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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 DD0A5C04EB8 for ; Wed, 5 Dec 2018 03:34:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A87AD20851 for ; Wed, 5 Dec 2018 03:34:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A87AD20851 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726812AbeLEDeR (ORCPT ); Tue, 4 Dec 2018 22:34:17 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42036 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725864AbeLEDeR (ORCPT ); Tue, 4 Dec 2018 22:34:17 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wB53XuNu097447 for ; Tue, 4 Dec 2018 22:34:16 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2p654hupvd-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 04 Dec 2018 22:34:15 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 5 Dec 2018 03:34:07 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wB53Y6Pp50790448 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 5 Dec 2018 03:34:06 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 964CBA405D; Wed, 5 Dec 2018 03:34:06 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 27F1EA4040; Wed, 5 Dec 2018 03:34:03 +0000 (GMT) Received: from bangoria.in.ibm.com (unknown [9.124.31.98]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 5 Dec 2018 03:34:02 +0000 (GMT) From: Ravi Bangoria To: srikar@linux.vnet.ibm.com, oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, liu.song.a23@gmail.com Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, linux-kernel@vger.kernel.org, ananth@linux.vnet.ibm.com, alexis.berlemont@gmail.com, naveen.n.rao@linux.vnet.ibm.com, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux@armlinux.org.uk, ralf@linux-mips.org, paul.burton@mips.com, Ravi Bangoria Subject: [PATCH v2] Uprobes: Fix kernel oops with delayed_uprobe_remove() Date: Wed, 5 Dec 2018 09:04:23 +0530 X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181204005803.787578e7@vmware.local.home> References: <20181204005803.787578e7@vmware.local.home> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18120503-4275-0000-0000-000002EC263F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18120503-4276-0000-0000-000037F93049 Message-Id: <20181205033423.26242-1-ravi.bangoria@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-12-04_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812050031 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There could be a race between task exit and probe unregister: exit_mm() mmput() __mmput() uprobe_unregister() uprobe_clear_state() put_uprobe() delayed_uprobe_remove() delayed_uprobe_remove() put_uprobe() is calling delayed_uprobe_remove() without taking delayed_uprobe_lock and thus the race sometimes results in a kernel crash. Fix this by taking delayed_uprobe_lock before calling delayed_uprobe_remove() from put_uprobe(). Detailed crash log can be found at: https://lkml.org/lkml/2018/11/1/1244 Reported-by: syzbot+cb1fb754b771caca0a88@syzkaller.appspotmail.com Fixes: 1cc33161a83d ("uprobes: Support SDT markers having reference count (semaphore)") Signed-off-by: Ravi Bangoria --- kernel/events/uprobes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 322e97bbb437..abbd8da9ac21 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -572,7 +572,9 @@ static void put_uprobe(struct uprobe *uprobe) * gets called, we don't get a chance to remove uprobe from * delayed_uprobe_list from remove_breakpoint(). Do it here. */ + mutex_lock(&delayed_uprobe_lock); delayed_uprobe_remove(uprobe, NULL); + mutex_unlock(&delayed_uprobe_lock); kfree(uprobe); } } -- 2.19.2