From 83608e303b95d07afba1c15da0b5d9e513c2f15a Mon Sep 17 00:00:00 2001 From: Ning Ding Date: Mon, 10 Aug 2026 20:59:54 -0700 Subject: [PATCH] bpf: Compare iterator types during state pruning An iterator stack slot can be MEM_RCU or PTR_UNTRUSTED. These states must not be equal, or the verifier can prune an unsafe path. Compare the pointer type for STACK_ITER slots. Fixes: dfab99df147b ("bpf: teach the verifier to enforce css_iter and task_iter in RCU CS") Signed-off-by: Ning Ding Acked-by: Eduard Zingerman Link: https://patch.msgid.link/20260811035955.132989-2-dingning04@gmail.com Signed-off-by: Eduard Zingerman --- kernel/bpf/states.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/states.c b/kernel/bpf/states.c index ea2153cf28d0..4e6aafad33bd 100644 --- a/kernel/bpf/states.c +++ b/kernel/bpf/states.c @@ -812,7 +812,8 @@ static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old, * infinite loop check triggering, see * iter_active_depths_differ() */ - if (old_reg->iter.btf != cur_reg->iter.btf || + if (old_reg->type != cur_reg->type || + old_reg->iter.btf != cur_reg->iter.btf || old_reg->iter.btf_id != cur_reg->iter.btf_id || old_reg->iter.state != cur_reg->iter.state || /* ignore {old_reg,cur_reg}->iter.depth, see above */