ftrace: fix incorrect hash size in register_ftrace_direct()

[ Upstream commit 92f1d3b40179b15630d72e2c6e4e25a899b67ba9 ]

The maximum of the ftrace hash bits is made fls(32) in
register_ftrace_direct(), which seems illogical. So, we fix it by making
the max hash bits FTRACE_HASH_MAX_BITS instead.

Link: https://lore.kernel.org/20250413014444.36724-1-dongml2@chinatelecom.cn
Fixes: d05cb470663a ("ftrace: Fix modification of direct_function hash while in use")
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 90b59c627bb8e7115847f3a842d3e725931b41ea..e67d67f7b90650bee4dfd455251fe6624048bf4d 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5944,9 +5944,10 @@ int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 
        /* Make a copy hash to place the new and the old entries in */
        size = hash->count + direct_functions->count;
-       if (size > 32)
-               size = 32;
-       new_hash = alloc_ftrace_hash(fls(size));
+       size = fls(size);
+       if (size > FTRACE_HASH_MAX_BITS)
+               size = FTRACE_HASH_MAX_BITS;
+       new_hash = alloc_ftrace_hash(size);
        if (!new_hash)
                goto out_unlock;