Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750905AbdIEGmP (ORCPT ); Tue, 5 Sep 2017 02:42:15 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:46268 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750704AbdIEGmL (ORCPT ); Tue, 5 Sep 2017 02:42:11 -0400 Subject: Re: [PATCH] swapon: fix vfree() badness To: Dave Chinner , linux-kernel@vger.kernel.org References: <20170905014051.11112-1-david@fromorbit.com> Cc: linux-mm@kvack.org From: Anshuman Khandual Date: Tue, 5 Sep 2017 12:12:02 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170905014051.11112-1-david@fromorbit.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable x-cbid: 17090506-0016-0000-0000-0000026218CB X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17090506-0017-0000-0000-000006E4F4BB Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-09-05_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1709050103 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2525 Lines: 55 On 09/05/2017 07:10 AM, Dave Chinner wrote: > From: Dave Chinner > > The cluster_info structure is allocated with kvzalloc(), which can > return kmalloc'd or vmalloc'd memory. It must be paired with > kvfree(), but sys_swapon uses vfree(), resultin in this warning > from xfstests generic/357: > > [ 1985.294915] swapon: swapfile has holes > [ 1985.296012] Trying to vfree() bad address (ffff88011569ac00) > [ 1985.297769] ------------[ cut here ]------------ > [ 1985.299017] WARNING: CPU: 4 PID: 980 at mm/vmalloc.c:1521 __vunmap+0x97/0xb0 > [ 1985.300868] CPU: 4 PID: 980 Comm: swapon Tainted: G W 4.13.0-dgc #55 > [ 1985.303086] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 > [ 1985.305421] task: ffff88083599c800 task.stack: ffffc90006d68000 > [ 1985.306896] RIP: 0010:__vunmap+0x97/0xb0 > [ 1985.307866] RSP: 0018:ffffc90006d6be68 EFLAGS: 00010296 > [ 1985.309300] RAX: 0000000000000030 RBX: ffff88011569ac00 RCX: 0000000000000000 > [ 1985.311066] RDX: ffff88013fc949d8 RSI: ffff88013fc8cb98 RDI: ffff88013fc8cb98 > [ 1985.312803] RBP: ffffc90006d6be80 R08: 000000000004844c R09: 0000000000001578 > [ 1985.314672] R10: ffffffff82271b20 R11: ffffffff8256e16d R12: 000000000000000a > [ 1985.316444] R13: 0000000000000001 R14: 00000000ffffffea R15: ffff880139a96000 > [ 1985.318230] FS: 00007fb23ac0e880(0000) GS:ffff88013fc80000(0000) knlGS:0000000000000000 > [ 1985.320081] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 1985.321503] CR2: 0000564cdb0c7000 CR3: 0000000137448000 CR4: 00000000000406e0 > [ 1985.323140] Call Trace: > [ 1985.323727] vfree+0x2e/0x70 > [ 1985.324403] SyS_swapon+0x433/0x1080 > [ 1985.325365] entry_SYSCALL_64_fastpath+0x1a/0xa5 > > Fix this as well as the memory leak caused by a missing kvfree(frontswap_map) in > the error handling code. > > cc: > Signed-Off-By: Dave Chinner Reviewed-by: Anshuman Khandual > --- > mm/swapfile.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 6ba4aab2db0b..a8952b6563c6 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -3052,7 +3052,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) > p->flags = 0; > spin_unlock(&swap_lock); > vfree(swap_map); > - vfree(cluster_info); > + kvfree(cluster_info); > + kvfree(frontswap_map); Its correct in swapoff() system call but got missed here.