From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752709AbaFEOj6 (ORCPT ); Thu, 5 Jun 2014 10:39:58 -0400 Received: from terminus.zytor.com ([198.137.202.10]:48685 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751898AbaFEOj4 (ORCPT ); Thu, 5 Jun 2014 10:39:56 -0400 Date: Thu, 5 Jun 2014 07:38:57 -0700 From: tip-bot for Oleg Nesterov Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, acme@kernel.org, hughd@google.com, dvlasenk@redhat.com, srikar@linux.vnet.ibm.com, tglx@linutronix.de, oleg@redhat.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, hughd@google.com, acme@kernel.org, srikar@linux.vnet.ibm.com, dvlasenk@redhat.com, oleg@redhat.com, tglx@linutronix.de In-Reply-To: <20140519184054.GA6750@redhat.com> References: <20140519184054.GA6750@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] uprobes: Shift ->readpage check from __copy_insn( ) to uprobe_register() Git-Commit-ID: 41ccba029e9492dd0fc1bf5c23b72c6322a6dfe9 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 41ccba029e9492dd0fc1bf5c23b72c6322a6dfe9 Gitweb: http://git.kernel.org/tip/41ccba029e9492dd0fc1bf5c23b72c6322a6dfe9 Author: Oleg Nesterov AuthorDate: Mon, 19 May 2014 20:40:54 +0200 Committer: Ingo Molnar CommitDate: Thu, 5 Jun 2014 12:30:07 +0200 uprobes: Shift ->readpage check from __copy_insn() to uprobe_register() copy_insn() fails with -EIO if ->readpage == NULL, but this error is not propagated unless uprobe_register() path finds ->mm which already mmaps this file. In this case (say) "perf record" does not actually install the probe, but the user can't know about this. Move this check into uprobe_register() so that this problem can be detected earlier and reported to user. Note: this is still not perfect, - copy_insn() and arch_uprobe_analyze_insn() should be called by uprobe_register() but this is not simple, we need vm_file for read_mapping_page() (although perhaps we can pass NULL), and we need ->mm for is_64bit_mm() (although this logic is broken anyway). - uprobe_register() should be called by create_trace_uprobe(), not by probe_event_enable(), so that an error can be detected at "perf probe -x" time. This also needs more changes in the core uprobe code, uprobe register/unregister interface was poorly designed from the very beginning. Reported-by: Denys Vlasenko Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Signed-off-by: Peter Zijlstra Cc: Hugh Dickins Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20140519184054.GA6750@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 3b02c72..c56b13e 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -536,9 +536,6 @@ static int __copy_insn(struct address_space *mapping, struct file *filp, void *insn, int nbytes, loff_t offset) { struct page *page; - - if (!mapping->a_ops->readpage) - return -EIO; /* * Ensure that the page that has the original instruction is * populated and in page-cache. @@ -879,6 +876,9 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * if (!uc->handler && !uc->ret_handler) return -EINVAL; + /* copy_insn()->read_mapping_page() needs ->readpage() */ + if (!inode->i_mapping->a_ops->readpage) + return -EIO; /* Racy, just to catch the obvious mistakes */ if (offset > i_size_read(inode)) return -EINVAL;