bpf: Avoid warning on unexpected map for tail call

Before handling the tail call in record_func_key(), we check that the
map is of the expected type and log a verifier error if it isn't. Such
an error however doesn't indicate anything wrong with the verifier. The
check for map<>func compatibility is done after record_func_key(), by
check_map_func_compatibility().

Therefore, this patch logs the error as a typical reject instead of a
verifier error.

Fixes: d2e4c1e6c294 ("bpf: Constant map key tracking for prog array pokes")
Fixes: 0df1a55afa83 ("bpf: Warn on internal verifier errors")
Reported-by: syzbot+efb099d5833bca355e51@syzkaller.appspotmail.com
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/1f395b74e73022e47e04a31735f258babf305420.1751578055.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9f09dcd2eabbba43d2e9b42c44c306d9eadb31d4..29e0dddc22f836187c6cda5dc491d82373eca8a9 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11082,8 +11082,8 @@ record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
        if (func_id != BPF_FUNC_tail_call)
                return 0;
        if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
-               verifier_bug(env, "expected array map for tail call");
-               return -EFAULT;
+               verbose(env, "expected prog array map for tail call");
+               return -EINVAL;
        }
 
        reg = &regs[BPF_REG_3];