Atomic RMW verification records an instruction pointer type only when the current destination is PTR_TO_ARENA. A second path can therefore reach the same instruction with an ordinary pointer without comparing it against the saved arena type. The post-verification fixup uses the saved type to rewrite the instruction to BPF_PROBE_ATOMIC for every path. Record the actual destination type for all atomic RMW paths so the existing mismatch check rejects incompatible uses of one instruction. Fixes: d503a04f8bc0 ("bpf: Add support for certain atomics in bpf_arena to x86 JIT") Signed-off-by: Yiyang Chen --- kernel/bpf/verifier.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 164d16c243ca6..3d672f6665bec 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6509,11 +6509,9 @@ static int check_atomic_rmw(struct bpf_verifier_env *env, if (err) return err; - if (is_arena_reg(env, insn->dst_reg)) { - err = save_aux_ptr_type(env, PTR_TO_ARENA, false); - if (err) - return err; - } + err = save_aux_ptr_type(env, dst_reg->type, false); + if (err) + return err; /* Check whether we can write into the same memory. */ err = check_mem_access(env, env->insn_idx, dst_reg, argno_from_reg(insn->dst_reg), insn->off, BPF_SIZE(insn->code), BPF_WRITE, -1, true, false); -- 2.43.0