From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-182.mta1.migadu.com (out-182.mta1.migadu.com [95.215.58.182]) (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 9CDB2946A for ; Fri, 20 Mar 2026 00:08:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773965308; cv=none; b=n4yBmkCsd8e82ZU2ocE/4VEwniadGn6BOnl+jkEUZFUyk3NHdCcS99EQmxBxvYHB6VjieQalvfh/OK77Kjb+UmI8hiAr0TjXzn/UgACpdIW9yZUqUhpspZV+gJI+55Ammwk5eKNWG7dpvfC+rf8gnPo2RjEt4aqiuHpq2JyhadE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773965308; c=relaxed/simple; bh=N7zW9MTwRn/LA6kK6L7yrbmYk9SkgjLkPb64CkuO7tY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=grtorq7dtud15ekFgnYNTxAy77X5To2g2X1cQome/+h/zqfat94MYirm06HapfJI8bRiW6usXHBVFjxA5gDp5rAUEfnqtS8bkD25Zoxe2MiLU3F2nbCX4vw2vP7nFqklaQrEbjZL86YKcZKgNVQwVU+At4yQdUnxvfgsvPofoNI= 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=U3DTRztP; arc=none smtp.client-ip=95.215.58.182 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="U3DTRztP" 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=1773965304; 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=mlJAz/MS2GqrFQaBqGoSqbQAjVawX3I4YWIFnTBvWNg=; b=U3DTRztPUk6qeWQy53TuJbyEn3ntfMGnQE73DHJXxHhUKOzA521NXKugNy2Yv4Wijr1PCB BpRwdvykzc/Y6DpC/qeUP7XNMOhwie7neb/0t0ftTdympb5Vnxv5TAjC6knIW63ioGyUXe OsE05UIqwnnZ4FGSgMg++G8fZuptvyk= 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 v2 2/2] selftests/bpf: Add tests for bpf_throw lock leak from subprogs Date: Thu, 19 Mar 2026 17:08:09 -0700 Message-ID: <20260320000809.643798-2-ihor.solodrai@linux.dev> In-Reply-To: <20260320000809.643798-1-ihor.solodrai@linux.dev> References: <20260320000809.643798-1-ihor.solodrai@linux.dev> Precedence: bulk X-Mailing-List: bpf@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, preempt, or IRQ locks are held: * 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 * reject_subprog_throw_irq_lock: always-throwing subprog called while caller holds bpf_local_irq_save Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Ihor Solodrai --- .../selftests/bpf/progs/exceptions_fail.c | 47 +++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/exceptions_fail.c b/tools/testing/selftests/bpf/progs/exceptions_fail.c index d7f1c492e3dd..9ea1353488d7 100644 --- a/tools/testing/selftests/bpf/progs/exceptions_fail.c +++ b/tools/testing/selftests/bpf/progs/exceptions_fail.c @@ -9,6 +9,10 @@ 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; +extern void bpf_local_irq_save(unsigned long *) __ksym; +extern void bpf_local_irq_restore(unsigned long *) __ksym; #define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8))) @@ -349,4 +353,47 @@ int reject_exception_throw_cb_diff(struct __sk_buff *ctx) return 0; } +__noinline static int always_throws(void) +{ + bpf_throw(0); + 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; +} + +SEC("?tc") +__failure __msg("bpf_throw cannot be used inside bpf_local_irq_save-ed region") +int reject_subprog_throw_irq_lock(void *ctx) +{ + unsigned long flags; + + bpf_local_irq_save(&flags); + always_throws(); + bpf_local_irq_restore(&flags); + return 0; +} + char _license[] SEC("license") = "GPL"; -- 2.53.0