From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELt4plLPJRnmLWkwp0tJipH9cng/yKZ6s1fWveoU9WDOhm0fnrOhJMOnbnPDtyiE2eJDYoyE ARC-Seal: i=1; a=rsa-sha256; t=1521192101; cv=none; d=google.com; s=arc-20160816; b=mL7k1OvM/yKTgZaKY4RepZLxjmfLY+TKrVsj7J63gHqbCzI9lFCC3wT0b1E/d7ZPen R5kDUIJSWv47y3hKTJxYf2rgXrnOn5zVMY2xvMrcVWchdBEV9rcYRYLJ+VKUWKmseXEv k/pwD2aHGLiA3UX8Arn4FYCFbePWI9zabz9DmQd4QqPiOMAMdx3N9hVKvFfmuFhSltft WH7VSq+VJybmK1oycoj0nWuJjSg2GoKwX7/winwFhxXFtMGD5h7KByZykVSElDbXVNgR HFHZ/KiYkmiqMau/1zjMhHrehhlZd6xlsdFquDrwjwTkpHejoNJXoebvOhg5nMs0VI3o xAaA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:content-language:content-transfer-encoding:in-reply-to :mime-version:user-agent:date:from:references:cc:to:subject :arc-authentication-results; bh=l6ioP42jvsOFvJmlvsLlrdjrZnsFtNJOkW6YKVjVnC4=; b=c+IoMHII3rkqJsTAcT2FoH8zja8pLtChHAZhcUAHTlWcFDnaJo4BwkArYkk3QbTAz4 fA68qpiCMUGL8tvAwZ3ITyGN4N3Hb0TbNxlkpcGQ7Gl4rZZkZK3Gscng0S9Zn9tHgops kNAjvfzBu6SC01baBsrjp8AjPKk+iTW7uRyu04VRdNByYt5V+8ePyHTdlb0LVTjgwj7k JP7MX+jilqKYtlSIGcoMWTsgexVQsmVreQcCbqcrS8D04buYhC1WKKnM9h4H4FqolEnJ 38W2REnm6Q+uNoA5nltTkYGl/EX56N6jqlkWxJGMW7FKBw5jAJn/h8mP8sbEA0rOm3te pZdQ== ARC-Authentication-Results: i=1; mx.google.com; spf=neutral (google.com: 148.163.156.1 is neither permitted nor denied by best guess record for domain of ravi.bangoria@linux.vnet.ibm.com) smtp.mailfrom=ravi.bangoria@linux.vnet.ibm.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Authentication-Results: mx.google.com; spf=neutral (google.com: 148.163.156.1 is neither permitted nor denied by best guess record for domain of ravi.bangoria@linux.vnet.ibm.com) smtp.mailfrom=ravi.bangoria@linux.vnet.ibm.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Subject: Re: [PATCH 5/8] trace_uprobe: Support SDT markers having reference count (semaphore) To: Oleg Nesterov Cc: mhiramat@kernel.org, peterz@infradead.org, srikar@linux.vnet.ibm.com, acme@kernel.org, ananth@linux.vnet.ibm.com, akpm@linux-foundation.org, alexander.shishkin@linux.intel.com, alexis.berlemont@gmail.com, corbet@lwn.net, dan.j.williams@intel.com, gregkh@linuxfoundation.org, huawei.libin@huawei.com, hughd@google.com, jack@suse.cz, jglisse@redhat.com, jolsa@redhat.com, kan.liang@intel.com, kirill.shutemov@linux.intel.com, kjlx@templeofstupid.com, kstewart@linuxfoundation.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, milian.wolff@kdab.com, mingo@redhat.com, namhyung@kernel.org, naveen.n.rao@linux.vnet.ibm.com, pc@us.ibm.com, pombredanne@nexb.com, rostedt@goodmis.org, tglx@linutronix.de, tmricht@linux.vnet.ibm.com, willy@infradead.org, yao.jin@linux.intel.com, fengguang.wu@intel.com, Ravi Bangoria References: <20180313125603.19819-1-ravi.bangoria@linux.vnet.ibm.com> <20180313125603.19819-6-ravi.bangoria@linux.vnet.ibm.com> <20180315142120.GA19218@redhat.com> From: Ravi Bangoria Date: Fri, 16 Mar 2018 14:51:52 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180315142120.GA19218@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18031609-0020-0000-0000-00000405DCA6 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18031609-0021-0000-0000-00004299E842 Message-Id: <56ae982d-2fbf-09c4-989b-57bce5a1cb04@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-16_05:,, 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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1803160114 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594827101403620100?= X-GMAIL-MSGID: =?utf-8?q?1595085529397175942?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 03/15/2018 07:51 PM, Oleg Nesterov wrote: > On 03/13, Ravi Bangoria wrote: >> @@ -1053,6 +1056,9 @@ int uprobe_mmap(struct vm_area_struct *vma) >> struct uprobe *uprobe, *u; >> struct inode *inode; >> >> + if (uprobe_mmap_callback) >> + uprobe_mmap_callback(vma); >> + >> if (no_uprobe_events() || !valid_vma(vma, true)) >> return 0; > probe_event_enable() does > > uprobe_register(); > /* WINDOW */ > sdt_increment_ref_ctr(); > > what if uprobe_mmap() is called in between? The counter(s) in this vma > will be incremented twice, no? I guess, it's a valid issue with PATCH 5 but should be taken care by PATCH 6. > >> +static struct vm_area_struct * >> +sdt_find_vma(struct mm_struct *mm, struct trace_uprobe *tu) >> +{ >> + struct vm_area_struct *tmp; >> + >> + for (tmp = mm->mmap; tmp != NULL; tmp = tmp->vm_next) >> + if (sdt_valid_vma(tu, tmp)) >> + return tmp; >> + >> + return NULL; > I can't understand the logic... Lets ignore sdt_valid_vma() for now. > The caller has uprobe_map_info, why it can't simply do > vma = find_vma(uprobe_map_info->vaddr)? and then check sdt_valid_vma(). Yes. that should work. Will change it. Thanks for the review, Ravi