From: "Steven Rostedt (Red Hat)" <rost...@goodmis.org>
Since the RCU unsafe functions are no longer displayed by the
available_filter_functions, we still need a way to see these
functions in order to trace them. Create a new file that lists
the functions that were declared RCU unsafe.
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
include/linux/ftrace.h | 1 +
kernel/trace/ftrace.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 32 insertions(+)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 4709264..4752764 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -412,6 +412,7 @@ enum {
FTRACE_ITER_HASH = (1 << 4),
FTRACE_ITER_ENABLED = (1 << 5),
FTRACE_ITER_NO_UNSAFE = (1 << 6),
+ FTRACE_ITER_UNSAFE_ONLY = (1 << 7),
};
void arch_ftrace_update_code(int command);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index be87ac9..a3e4b71 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2647,6 +2647,9 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
((iter->flags & FTRACE_ITER_ENABLED) &&
!(rec->flags & FTRACE_FL_ENABLED)) ||
+ ((iter->flags & FTRACE_ITER_UNSAFE_ONLY) &&
+ !ftrace_lookup_ip(ftrace_unsafe_rcu, rec->ip)) ||
+
((iter->flags & FTRACE_ITER_NO_UNSAFE) &&
ftrace_lookup_ip(ftrace_unsafe_rcu, rec->ip))) {
@@ -2784,6 +2787,24 @@ ftrace_avail_open(struct inode *inode, struct file *file)
}
static int
+ftrace_rcu_unsafe_open(struct inode *inode, struct file *file)
+{
+ struct ftrace_iterator *iter;
+
+ if (unlikely(ftrace_disabled))
+ return -ENODEV;
+
+ iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
+ if (iter) {
+ iter->pg = ftrace_pages_start;
+ iter->flags = FTRACE_ITER_UNSAFE_ONLY;
+ iter->ops = &global_ops;
+ }
+
+ return iter ? 0 : -ENOMEM;
+}
+
+static int
ftrace_enabled_open(struct inode *inode, struct file *file)
{
struct ftrace_iterator *iter;
@@ -3835,6 +3856,13 @@ static const struct file_operations ftrace_avail_fops = {
.release = seq_release_private,
};
+static const struct file_operations ftrace_rcu_unsafe_fops = {
+ .open = ftrace_rcu_unsafe_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release_private,
+};
+
static const struct file_operations ftrace_enabled_fops = {
.open = ftrace_enabled_open,
.read = seq_read,
@@ -4071,6 +4099,9 @@ static __init int ftrace_init_dyn_debugfs(struct dentry
*d_tracer)
trace_create_file("available_filter_functions", 0444,
d_tracer, NULL, &ftrace_avail_fops);
+ trace_create_file("rcu_unsafe_filter_functions", 0444,
+ d_tracer, NULL, &ftrace_rcu_unsafe_fops);
+
trace_create_file("enabled_functions", 0444,
d_tracer, NULL, &ftrace_enabled_fops);
--
1.7.10.4
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