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authorSteven Rostedt (Google) <rostedt@goodmis.org>2023-09-06 22:47:12 -0400
committerSteven Rostedt (Google) <rostedt@goodmis.org>2023-09-07 16:05:46 -0400
commitf5ca233e2e66dc1c249bf07eefa37e34a6c9346a (patch)
tree7251c2295d3984e3df873c89e0f5ba06f2fdaf78
parent9879e5e1c528d1ee9c4473b1d0668ba988bfb6ca (diff)
tracing: Increase trace array ref count on enable and filter files
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: 8530dec63e7b4 ("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>
-rw-r--r--kernel/trace/trace.c27
-rw-r--r--kernel/trace/trace.h2
-rw-r--r--kernel/trace/trace_events.c6
3 files changed, 33 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 35783a7baf15..0827037ee3b8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4973,6 +4973,33 @@ 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_mark_open(struct inode *inode, struct file *filp)
{
stream_open(inode, filp);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 5669dd1f90d9..77debe53f07c 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -610,6 +610,8 @@ 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);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ed367d713be0..2af92177b765 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2103,9 +2103,10 @@ static const struct file_operations ftrace_set_event_notrace_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,
};
@@ -2122,9 +2123,10 @@ 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,
};