From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Oleg Nesterov <oleg@redhat.com>
Subject: [for-next-3.11][PATCH 2/8] tracing: Change event_enable/disable_read() to verify i_private != NULL
Date: Tue, 30 Jul 2013 07:27:20 -0400 [thread overview]
Message-ID: <20130730113152.279015307@goodmis.org> (raw)
In-Reply-To: 20130730112718.273490378@goodmis.org
[-- Attachment #1: 0002-tracing-Change-event_enable-disable_read-to-verify-i.patch --]
[-- Type: text/plain, Size: 2546 bytes --]
From: Oleg Nesterov <oleg@redhat.com>
tracing_open_generic_file() is racy, ftrace_event_file can be
already freed by rmdir or trace_remove_event_call().
Change event_enable_read() and event_disable_read() to read and
verify "file = i_private" under event_mutex.
This fixes nothing, but now we can change debugfs_remove("enable")
callers to nullify ->i_private and fix the the problem.
Link: http://lkml.kernel.org/r/20130726172536.GA3612@redhat.com
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_events.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index c2d13c5..3dfa841 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -684,15 +684,25 @@ static ssize_t
event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
- struct ftrace_event_file *file = filp->private_data;
+ struct ftrace_event_file *file;
+ unsigned long flags;
char buf[4] = "0";
- if (file->flags & FTRACE_EVENT_FL_ENABLED &&
- !(file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
+ mutex_lock(&event_mutex);
+ file = event_file_data(filp);
+ if (likely(file))
+ flags = file->flags;
+ mutex_unlock(&event_mutex);
+
+ if (!file)
+ return -ENODEV;
+
+ if (flags & FTRACE_EVENT_FL_ENABLED &&
+ !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
strcpy(buf, "1");
- if (file->flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
- file->flags & FTRACE_EVENT_FL_SOFT_MODE)
+ if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
+ flags & FTRACE_EVENT_FL_SOFT_MODE)
strcat(buf, "*");
strcat(buf, "\n");
@@ -704,13 +714,10 @@ static ssize_t
event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
- struct ftrace_event_file *file = filp->private_data;
+ struct ftrace_event_file *file;
unsigned long val;
int ret;
- if (!file)
- return -EINVAL;
-
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
@@ -722,8 +729,11 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
switch (val) {
case 0:
case 1:
+ ret = -ENODEV;
mutex_lock(&event_mutex);
- ret = ftrace_event_enable_disable(file, val);
+ file = event_file_data(filp);
+ if (likely(file))
+ ret = ftrace_event_enable_disable(file, val);
mutex_unlock(&event_mutex);
break;
--
1.7.10.4
next prev parent reply other threads:[~2013-07-30 11:33 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-30 11:27 [for-next-3.11][PATCH 0/8] ftrace/tracing: Event file fixes and ftrace function hash fixes Steven Rostedt
2013-07-30 11:27 ` [for-next-3.11][PATCH 1/8] tracing: Turn event/id->i_private into call->event.type Steven Rostedt
2013-07-30 11:27 ` Steven Rostedt [this message]
2013-07-30 11:27 ` [for-next-3.11][PATCH 3/8] tracing: Change event_filter_read/write to verify i_private != NULL Steven Rostedt
2013-07-30 11:27 ` [for-next-3.11][PATCH 4/8] tracing: Change f_start() to take event_mutex and " Steven Rostedt
2013-07-30 11:27 ` [for-next-3.11][PATCH 5/8] tracing: Introduce remove_event_file_dir() Steven Rostedt
2013-07-30 11:27 ` [for-next-3.11][PATCH 6/8] tracing: Change remove_event_file_dir() to clear "d_subdirs"->i_private Steven Rostedt
2013-07-30 11:27 ` [for-next-3.11][PATCH 7/8] ftrace: Consolidate some duplicate code for updating ftrace ops Steven Rostedt
2013-07-30 11:27 ` [for-next-3.11][PATCH 8/8] ftrace: Clear module traced functions on unload module Steven Rostedt
2013-07-30 17:39 ` Steven Rostedt
2013-07-31 11:47 ` [for-next-3.11][PATCH 0/8] ftrace/tracing: Event file fixes and ftrace function hash fixes Oleg Nesterov
2013-07-31 14:06 ` Steven Rostedt
2013-07-31 14:22 ` Oleg Nesterov
2013-07-31 14:29 ` Oleg Nesterov
2013-07-31 16:43 ` Steven Rostedt
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