From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELtZSwNUclha3HjDrdP2p8d1uPCyrQ71lA6Yxg5GE9gF/gq+4Khv0cd9BhZpca2ugmmNnoTj ARC-Seal: i=1; a=rsa-sha256; t=1521046791; cv=none; d=google.com; s=arc-20160816; b=g+g5hjk2CaLlDBjWYw0UyzhBQbifEK8kgnVNSAptipADkayb64SKd3smhTVJ7X8sdG NEn4E0NcR1XOes4wwN7O9IpFDKRmEG1IQYnfNXs/W/GwiXDIvBeq78q3NAaFOQxLw1eZ 5SGV1NmLLri++LrDaIekKHhLyyj3cA89UCOfEskSl4thuca0OkXYrk3E7JP7EDwtGPWV RuR7tu6vhoNVxMYDTxM1dIL8IE5i0BdDkq1eiKKJaPddYQ23GIMkFsM0RX02EVAfsiPz XyRik1siLWUxZSBhs8SQjv9GqhSZDB6h4Ey+xcZ3kWR4MOzPu5kP0dpQtSYVPtJBNd3p mYlA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:arc-authentication-results; bh=fd7p1NL0ey9DoeCT5PnHLDV/IHyyTrP+nt2/gpIiCjE=; b=r2Cz9n2dHEks7rfacG+3vTJGZecgHe+lfJpAz0JZK+yxxyC+jMHJmO8j6RxfqvuSoX hpU4PPdPF5JKuleVdiVxHFgQe7xpayRpTQTS2aKsCbM5jCmUESohCJ4D0XqQQTdkHR2S MS+zSBGeOZylCRFenivx4GH7QWzRpaXMbehkJfNMCdO069SKJ9eAK4WGiGcPa85yu57R IV9d/htQ/xnHQ5dZgix5GQDF14hdIgASKifMJTAK7Zc1lhQJ0qQSMEikLSzYarnyxM0o 12YKqoZHUgucvh9MVSWAkQzOZmofrDZFmAEXPpXGNh3/KF4kA29bp/NTIfuS7EITYHOC rbOA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of oleg@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=oleg@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of oleg@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=oleg@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Date: Wed, 14 Mar 2018 17:59:44 +0100 From: Oleg Nesterov To: Ravi Bangoria 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 Subject: Re: [PATCH 5/8] trace_uprobe: Support SDT markers having reference count (semaphore) Message-ID: <20180314165943.GA5948@redhat.com> References: <20180313125603.19819-1-ravi.bangoria@linux.vnet.ibm.com> <20180313125603.19819-6-ravi.bangoria@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180313125603.19819-6-ravi.bangoria@linux.vnet.ibm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594827101403620100?= X-GMAIL-MSGID: =?utf-8?q?1594933160270065515?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 03/13, Ravi Bangoria wrote: > > +static bool sdt_valid_vma(struct trace_uprobe *tu, struct vm_area_struct *vma) > +{ > + unsigned long vaddr = vma_offset_to_vaddr(vma, tu->ref_ctr_offset); > + > + return tu->ref_ctr_offset && > + vma->vm_file && > + file_inode(vma->vm_file) == tu->inode && > + vma->vm_flags & VM_WRITE && > + vma->vm_start <= vaddr && > + vma->vm_end > vaddr; > +} Perhaps in this case a simple ref_ctr_offset < vma->vm_end - vma->vm_start check without vma_offset_to_vaddr() makes more sense, but I won't insist. > +static void sdt_increment_ref_ctr(struct trace_uprobe *tu) > +{ > + struct uprobe_map_info *info; > + struct vm_area_struct *vma; > + unsigned long vaddr; > + > + uprobe_start_dup_mmap(); > + info = uprobe_build_map_info(tu->inode->i_mapping, > + tu->ref_ctr_offset, false); Hmm. This doesn't look right. If you need to find all mappings (and avoid the races with fork/dup_mmap) you need to take this semaphore for writing, uprobe_start_dup_mmap() can't help. Oleg.