From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELs/AwTfHVBD8C8v4QU8vxiZQSpZRE01Eh7wcuf6A+7u+vmFCT5yr5TdP+Nm8xxB/Yyfp6L0 ARC-Seal: i=1; a=rsa-sha256; t=1521192410; cv=none; d=google.com; s=arc-20160816; b=Rl1nvMatIgte5Zhhne34YoA2DczflGxeNHWpi7ESJCL4vxXRnjZDPHqeJ8bUJKocZX 3z4QPQniY2AaOkBjS5n0pYtIdlRglaNC6zvwZE6Wj4H0RFrmll1czqejSHBwwSyI6W3K Yz/A8z8dJI/ApcAdMQD61x/zuQBgXV+mC/JJkhEupIPXyM3M6IfXUMoaOikosNn7GOJl di3vSfMpvobpQWproFviHHHxnGBalb/mc8wTEcxTwIvXOVV5xc8h02pog1ie8IfwJ0Jd kyWB00twziIsWXBj/tna0CZP7GirWmRtjVKA3uHX/kKyngwpmoWSdtFq3yc+yslt25TL AJxw== 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:references:cc:to:subject:from :arc-authentication-results; bh=P8XPhFrG1W2aZYHic2nMCIc//ASp6LBjgFyR6AFFHxo=; b=IHFP28TsKccGHmtY2KtJIwifzoo7T2gBWbuxF1VvkfIrpylme/6VMPeWGLKRQ1EyzG KdO9mi5M+W5K0uukpafciNcRInPHQ87b+v2Lt9Kz+ZyicFfo+qbgdrmRa7CGa1DnEcAw vbvSvJgPcflE5moydq08VvcMhAcqynh/Tqm+/phsvnqCMzYwbxJWPlstMc+4yslNGQqk JJBMuXWQ2PwAtsVgFIzyvj5hHamTFIQIL6nvVJvR5Z3NAmNhZ7dtK2bCdsT4k8Zi6ejn ZiAuGOjr4tM/P/0piSOYD6IjaOdGyCEllOSP8vylp+g/IBVFDqAfsR9QJ+6h7FjPcUAV RPkw== ARC-Authentication-Results: i=1; mx.google.com; spf=neutral (google.com: 148.163.158.5 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: 148.163.158.5 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 From: Ravi Bangoria 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> <20180315143044.GA19643@redhat.com> Date: Fri, 16 Mar 2018 14:58:55 +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: <20180315143044.GA19643@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18031609-0012-0000-0000-000005BFD826 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18031609-0013-0000-0000-0000193BE594 Message-Id: <3b303a2d-35dd-9178-fc03-de9f2d588797@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-1803160115 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594827101403620100?= X-GMAIL-MSGID: =?utf-8?q?1595085852832024515?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 03/15/2018 08:00 PM, Oleg Nesterov wrote: > On 03/15, Oleg Nesterov wrote: >>> +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(). > Note to mention that sdt_find_vma() can return NULL but the callers do > vma_offset_to_vaddr(vma) without any check. If the "mm" we are passing to sdt_find_vma() is returned by uprobe_build_map_info(ref_ctr_offset), sdt_find_vma() must _not_ return NULL. Thanks for the review, Ravi