From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754592Ab3G3Lb5 (ORCPT ); Tue, 30 Jul 2013 07:31:57 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:9362 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751649Ab3G3Lby (ORCPT ); Tue, 30 Jul 2013 07:31:54 -0400 X-Authority-Analysis: v=2.0 cv=aqMw+FlV c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=d_O34BjmFfwA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=YYX2g-drga8A:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=3nbZYyFuAAAA:8 a=y4oymp9fq9aDtU_duecA:9 a=jEp0ucaQiEUA:10 a=EvKJbDF4Ut8A:10 a=jeBq3FmKZ4MA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130730113152.135431410@goodmis.org> User-Agent: quilt/0.60-1 Date: Tue, 30 Jul 2013 07:27:19 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Frederic Weisbecker , Andrew Morton , Masami Hiramatsu , Oleg Nesterov Subject: [for-next-3.11][PATCH 1/8] tracing: Turn event/id->i_private into call->event.type References: <20130730112718.273490378@goodmis.org> Content-Disposition: inline; filename=0001-tracing-Turn-event-id-i_private-into-call-event.type.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oleg Nesterov event_id_read() is racy, ftrace_event_call can be already freed by trace_remove_event_call() callers. Change event_create_dir() to pass "data = call->event.type", this is all event_id_read() needs. ftrace_event_id_fops no longer needs tracing_open_generic(). We add the new helper, event_file_data(), to read ->i_private, it will have more users. Note: currently ACCESS_ONCE() and "id != 0" check are not needed, but we are going to change event_remove/rmdir to clear ->i_private. Link: http://lkml.kernel.org/r/20130726172532.GA3605@redhat.com Reviewed-by: Masami Hiramatsu Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 898f868..c2d13c5 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -409,6 +409,11 @@ static void put_system(struct ftrace_subsystem_dir *dir) mutex_unlock(&event_mutex); } +static void *event_file_data(struct file *filp) +{ + return ACCESS_ONCE(file_inode(filp)->i_private); +} + /* * Open and update trace_array ref count. * Must have the current trace_array passed to it. @@ -946,14 +951,18 @@ static int trace_format_open(struct inode *inode, struct file *file) static ssize_t event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - struct ftrace_event_call *call = filp->private_data; + int id = (long)event_file_data(filp); char buf[32]; int len; if (*ppos) return 0; - len = sprintf(buf, "%d\n", call->event.type); + if (unlikely(!id)) + return -ENODEV; + + len = sprintf(buf, "%d\n", id); + return simple_read_from_buffer(ubuf, cnt, ppos, buf, len); } @@ -1240,7 +1249,6 @@ static const struct file_operations ftrace_event_format_fops = { }; static const struct file_operations ftrace_event_id_fops = { - .open = tracing_open_generic, .read = event_id_read, .llseek = default_llseek, }; @@ -1488,8 +1496,8 @@ event_create_dir(struct dentry *parent, #ifdef CONFIG_PERF_EVENTS if (call->event.type && call->class->reg) - trace_create_file("id", 0444, file->dir, call, - id); + trace_create_file("id", 0444, file->dir, + (void *)(long)call->event.type, id); #endif /* -- 1.7.10.4