Add verifier coverage for callback subprograms that declare incoming stack arguments. The test passes a nine-argument callback to bpf_loop() and expects the verifier to reject it.
Assisted-by: Codex:gpt-5 Signed-off-by: Jérémy Jean <[email protected]> --- .../selftests/bpf/progs/verifier_stack_arg.c | 32 +++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c index 7e0ce5db28a0..50b276fc2c3f 100644 --- a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c +++ b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c @@ -27,6 +27,13 @@ static int subprog_7args(int a, int b, int c, int d, int e, int f, int g) return a + b + c + d + e + f + g; } +__noinline __used +static int callback_9args(__u32 index, void *ctx, long a3, long a4, + long a5, long a6, long a7, long a8, long a9) +{ + return a9; +} + __noinline __used static long subprog_deref_arg6(long a, long b, long c, long d, long e, long *f) { @@ -79,6 +86,31 @@ __naked void stack_arg_two_subprogs(void) ); } +SEC("tc") +__description("stack_arg: callback with incoming stack args") +__failure +__naked void stack_arg_callback_many_args(void) +{ + asm volatile ( + "r6 = 0;" + "*(u64 *)(r11 - 32) = 0;" + "*(u64 *)(r11 - 24) = 0;" + "*(u64 *)(r11 - 16) = 0;" + "*(u64 *)(r11 - 8) = 0;" + "r1 = 1;" + "r2 = %[callback_9args];" + "r3 = 0;" + "r4 = 0;" + "call %[bpf_loop];" + "r0 = 0;" + "exit;" + : + : __imm_ptr(callback_9args), + __imm(bpf_loop) + : __clobber_common, "r6" + ); +} + SEC("tc") __description("stack_arg: read from uninitialized stack arg slot") __failure -- 2.47.3
