From 175a58668e2d5e96c571177fc7a0d8997bfbb205 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Thu, 20 Aug 2026 04:20:19 +0200 Subject: [PATCH] selftests/bpf: Test invalid DW LDSX diagnostics An invalid BPF_MEMSX | BPF_DW instruction can reach Program Structure diagnostics before opcode validation when placed at the end of a subprogram. Exercise this path and require the disassembler fallback so table bounds regressions are caught. Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20260820022020.3450479-3-memxor@gmail.com --- tools/testing/selftests/bpf/progs/verifier_cfg.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_cfg.c b/tools/testing/selftests/bpf/progs/verifier_cfg.c index c1f55e1d80a4..3c3bb03e8217 100644 --- a/tools/testing/selftests/bpf/progs/verifier_cfg.c +++ b/tools/testing/selftests/bpf/progs/verifier_cfg.c @@ -3,6 +3,7 @@ #include #include +#include "../../../include/linux/filter.h" #include "bpf_misc.h" SEC("socket") @@ -55,6 +56,19 @@ __naked void out_of_range_jump2(void) " ::: __clobber_all); } +SEC("socket") +__description("invalid DW LDSX instruction in diagnostics") +__failure __msg("BUG_ldx_99") +__log_level(2) +__naked void invalid_dw_ldsx(void) +{ + asm volatile (" \ + .8byte %[ldsx_dw]; \ +" : + : __imm_insn(ldsx_dw, BPF_RAW_INSN(BPF_LDX | BPF_MEMSX | BPF_DW, BPF_REG_0, BPF_REG_0, 0, 0)) + : __clobber_all); +} + SEC("socket") __description("loop (back-edge)") __failure __msg("unreachable insn 1")