[PATCH 1/3] ftrace: Use direct_ops hash in unregister_ftrace_direct

Jiri Olsa
2021-12-05T23:20:51Z

Now when we have *direct_multi interface the direct_functions
hash is no longer owned just by direct_ops. It's also used by
any other ftrace_ops passed to *direct_multi interface.

Thus to find out that we are unregistering the last function
from direct_ops, we need to check directly direct_ops's hash.

Fixes: f64dd4627ec6 ("ftrace: Add multi direct register/unregister interface")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/trace/ftrace.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 30bc880c3849..7f0594e28226 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5217,6 +5217,7 @@ int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
{
struct ftrace_direct_func *direct;
struct ftrace_func_entry *entry;
+ struct ftrace_hash *hash;
int ret = -ENODEV;

mutex_lock(&direct_mutex);
@@ -5225,7 +5226,8 @@ int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
if (!entry)
goto out_unlock;

- if (direct_functions->count == 1)
+ hash = direct_ops.func_hash->filter_hash;
+ if (hash->count == 1)
unregister_ftrace_function(&direct_ops);

ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
--
2.33.1