From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966778AbcKLSCY (ORCPT ); Sat, 12 Nov 2016 13:02:24 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:34512 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966525AbcKLSCW (ORCPT ); Sat, 12 Nov 2016 13:02:22 -0500 Date: Sat, 12 Nov 2016 10:02:18 -0800 From: "Paul E. McKenney" To: Yang Shi Cc: josh@joshtriplett.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org Subject: Re: [PATCH] locktorture: Fix potential memory leak with rw lock test Reply-To: paulmck@linux.vnet.ibm.com References: <1478811999-12696-1-git-send-email-yang.shi@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1478811999-12696-1-git-send-email-yang.shi@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16111218-8235-0000-0000-0000099A8170 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006065; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000189; SDB=6.00779911; UDB=6.00375910; IPR=6.00557297; BA=6.00004873; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00013305; XFM=3.00000011; UTC=2016-11-12 18:02:20 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16111218-8236-0000-0000-0000366ABC98 Message-Id: <20161112180218.GW4127@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-11-12_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1611120327 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 10, 2016 at 01:06:39PM -0800, Yang Shi wrote: > When running locktorture module with the below commands with kmemleak enabled: > > $ modprobe locktorture torture_type=rw_lock_irq > $ rmmod locktorture > > The below kmemleak got caught: > > root@10:~# echo scan > /sys/kernel/debug/kmemleak > [ 323.197029] kmemleak: 2 new suspected memory leaks (see /sys/kernel/debug/kmemleak) > root@10:~# cat /sys/kernel/debug/kmemleak > unreferenced object 0xffffffc07592d500 (size 128): > comm "modprobe", pid 368, jiffies 4294924118 (age 205.824s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 c3 7b 02 00 00 00 00 00 .........{...... > 00 00 00 00 00 00 00 00 d7 9b 02 00 00 00 00 00 ................ > backtrace: > [] create_object+0x110/0x288 > [] kmemleak_alloc+0x58/0xa0 > [] __kmalloc+0x234/0x318 > [] 0xffffff80006fa130 > [] do_one_initcall+0x44/0x138 > [] do_init_module+0x68/0x1cc > [] load_module+0x1a68/0x22e0 > [] SyS_finit_module+0xe0/0xf0 > [] el0_svc_naked+0x24/0x28 > [] 0xffffffffffffffff > unreferenced object 0xffffffc07592d480 (size 128): > comm "modprobe", pid 368, jiffies 4294924118 (age 205.824s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 3b 6f 01 00 00 00 00 00 ........;o...... > 00 00 00 00 00 00 00 00 23 6a 01 00 00 00 00 00 ........#j...... > backtrace: > [] create_object+0x110/0x288 > [] kmemleak_alloc+0x58/0xa0 > [] __kmalloc+0x234/0x318 > [] 0xffffff80006fa22c > [] do_one_initcall+0x44/0x138 > [] do_init_module+0x68/0x1cc > [] load_module+0x1a68/0x22e0 > [] SyS_finit_module+0xe0/0xf0 > [] el0_svc_naked+0x24/0x28 > [] 0xffffffffffffffff > > It is because cxt.lwsa and cxt.lrsa don't get freed in module_exit, so free > them in lock_torture_cleanup() and free writer_tasks if reader_tasks is > failed at memory allocation. > > Signed-off-by: Yang Shi Good catch! Queued for review and testing. Thanx, Paul > --- > kernel/locking/locktorture.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c > index f8c5af5..d3de04b 100644 > --- a/kernel/locking/locktorture.c > +++ b/kernel/locking/locktorture.c > @@ -780,6 +780,10 @@ static void lock_torture_cleanup(void) > else > lock_torture_print_module_parms(cxt.cur_ops, > "End of test: SUCCESS"); > + > + kfree(cxt.lwsa); > + kfree(cxt.lrsa); > + > end: > torture_cleanup_end(); > } > @@ -924,6 +928,8 @@ static int __init lock_torture_init(void) > GFP_KERNEL); > if (reader_tasks == NULL) { > VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory"); > + kfree(writer_tasks); > + writer_tasks = NULL; > firsterr = -ENOMEM; > goto unwind; > } > -- > 2.0.2 >