Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751424AbdIMGH6 (ORCPT ); Wed, 13 Sep 2017 02:07:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:45326 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751056AbdIMGHz (ORCPT ); Wed, 13 Sep 2017 02:07:55 -0400 Date: Wed, 13 Sep 2017 08:07:52 +0200 From: Michal Hocko To: Dave Chinner Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton Subject: Re: [PATCH] swapon: fix vfree() badness Message-ID: <20170913060752.6jfmvs7ruipzb6gs@dhcp22.suse.cz> References: <20170905014051.11112-1-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170905014051.11112-1-david@fromorbit.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3008 Lines: 73 On Tue 05-09-17 11:40:51, 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. Yes the patch is correct. Darrick has posted a similar fix http://lkml.kernel.org/r/20170831233515.GR3775@magnolia and it is sitting in the Andrew's tree already (with the follow up from David to address frontswap_map) Thanks! > > cc: > Signed-Off-By: Dave Chinner > --- > 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); > if (swap_file) { > if (inode && S_ISREG(inode->i_mode)) { > inode_unlock(inode); > -- > 2.13.3 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- Michal Hocko SUSE Labs