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=-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 1420EC5519F for ; Wed, 25 Nov 2020 08:05:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CAB720872 for ; Wed, 25 Nov 2020 08:05:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=natalenko.name header.i=@natalenko.name header.b="vM8tr4dL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726463AbgKYIFG (ORCPT ); Wed, 25 Nov 2020 03:05:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726317AbgKYIFF (ORCPT ); Wed, 25 Nov 2020 03:05:05 -0500 X-Greylist: delayed 38431 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 25 Nov 2020 00:05:05 PST Received: from vulcan.natalenko.name (vulcan.natalenko.name [IPv6:2001:19f0:6c00:8846:5400:ff:fe0c:dfa0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7100EC0613D4 for ; Wed, 25 Nov 2020 00:05:05 -0800 (PST) Received: from mail.natalenko.name (vulcan.natalenko.name [IPv6:fe80::5400:ff:fe0c:dfa0]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by vulcan.natalenko.name (Postfix) with ESMTPSA id 2ECA08AB47A; Wed, 25 Nov 2020 09:05:02 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1606291502; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zvcW9HZaeh1OandD5GIG39Q2Ayk1GgjH3J6qCgDWOJw=; b=vM8tr4dL6fv0m7XBgouKQNyYgrzoVJ+S3IiBMJqx9qJ/88tpWX0ZzHYs7Tfw7b4kXYPp+C R4pNvyP6feDj6a47yQUFhOLwZx5G+RjzwiRwjkk8xVX6fN8TahOlxEVJDi2OCY7yJWQBNb LWuWNT01K4XkzrXOCr3RXVlWn1XkD5o= MIME-Version: 1.0 Date: Wed, 25 Nov 2020 09:05:02 +0100 From: Oleksandr Natalenko To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, jk@ozlabs.org, mjg59@google.com, David.Laight@aculab.com, Vamshi K Sthambamkadi , stable@vger.kernel.org, Greg Kroah-Hartman Subject: Re: [PATCH] efivarfs: revert "fix memory leak in efivarfs_create()" In-Reply-To: <20201125075303.3963-1-ardb@kernel.org> References: <20201125075303.3963-1-ardb@kernel.org> User-Agent: Roundcube Webmail/1.4.9 Message-ID: <97016e69314d90aef859ae6d98e4bb9c@natalenko.name> X-Sender: oleksandr@natalenko.name Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Hello. On 25.11.2020 08:53, Ard Biesheuvel wrote: > The memory leak addressed by commit fe5186cf12e3 is a false positive: > all allocations are recorded in a linked list, and freed when the > filesystem is unmounted. This leads to double frees, and as reported > by David, leads to crashes if SLUB is configured to self destruct when > double frees occur. > > So drop the redundant kfree() again, and instead, mark the offending > pointer variable so the allocation is ignored by kmemleak. > > Cc: Vamshi K Sthambamkadi Should also have: Cc: # v5.9 > Fixes: fe5186cf12e3 ("efivarfs: fix memory leak in efivarfs_create()") > Reported-by: David Laight > Signed-off-by: Ard Biesheuvel > --- > fs/efivarfs/inode.c | 1 + > fs/efivarfs/super.c | 1 - > 2 files changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c > index 96c0c86f3fff..38324427a2b3 100644 > --- a/fs/efivarfs/inode.c > +++ b/fs/efivarfs/inode.c > @@ -103,6 +103,7 @@ static int efivarfs_create(struct inode *dir, > struct dentry *dentry, > var->var.VariableName[i] = '\0'; > > inode->i_private = var; > + kmemleak_ignore(var); > > err = efivar_entry_add(var, &efivarfs_list); > if (err) > diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c > index f943fd0b0699..15880a68faad 100644 > --- a/fs/efivarfs/super.c > +++ b/fs/efivarfs/super.c > @@ -21,7 +21,6 @@ LIST_HEAD(efivarfs_list); > static void efivarfs_evict_inode(struct inode *inode) > { > clear_inode(inode); > - kfree(inode->i_private); > } > > static const struct super_operations efivarfs_ops = { -- Oleksandr Natalenko (post-factum)