From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta0.migadu.com (out-171.mta0.migadu.com [91.218.175.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81E8C1531C1 for ; Tue, 17 Mar 2026 00:13:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773706430; cv=none; b=SSv+l9eW0H8MKCCw+SlaCKO25CTlYigf5Cpu88NCH4GtnAY8uExh9OeGOYJ9joG9C7w91qsQEtbGrgYPdRdPWFvScKJtWlxh9v/1vHBxxiWwqUTTsg9DHpid7uJYTmdkDme5p5kiFSLQGm8kri7vqdRbyfdCXYJrIxFEWZm+pJc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773706430; c=relaxed/simple; bh=gJnOQSm8yBiNonlAAEniO16wUg2fEMm8bTs0PntsHHg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Td1DjFpywMiwQ4CieGP/2B+0YDw6N1TRKlUFG8nK6lZXExfINmwlwEero0/2/jOiwIUVTcGqrJmFGs9yqdUdU2ro7VgTBRux8tmD/A2Xt26229aPvAXlk6poxJdiIRskW9bg8qFEJgL3aDShAeNAqiWtX4P1tIQkaMjtPlUMXVI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=JdNwAEnr; arc=none smtp.client-ip=91.218.175.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="JdNwAEnr" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1773706427; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BIy+xU7Dpbpw4tmyrdyKHHkWnyCzK8UDLQeLXyB75uU=; b=JdNwAEnrK32rcNXubG/fmjgTIWZp3LKZ/f1/zS79WCnS9D4Dcgi0YZtbaJ/0kAO3CVsy8H sPcyCRWUofQXTUQM1owhvtR/QvBTL6l4wxYtlbxEzIfH1ORbDeH57bDLJ9Fb5WttjKpFKy Gr0PWD37We6sCC53PGi0kjOWoRAnzzQ= From: Ihor Solodrai To: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eduard Zingerman , Martin KaFai Lau Cc: Kumar Kartikeya Dwivedi , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: [PATCH bpf v1 2/2] selftests/bpf: Add tests for bpf_throw lock leak from subprogs Date: Mon, 16 Mar 2026 17:13:25 -0700 Message-ID: <20260317001325.318004-2-ihor.solodrai@linux.dev> In-Reply-To: <20260317001325.318004-1-ihor.solodrai@linux.dev> References: <20260317001325.318004-1-ihor.solodrai@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Add test cases to ensure the verifier correctly rejects bpf_throw from subprogs when RCU or preempt locks are held: * reject_subprog_throw_rcu_lock: always-throwing subprog called while caller holds bpf_rcu_read_lock * reject_subprog_rcu_lock_throw: subprog acquires bpf_rcu_read_lock and then calls bpf_throw * reject_subprog_throw_preempt_lock: always-throwing subprog called while caller holds bpf_preempt_disable Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Ihor Solodrai --- .../selftests/bpf/progs/exceptions_fail.c | 44 +++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/exceptions_fail.c b/tools/testing/selftests/bpf/progs/exceptions_fail.c index 1dd2703c7676..9d1c560aac84 100644 --- a/tools/testing/selftests/bpf/progs/exceptions_fail.c +++ b/tools/testing/selftests/bpf/progs/exceptions_fail.c @@ -8,6 +8,9 @@ #include "bpf_experimental.h" extern void bpf_rcu_read_lock(void) __ksym; +extern void bpf_rcu_read_unlock(void) __ksym; +extern void bpf_preempt_disable(void) __ksym; +extern void bpf_preempt_enable(void) __ksym; #define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8))) @@ -346,4 +349,45 @@ int reject_exception_throw_cb_diff(struct __sk_buff *ctx) return 0; } +__noinline static int always_throws(void) +{ + bpf_throw(0); + return 0; +} + +SEC("?tc") +__failure __msg("bpf_throw cannot be used inside bpf_rcu_read_lock-ed region") +int reject_subprog_throw_rcu_lock(void *ctx) +{ + bpf_rcu_read_lock(); + always_throws(); + bpf_rcu_read_unlock(); + return 0; +} + +__noinline static int rcu_lock_then_throw(void) +{ + bpf_rcu_read_lock(); + bpf_throw(0); + return 0; +} + +SEC("?tc") +__failure __msg("bpf_throw cannot be used inside bpf_rcu_read_lock-ed region") +int reject_subprog_rcu_lock_throw(void *ctx) +{ + rcu_lock_then_throw(); + return 0; +} + +SEC("?tc") +__failure __msg("bpf_throw cannot be used inside bpf_preempt_disable-ed region") +int reject_subprog_throw_preempt_lock(void *ctx) +{ + bpf_preempt_disable(); + always_throws(); + bpf_preempt_enable(); + return 0; +} + char _license[] SEC("license") = "GPL"; -- 2.53.0