From patchwork Mon Mar 1 16:14:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 389706 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 957DFC433DB for ; Mon, 1 Mar 2021 18:24:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 688F464DE0 for ; Mon, 1 Mar 2021 18:24:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239713AbhCASYg (ORCPT ); Mon, 1 Mar 2021 13:24:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:39422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239742AbhCASTM (ORCPT ); Mon, 1 Mar 2021 13:19:12 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 263DC64FEA; Mon, 1 Mar 2021 17:01:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614618085; bh=I7b3yx0/3AZbOcviqFG98A7cHcB/OI0fO55jul6wvmA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=roo5nbGaPac1SB1N4ZEclvFsfP50oGqcP0nlumWjiTzysKxjjgK4Xygi1+JWyfJ2A yqc9GYpcEX2aba1NgBuXF4mkpyT+/KBSoisZvNY66jhKXk2IEQBcba+EtbaoQvQBuL ie0yCE0KRGtFbyTSv5uVHv0k1wm4K1cETCIrttPo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, NeilBrown , Xin Long , Alexander Viro , Andy Lutomirski , Dave Hansen , "David S. Miller" , Ingo Molnar , Jonathan Corbet , Marcelo Ricardo Leitner , Neil Horman , Peter Zijlstra , Vlad Yasevich , Andrew Morton , Linus Torvalds Subject: [PATCH 5.4 302/340] x86: fix seq_file iteration for pat/memtype.c Date: Mon, 1 Mar 2021 17:14:06 +0100 Message-Id: <20210301161103.143469276@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161048.294656001@linuxfoundation.org> References: <20210301161048.294656001@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: NeilBrown commit 3d2fc4c082448e9c05792f9b2a11c1d5db408b85 upstream. 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 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/pat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -1132,12 +1132,14 @@ 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) @@ -1146,7 +1148,6 @@ static int memtype_seq_show(struct seq_f seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type), print_entry->start, print_entry->end); - kfree(print_entry); return 0; }