This is a note to let you know that I've just added the patch titled
tracing: Turn event/id->i_private into call->event.type
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-turn-event-id-i_private-into-call-event.type.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1a11126bcb7c93c289bf3218fa546fd3b0c0df8b Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Date: Fri, 26 Jul 2013 19:25:32 +0200
Subject: tracing: Turn event/id->i_private into call->event.type
From: Oleg Nesterov <oleg@xxxxxxxxxx>
commit 1a11126bcb7c93c289bf3218fa546fd3b0c0df8b upstream.
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@xxxxxxxxxx
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace_events.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -407,6 +407,11 @@ static void put_system(struct ftrace_sub
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.
@@ -960,19 +965,22 @@ static int trace_format_open(struct inod
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);
struct trace_seq *s;
int r;
if (*ppos)
return 0;
+ if (unlikely(!id))
+ return -ENODEV;
+
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
- trace_seq_printf(s, "%d\n", call->event.type);
+ trace_seq_printf(s, "%d\n", id);
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, s->len);
@@ -1263,7 +1271,6 @@ static const struct file_operations ftra
};
static const struct file_operations ftrace_event_id_fops = {
- .open = tracing_open_generic,
.read = event_id_read,
.llseek = default_llseek,
};
@@ -1511,8 +1518,8 @@ 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
/*
Patches currently in stable-queue which might be from oleg@xxxxxxxxxx are
queue-3.10/tracing-introduce-trace_create_cpu_file-and.patch
queue-3.10/tracing-change-tracing_fops-snapshot_fops-to-rely-on-tracing_get_cpu.patch
queue-3.10/tracing-change-tracing_buffers_fops-to-rely-on-tracing_get_cpu.patch
queue-3.10/tracing-change-tracing_stats_fops-to-rely-on.patch
queue-3.10/tracing-change-tracing_pipe_fops-to-rely-on-tracing_get_cpu.patch
queue-3.10/tracing-change-tracing_entries_fops-to-rely-on-tracing_get_cpu.patch
queue-3.10/tracing-turn-event-id-i_private-into-call-event.type.patch
--
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