bpf: Use GFP_KERNEL in bpf_event_entry_gen()

rcu_read_lock() is no longer held when invoking bpf_event_entry_gen()
which is called by perf_event_fd_array_get_ptr(), so using GFP_KERNEL
instead of GFP_ATOMIC to reduce the possibility of failures due to
out-of-memory.

Acked-by: Yonghong Song <[email protected]>
Signed-off-by: Hou Tao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: Hou Tao

kernel/bpf/arraymap.c

@@ -1195,7 +1195,7 @@ static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
 {
 	struct bpf_event_entry *ee;
 
-	ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
+	ee = kzalloc(sizeof(*ee), GFP_KERNEL);
 	if (ee) {
 		ee->event = perf_file->private_data;
 		ee->perf_file = perf_file;