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tracing: Increase trace array ref count on enable and filter files

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[ Upstream commit f5ca233e2e66dc1c249bf07eefa37e34a6c9346a ]

When the trace event enable and filter files are opened, increment the
trace array ref counter, otherwise they can be accessed when the trace
array is being deleted. The ref counter keeps the trace array from being
deleted while those files are opened.

Link: https://lkml.kernel.org/r/20230907024803.456187066@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>
Fixes: 8530dec63e ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Steven Rostedt (Google) 2023-09-06 22:47:12 -04:00 committed by Greg Kroah-Hartman
parent 7d3f6612e9
commit e6807c873d
3 changed files with 33 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
kernel/trace/trace.c
View File

@ -4244,6 +4244,33 @@ int tracing_open_generic_tr(struct inode *inode, struct file *filp)
return 0;
}
/*
* The private pointer of the inode is the trace_event_file.
* Update the tr ref count associated to it.
*/
int tracing_open_file_tr(struct inode *inode, struct file *filp)
{
struct trace_event_file *file = inode->i_private;
int ret;
ret = tracing_check_open_get_tr(file->tr);
if (ret)
return ret;
filp->private_data = inode->i_private;
return 0;
}
int tracing_release_file_tr(struct inode *inode, struct file *filp)
{
struct trace_event_file *file = inode->i_private;
trace_array_put(file->tr);
return 0;
}
static int tracing_release(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;

2
kernel/trace/trace.h
View File

@ -680,6 +680,8 @@ void tracing_reset_all_online_cpus(void);
void tracing_reset_all_online_cpus_unlocked(void);
int tracing_open_generic(struct inode *inode, struct file *filp);
int tracing_open_generic_tr(struct inode *inode, struct file *filp);
int tracing_open_file_tr(struct inode *inode, struct file *filp);
int tracing_release_file_tr(struct inode *inode, struct file *filp);
bool tracing_is_disabled(void);
bool tracer_tracing_is_on(struct trace_array *tr);
void tracer_tracing_on(struct trace_array *tr);

6
kernel/trace/trace_events.c
View File

@ -1699,9 +1699,10 @@ static const struct file_operations ftrace_set_event_pid_fops = {
};
static const struct file_operations ftrace_enable_fops = {
.open = tracing_open_generic,
.open = tracing_open_file_tr,
.read = event_enable_read,
.write = event_enable_write,
.release = tracing_release_file_tr,
.llseek = default_llseek,
};
@ -1718,9 +1719,10 @@ static const struct file_operations ftrace_event_id_fops = {
};
static const struct file_operations ftrace_event_filter_fops = {
.open = tracing_open_generic,
.open = tracing_open_file_tr,
.read = event_filter_read,
.write = event_filter_write,
.release = tracing_release_file_tr,
.llseek = default_llseek,
};