Down , Andrew Morton , Tejun Heo , Roman Gushchin , Michal Hocko , Nathan Chancellor , Linus Torvalds Subject: [PATCH 5.5 093/119] mm, memcg: fix corruption on 64-bit divisor in memory.high throttling Date: Tue, 24 Mar 2020 14:11:18 +0100 Message-Id: <20200324130817.468739261@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200324130808.041360967@linuxfoundation.org> References: <20200324130808.041360967@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chris Down commit d397a45fc741c80c32a14e2de008441e9976f50c upstream. Commit 0e4b01df8659 had a bunch of fixups to use the right division method. However, it seems that after all that it still wasn't right -- div_u64 takes a 32-bit divisor. The headroom is still large (2^32 pages), so on mundane systems you won't hit this, but this should definitely be fixed. Fixes: 0e4b01df8659 ("mm, memcg: throttle allocators when failing reclaim over memory.high") Reported-by: Johannes Weiner Signed-off-by: Chris Down Signed-off-by: Andrew Morton Acked-by: Johannes Weiner Cc: Tejun Heo Cc: Roman Gushchin Cc: Michal Hocko Cc: Nathan Chancellor Cc: [5.4.x+] Link: http://lkml.kernel.org/r/80780887060514967d414b3cd91f9a316a16ab98.1584036142.git.chris@chrisdown.name Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2339,7 +2339,7 @@ void mem_cgroup_handle_over_high(void) */ clamped_high = max(high, 1UL); - overage = div_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT, + overage = div64_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT, clamped_high); penalty_jiffies = ((u64)overage * overage * HZ)