[for-linus][PATCH 4/6] fprobe: Check rethook_alloc() return in rethook initialization

[Steven Rostedt <rostedt@goodmis.org>]

From: Rafael Mendonca <rafaelmendsr@gmail.com>

Check if fp->rethook succeeded to be allocated. Otherwise, if
rethook_alloc() fails, then we end up dereferencing a NULL pointer in
rethook_add_node().

Link: https://lore.kernel.org/all/20221025031209.954836-1-rafaelmendsr@gmail.com/

Fixes: 5b0ab78998e3 ("fprobe: Add exit_handler support")
Cc: stable@vger.kernel.org
Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 kernel/trace/fprobe.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index aac63ca9c3d1..71614b2a67ff 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -141,6 +141,8 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
 		return -E2BIG;
 
 	fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler);
+	if (!fp->rethook)
+		return -ENOMEM;
 	for (i = 0; i < size; i++) {
 		struct fprobe_rethook_node *node;
 
-- 
2.35.1