From: jing zhang Subject: Re: [PATCH] ext4: memory leakage in ext4_mb_free_blocks() Date: Thu, 25 Mar 2010 22:09:38 +0800 Message-ID: References: <87d3ytd56l.fsf@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: linux-ext4 , "Theodore Ts'o" , Andreas Dilger , Dave Kleikamp To: "Aneesh Kumar K. V" Return-path: Received: from mail-gx0-f217.google.com ([209.85.217.217]:35766 "EHLO mail-gx0-f217.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753338Ab0CYOJj (ORCPT ); Thu, 25 Mar 2010 10:09:39 -0400 Received: by gxk9 with SMTP id 9so2151565gxk.8 for ; Thu, 25 Mar 2010 07:09:39 -0700 (PDT) In-Reply-To: <87d3ytd56l.fsf@linux.vnet.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: 2010/3/25, Aneesh Kumar K. V : > On Wed, 24 Mar 2010 21:55:55 +0800, jing zhang wrote: >> From: Jing Zhang >> >> Date: Wed Mar 24 21:54:22 2010 >> >> There is memory leakage in ext4_mb_free_blocks(), if error, double >> free of blocks, occurs in ext4_mb_free_metadata(). >> >> Cc: Theodore Ts'o >> Cc: Andreas Dilger >> Cc: Dave Kleikamp >> Signed-off-by: Jing Zhang >> >> --- >> >> --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800 >> +++ ext4_mm_leak/mballoc8.c 2010-03-24 21:46:50.000000000 +0800 >> @@ -4419,7 +4419,8 @@ ext4_mb_free_metadata(handle_t *handle, >> spin_lock(&sbi->s_md_lock); >> list_add(&new_entry->list, &handle->h_transaction->t_private_list); >> spin_unlock(&sbi->s_md_lock); >> - return 0; >> + /* info the caller new_entry is used */ >> + return 1; >> } >> > > return 0 on success and -1 on failure Agree > > >> /* >> @@ -4547,7 +4548,8 @@ do_more: >> >> ext4_lock_group(sb, block_group); >> mb_clear_bits(bitmap_bh->b_data, bit, count); >> - ext4_mb_free_metadata(handle, &e4b, new_entry); >> + if (0 == ext4_mb_free_metadata(handle, &e4b, new_entry)) >> + kmem_cache_free(ext4_free_ext_cachep, >> new_entry); > > I guess it would be better to be > > if (ext4_mb_free_metadat() == -1) > kmem_cache_free(..) Fine - zj > > > >> } else { >> /* need to update group_info->bb_free and bitmap >> * with group lock held. generate_buddy look at > > > -aneesh >