From patchwork Fri Feb 26 01:22:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 388429 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 DEB13C433E0 for ; Fri, 26 Feb 2021 01:23:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 90FB964EE2 for ; Fri, 26 Feb 2021 01:23:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230105AbhBZBXn (ORCPT ); Thu, 25 Feb 2021 20:23:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:53158 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230083AbhBZBX2 (ORCPT ); Thu, 25 Feb 2021 20:23:28 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DC90864F49; Fri, 26 Feb 2021 01:22:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614302552; bh=9D3MCTfUWcx8h6AOs9X1S6qRmekrACM7jyDIHxg84YY=; h=Date:From:To:Subject:In-Reply-To:From; b=ujsrM1VFch/lB8MicVYu4rRHFs/+bGmkxuHx2/xN3NCeFUCPjehlbs7jDO5B31L4a Y1Lk1v4Rgd+80FNBUDNtPGrXYDhOC8cUvxvbcB0x3iqsAhC8btHoMFZIBahL7dqET9 uNhpZCG3pT/cOSdDXiGNImClbUpsW6VtLsbKm4ZQ= Date: Thu, 25 Feb 2021 17:22:29 -0800 From: Andrew Morton To: akpm@linux-foundation.org, corbet@lwn.net, dave.hansen@linux.intel.com, davem@davemloft.net, linux-mm@kvack.org, lucien.xin@gmail.com, luto@kernel.org, marcelo.leitner@gmail.com, mingo@redhat.com, mm-commits@vger.kernel.org, neilb@suse.de, nhorman@tuxdriver.com, peterz@infradead.org, stable@vger.kernel.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, vyasevich@gmail.com Subject: [patch 113/118] x86: fix seq_file iteration for pat/memtype.c Message-ID: <20210226012229.S5QJUOJAz%akpm@linux-foundation.org> In-Reply-To: <20210225171452.713967e96554bb6a53e44a19@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: NeilBrown Subject: x86: fix seq_file iteration for pat/memtype.c The memtype seq_file iterator allocates a buffer in the ->start and ->next functions and frees it in the ->show function. The preferred handling for such resources is to free them in the subsequent ->next or ->stop function call. Since Commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") there is no guarantee that ->show will be called after ->next, so this function can now leak memory. So move the freeing of the buffer to ->next and ->stop. Link: https://lkml.kernel.org/r/161248539022.21478.13874455485854739066.stgit@noble1 Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") Signed-off-by: NeilBrown Cc: Xin Long Cc: Alexander Viro Cc: Andy Lutomirski Cc: Dave Hansen Cc: "David S. Miller" Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Marcelo Ricardo Leitner Cc: Neil Horman Cc: Peter Zijlstra Cc: Vlad Yasevich Cc: Signed-off-by: Andrew Morton --- arch/x86/mm/pat/memtype.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/mm/pat/memtype.c~x86-fix-seq_file-iteration-for-pat-memtypec +++ a/arch/x86/mm/pat/memtype.c @@ -1164,12 +1164,14 @@ static void *memtype_seq_start(struct se static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos) { + kfree(v); ++*pos; return memtype_get_idx(*pos); } static void memtype_seq_stop(struct seq_file *seq, void *v) { + kfree(v); } static int memtype_seq_show(struct seq_file *seq, void *v) @@ -1181,8 +1183,6 @@ static int memtype_seq_show(struct seq_f entry_print->end, cattr_name(entry_print->type)); - kfree(entry_print); - return 0; }