Commit 7d660c9b authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

tracing: Have tracing_max_latency inc the trace array ref count 

The tracing_max_latency file points to the trace_array max_latency field.
For an instance, if the file is opened and the instance is deleted,
reading or writing to the file will cause a use after free.

Up the ref count of the trace_array when tracing_max_latency is opened.

Link: https://lkml.kernel.org/r/20230907024803.666889383@goodmis.org
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/



Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Fixes: 8530dec6 ("tracing: Add tracing_check_open_get_tr()")
Tested-by: default avatarLinux Kernel Functional Testing <lkft@linaro.org>
Tested-by: default avatarNaresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent f5ca233e

kernel/trace/trace.c

+10 −5
Original line number Diff line number Diff line
@@ -1772,7 +1772,7 @@ static void trace_create_maxlat_file(struct trace_array *tr, 
	init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);

	tr->d_max_latency = trace_create_file("tracing_max_latency",

					      TRACE_MODE_WRITE,

					      d_tracer, &tr->max_latency,

					      d_tracer, tr,

					      &tracing_max_lat_fops);

}
@@ -1805,7 +1805,7 @@ void latency_fsnotify(struct trace_array *tr) 


#define trace_create_maxlat_file(tr, d_tracer)				\

	trace_create_file("tracing_max_latency", TRACE_MODE_WRITE,	\

			  d_tracer, &tr->max_latency, &tracing_max_lat_fops)

			  d_tracer, tr, &tracing_max_lat_fops)



#endif
@@ -6717,14 +6717,18 @@ static ssize_t 
tracing_max_lat_read(struct file *filp, char __user *ubuf,

		     size_t cnt, loff_t *ppos)

{

	return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);

	struct trace_array *tr = filp->private_data;



	return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);

}



static ssize_t

tracing_max_lat_write(struct file *filp, const char __user *ubuf,

		      size_t cnt, loff_t *ppos)

{

	return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);

	struct trace_array *tr = filp->private_data;



	return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);

}



#endif
@@ -7778,10 +7782,11 @@ static const struct file_operations tracing_thresh_fops = { 


#ifdef CONFIG_TRACER_MAX_TRACE

static const struct file_operations tracing_max_lat_fops = {

	.open		= tracing_open_generic,

	.open		= tracing_open_generic_tr,

	.read		= tracing_max_lat_read,

	.write		= tracing_max_lat_write,

	.llseek		= generic_file_llseek,

	.release	= tracing_release_generic_tr,

};

#endif