Add a verifier test with one atomic RMW instruction reached through PTR_TO_ARENA and PTR_TO_STACK paths. The verifier must reject the shared instruction with the existing incompatible-pointer diagnostic.
Signed-off-by: Yiyang Chen <[email protected]> --- tools/testing/selftests/bpf/progs/verifier_arena.c | 39 ++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_arena.c b/tools/testing/selftests/bpf/progs/verifier_arena.c index b241bbcf54a8a..b22bab33301ab 100644 --- a/tools/testing/selftests/bpf/progs/verifier_arena.c +++ b/tools/testing/selftests/bpf/progs/verifier_arena.c @@ -637,6 +637,45 @@ int non_arena_ptr_add_to_arena_ptr(void *ctx) #endif +static const struct bpf_insn addr_space_cast_insn = { + .code = 0xbf, + .dst_reg = BPF_REG_7, + .src_reg = BPF_REG_7, + .off = 1, + .imm = 1, +}; + +SEC("socket") +__description("arena and stack atomic at the same instruction") +__failure __msg("same insn cannot be used with different pointers") +__arch_x86_64 +__load_if_JITed() +__naked void mixed_arena_stack_atomic(void) +{ + asm volatile (" \ + r1 = %[arena] ll; \ + r6 = r10; \ + r6 += -8; \ + r9 = 0; \ + *(u64 *)(r6 + 0) = r9; \ + r7 = 8192; \ + .8byte %[addr_space_cast]; \ + call %[bpf_get_prandom_u32]; \ + if w0 != 0 goto 1f; \ + r8 = r6; \ + goto 2f; \ +1: r8 = r7; \ +2: r9 = 1; \ + lock *(u64 *)(r8 + 0) += r9; \ + r0 = 0; \ + exit; \ +" : + : __imm_addr(arena), + __imm_insn(addr_space_cast, addr_space_cast_insn), + __imm(bpf_get_prandom_u32) + : __clobber_all); +} + static __noinline u32 __arena *check_arena_arg_nonglobal(u32 __arena *arg) { -- 2.43.0
