From nobody Sun Feb 8 05:41:41 2026 Received: from out-171.mta1.migadu.com (out-171.mta1.migadu.com [95.215.58.171]) (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 E618F2E0400; Fri, 31 Oct 2025 15:44:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761925462; cv=none; b=RjjTum04gbq9XOSFNhghZER3qysKglUYB2HSOCjqDSuWfRRpisK+kXGeMdDyXBs/UAHeH9E81FlCnNIaRLZccur/eEMgn0KkBGln5vmAynr0t30MQJLRAQf6EYsrgtO6NPikfhLxUnH7kCgFViKO5oSkaEmgv9CbisJVwo7PiiM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761925462; c=relaxed/simple; bh=kbe8hMT2OvfiqAmCP4GWUa8XfLFY+MoXA/QxrTvkDww=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c5RCmf8DNpp/A4fRDCbF4pk4iP3vv9e1XxcyBwvWs+I70Y0dvku2E5HQ2FDxcmW8+9bCnXxUhP5FIcmVUqe6KCdy+aijMJeI3W94+OkpQ+EKxKnjv89VpIMwM3oMxt7nf+Zs8mNtlK4g513ssJiLfd0sDYZYqtkkcbTVygLnPao= 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=cuMvyJcu; arc=none smtp.client-ip=95.215.58.171 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="cuMvyJcu" 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=1761925457; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9Co4HTS5uOZjTPA1XBfD/RtU0DY8DXK6Y5uls97p0Vw=; b=cuMvyJcu4+I98YZ39u4pyAHTE3nLelMYnLssuGaiI+KdXbLwBI8dVPZV12yVJpmuty/vNP OPpWxh6Zi6SorujhiEQLw50ZUcsOnXVS0LGmg+crTLBsuZr+wuDTmSUts0oePm2lGmUd/+ ErvPSV4Ks0t/nrxSbWS8gQXVNDT0Dp8= From: KaFai Wan To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, paul.chaignon@gmail.com, m.shachnai@gmail.com, henriette.herzog@rub.de, kafai.wan@linux.dev, luis.gerhorst@fau.de, harishankar.vishwanathan@gmail.com, colin.i.king@gmail.com, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH bpf-next v3 2/2] selftests/bpf: Add test for conditional jumps on same scalar register Date: Fri, 31 Oct 2025 23:41:07 +0800 Message-ID: <20251031154107.403054-3-kafai.wan@linux.dev> In-Reply-To: <20251031154107.403054-1-kafai.wan@linux.dev> References: <20251031154107.403054-1-kafai.wan@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: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" Add test cases to verify the correctness of the BPF verifier's branch analy= sis when conditional jumps are performed on the same scalar register. And make = sure that JGT does not trigger verifier BUG. Signed-off-by: KaFai Wan --- .../selftests/bpf/progs/verifier_bounds.c | 154 ++++++++++++++++++ 1 file changed, 154 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_bounds.c b/tools/te= sting/selftests/bpf/progs/verifier_bounds.c index 0a72e0228ea9..e975dc285db6 100644 --- a/tools/testing/selftests/bpf/progs/verifier_bounds.c +++ b/tools/testing/selftests/bpf/progs/verifier_bounds.c @@ -1709,4 +1709,158 @@ __naked void jeq_disagreeing_tnums(void *ctx) : __clobber_all); } =20 +SEC("socket") +__description("conditional jump on same register, branch taken") +__not_msg("20: (b7) r0 =3D 1 {{.*}} R0=3D1") +__success __log_level(2) +__retval(0) __flag(BPF_F_TEST_REG_INVARIANTS) +__naked void condition_jump_on_same_register(void *ctx) +{ + asm volatile(" \ + call %[bpf_get_prandom_u32]; \ + w8 =3D 0x80000000; \ + r0 &=3D r8; \ + if r0 =3D=3D r0 goto +1; \ + goto l1_%=3D; \ + if r0 >=3D r0 goto +1; \ + goto l1_%=3D; \ + if r0 s>=3D r0 goto +1; \ + goto l1_%=3D; \ + if r0 <=3D r0 goto +1; \ + goto l1_%=3D; \ + if r0 s<=3D r0 goto +1; \ + goto l1_%=3D; \ + if r0 !=3D r0 goto l1_%=3D; \ + if r0 > r0 goto l1_%=3D; \ + if r0 s> r0 goto l1_%=3D; \ + if r0 < r0 goto l1_%=3D; \ + if r0 s< r0 goto l1_%=3D; \ +l0_%=3D: r0 =3D 0; \ + exit; \ +l1_%=3D: r0 =3D 1; \ + exit; \ +" : + : __imm(bpf_get_prandom_u32) + : __clobber_all); +} + +SEC("socket") +__description("jset on same register, constant value branch taken") +__not_msg("7: (b7) r0 =3D 1 {{.*}} R0=3D1") +__success __log_level(2) +__retval(0) __flag(BPF_F_TEST_REG_INVARIANTS) +__naked void jset_on_same_register_1(void *ctx) +{ + asm volatile(" \ + r0 =3D 0; \ + if r0 & r0 goto l1_%=3D; \ + r0 =3D 1; \ + if r0 & r0 goto +1; \ + goto l1_%=3D; \ +l0_%=3D: r0 =3D 0; \ + exit; \ +l1_%=3D: r0 =3D 1; \ + exit; \ +" : + : __imm(bpf_get_prandom_u32) + : __clobber_all); +} + +SEC("socket") +__description("jset on same register, scalar value branch taken") +__not_msg("12: (b7) r0 =3D 1 {{.*}} R0=3D1") +__success __log_level(2) +__retval(0) __flag(BPF_F_TEST_REG_INVARIANTS) +__naked void jset_on_same_register_2(void *ctx) +{ + asm volatile(" \ + /* range [1;2] */ \ + call %[bpf_get_prandom_u32]; \ + r0 &=3D 0x1; \ + r0 +=3D 1; \ + if r0 & r0 goto +1; \ + goto l1_%=3D; \ + /* range [-2;-1] */ \ + call %[bpf_get_prandom_u32]; \ + r0 &=3D 0x1; \ + r0 -=3D 2; \ + if r0 & r0 goto +1; \ + goto l1_%=3D; \ +l0_%=3D: r0 =3D 0; \ + exit; \ +l1_%=3D: r0 =3D 1; \ + exit; \ +" : + : __imm(bpf_get_prandom_u32) + : __clobber_all); +} + +SEC("socket") +__description("jset on same register, scalar value unknown branch 1") +__msg("3: (b7) r0 =3D 0 {{.*}} R0=3D0") +__msg("5: (b7) r0 =3D 1 {{.*}} R0=3D1") +__success __log_level(2) +__flag(BPF_F_TEST_REG_INVARIANTS) +__naked void jset_on_same_register_3(void *ctx) +{ + asm volatile(" \ + /* range [0;1] */ \ + call %[bpf_get_prandom_u32]; \ + r0 &=3D 0x1; \ + if r0 & r0 goto l1_%=3D; \ +l0_%=3D: r0 =3D 0; \ + exit; \ +l1_%=3D: r0 =3D 1; \ + exit; \ +" : + : __imm(bpf_get_prandom_u32) + : __clobber_all); +} + +SEC("socket") +__description("jset on same register, scalar value unknown branch 2") +__msg("4: (b7) r0 =3D 0 {{.*}} R0=3D0") +__msg("6: (b7) r0 =3D 1 {{.*}} R0=3D1") +__success __log_level(2) +__flag(BPF_F_TEST_REG_INVARIANTS) +__naked void jset_on_same_register_4(void *ctx) +{ + asm volatile(" \ + /* range [-1;0] */ \ + call %[bpf_get_prandom_u32]; \ + r0 &=3D 0x1; \ + r0 -=3D 1; \ + if r0 & r0 goto l1_%=3D; \ +l0_%=3D: r0 =3D 0; \ + exit; \ +l1_%=3D: r0 =3D 1; \ + exit; \ +" : + : __imm(bpf_get_prandom_u32) + : __clobber_all); +} + +SEC("socket") +__description("jset on same register, scalar value unknown branch 3") +__msg("4: (b7) r0 =3D 0 {{.*}} R0=3D0") +__msg("6: (b7) r0 =3D 1 {{.*}} R0=3D1") +__success __log_level(2) +__flag(BPF_F_TEST_REG_INVARIANTS) +__naked void jset_on_same_register_5(void *ctx) +{ + asm volatile(" \ + /* range [-1;-1] */ \ + call %[bpf_get_prandom_u32]; \ + r0 &=3D 0x2; \ + r0 -=3D 1; \ + if r0 & r0 goto l1_%=3D; \ +l0_%=3D: r0 =3D 0; \ + exit; \ +l1_%=3D: r0 =3D 1; \ + exit; \ +" : + : __imm(bpf_get_prandom_u32) + : __clobber_all); +} + char _license[] SEC("license") =3D "GPL"; --=20 2.43.0