From: Ning Ding <dingning04@gmail.com>
To: bpf@vger.kernel.org
Cc: memxor@gmail.com, ast@kernel.org, daniel@iogearbox.net,
andrii@kernel.org, linux-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org, shuah@kernel.org,
Ning Ding <dingning04@gmail.com>
Subject: [PATCH bpf-next 1/2] bpf: Compare iterator types during state pruning
Date: Thu, 6 Aug 2026 17:43:19 -0700 [thread overview]
Message-ID: <20260807004320.134069-2-dingning04@gmail.com> (raw)
In-Reply-To: <20260807004320.134069-1-dingning04@gmail.com>
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 <dingning04@gmail.com>
---
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 ea2153cf28d0a..4e6aafad33bd2 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 */
--
2.43.0
next prev parent reply other threads:[~2026-08-07 0:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-07 0:43 [PATCH bpf-next 0/2] bpf: Compare iterator types during state pruning Ning Ding
2026-08-07 0:43 ` Ning Ding [this message]
2026-08-07 0:43 ` [PATCH bpf-next 2/2] selftests/bpf: Test RCU iterator " Ning Ding
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