[PATCH] ftrace/direct: Fix lockup in modify_ftrace_direct_multi

From: Jiri Olsa
Date: Tue Nov 09 2021 - 06:42:33 EST


We can't call unregister_ftrace_function under ftrace_lock.

Fixes: ed29271894aa ("ftrace/direct: Do not disable when switching direct callers")
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
kernel/trace/ftrace.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b4ed1a301232..fc49e8809a56 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5602,10 +5602,11 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
}
}

+ mutex_unlock(&ftrace_lock);
+
/* Removing the tmp_ops will add the updated direct callers to the functions */
unregister_ftrace_function(&tmp_ops);

- mutex_unlock(&ftrace_lock);
out_direct:
mutex_unlock(&direct_mutex);
return err;
--
2.32.0