From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F928348C7B for ; Tue, 18 Aug 2026 19:56:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787082988; cv=none; b=qHAOIaIO6UNrj/O/HVmvWh6gRF/lzLZtqADm0iqibrFDLr94dELMylh4JoTEw0dO0dAx0uP2bQDsvlWwmgVqMV+EHx+OiHk/56jr7CZ5ViwvabBfCktyRpwAJ2EmhNaYij/g5XjllNLqF1P33ba/ZNpcB7gwY/6DNXLywZemSUw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787082988; c=relaxed/simple; bh=8IH10OjJZB/mtZdH6fmGqFSUirbS+Exj18SWzs9jBGU=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=jdUwMlkJiiFMUlDoCBbztAAZgIDnyFOQTk4V3GlF0FZUbKKKLsRQx3DQQergH+tBuv1UfeIZUPJs5itdSgjJnk7ZITe68XRwkm4Ojjv++BIDKtDi58vvtYZR9UpEB843GOfuPR/dzDm4J18dV6LTx4FvsDlD9k1WJTwnPQnrDK0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=jF1OaZDj; arc=none smtp.client-ip=209.85.214.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jF1OaZDj" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-2caed617615so2446875ad.3 for ; Tue, 18 Aug 2026 12:56:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787082987; x=1787687787; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:content-type :references:in-reply-to:date:cc:to:from:subject:message-id:from:to :cc:subject:date:message-id:reply-to:content-type; bh=MwsjfYvjhLLXvhbkk9VLjuUHWqsTTdTeOI61TJBjUdk=; b=jF1OaZDj00nwOzsynVGw6C4vixLhAM+FfIbShX9Bc/a3gULgU5+zI36nxCdunNd/qG 4w7KqOjCXtXqSQbUd6bLhuogGPX2n8ki7KRmmOtTTSuylcAs35PtnuGUY+RYijVjph2Z WsgSiTB3wVBcClAodn16xvpwFGVrsDNvh+tLeWPXboXHb7PhMXbKStt4Elt8fk/O7TFB tUvmlmRNdjKBvbnoNxSLoqVSq64NgXOigHArrcTiZh3SwBi8CPid76u0W/lsX2mkrXjp JOjeKLSGJEVZhSnNuhCYFWtfn9RFLqFE/F3PMhBoWwr6KM+0tGLRCWTunWvO5VBpN9XJ fYKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787082987; x=1787687787; h=mime-version:user-agent:content-transfer-encoding:content-type :references:in-reply-to:date:cc:to:from:subject:message-id:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=MwsjfYvjhLLXvhbkk9VLjuUHWqsTTdTeOI61TJBjUdk=; b=pCNM7H4YAARBC/cqa2F6RzsMe9q/XQkQuVre/ZcZjVk2usby1TYg/RjniqdMt+4zwv QhmBiy6Xj8DRrMGXCgpyKGI7IjOEVesYLLUoZz2KDSd+KjoSLWM3kBlvR2N8KQPpeElL ve3qm3LhvwfkL2iw8oGEUWC+ENJRMiwweq5j5jifz6Bk4eCOAxB0PNJ6cEPmEz5t2B06 l43e+MLUiCEPb/Z6vV30MboNZkoLd3LATHbbocXb23v/edqBLgvehrroPhgxE1Dg3VI3 TBGLpoNZUok+NjfZV3+ftPiYBhVMqIq+22+cCmeBpCHNpAosSSf5yjyoN6jhQOrd0Bor nOfA== X-Forwarded-Encrypted: i=1; AHgh+RphAyWQn6kUaHUC0HMiS3uGUsZ2Ile1+NK702SqXQWYMsQh2ZjBfwwuo13cGqdndOM1jdK9EuXXE5RI+zo=@vger.kernel.org X-Gm-Message-State: AOJu0Yy5XdMs+G5ew9yrPE0jSiwL9TnXQz4fWrSDl/pxEuRf41Wlh4Jk Vv7/9u7pC8cj9Vm6M5nLwJmwFH+2wE7XzIbsX97UPbIvb++8K8Qmf6Hw X-Gm-Gg: AR+sD10sFAyTZ6O1cr67tkHNqCjYXW/1ZJtYLYAimixQAHSxn4YugW0OtRMHp7ILmE/ In1clbdBtwhQvRVRwBIlcjJkmiSPpn8vXWksaJWBijbjihtAbksu9mGmCBmvd3KmzAwMEUz5d/U vxHSC9UiyIvnwtJE1Q9kJRFHbEBLpBb5FUeaPM8M+nCXgV0DtIkBsyTpwpFkXqW0hzM5EkB8Ewx dmJ197l0xZ5BCnd/ZBt4cWNuqRMt1AZ5BrIYb8gfsEOr2QCGZYCI6Ol9MfTqmpGniSQf6bnGpC7 Id487Ce0899lMYrc1uMutjesN4hxcThEKCGWml4yzWT3QJXhz5EIeEFWBmPE+CxK31muQqDo/2w SlLQYjid3XFAFAUqKsFJcEP6ZvebEvW1LSW6tUPfzld1N7K8t+XQ9Qc4C5rX0iE/f1XyDGMCWRq T/dod+Rq4hYjkZjhNu4LBIejk9icCLlTYQdpdksMT9hiqrCMnYTeBDt3XoZvxRVX2FccI9P1/xk us/qqFKJowNvQN/X/ZV9DKSJdfgUTD7 X-Received: by 2002:a17:902:d483:b0:2d3:6fac:d67c with SMTP id d9443c01a7336-2d5f6cb7623mr3131945ad.10.1787082986700; Tue, 18 Aug 2026 12:56:26 -0700 (PDT) Received: from [192.168.0.13] ([38.34.87.7]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d5bb519678sm21011025ad.31.2026.08.18.12.56.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Aug 2026 12:56:26 -0700 (PDT) Message-ID: Subject: Re: [PATCH bpf-next v2 2/2] selftests/bpf: Cover mixed arena and stack atomics From: Eduard Zingerman To: Vineet Gupta , Yiyang Chen , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Shuah Khan Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Date: Tue, 18 Aug 2026 12:56:23 -0700 In-Reply-To: References: <20260816-bpf-next-038-mixed-atomic-v1-v2-0-4644c1886dbc@mails.tsinghua.edu.cn> <20260816-bpf-next-038-mixed-atomic-v1-v2-2-4644c1886dbc@mails.tsinghua.edu.cn> <123a014b2b4ecd7d19cbdfe62c62d994e612b6f0.camel@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2-10 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-08-18 at 12:35 -0700, Vineet Gupta wrote: > On 8/16/26 4:36 PM, Eduard Zingerman wrote: > > On Sun, 2026-08-16 at 16:17 -0700, Eduard Zingerman wrote: > > > On Sun, 2026-08-16 at 10:56 +0000, Yiyang Chen wrote: > > > > Add a verifier test with one atomic RMW instruction reached through > > > > PTR_TO_ARENA and PTR_TO_STACK paths. The verifier must reject the > > > > shared instruction with the existing incompatible-pointer diagnosti= c. > > > >=20 > > > > Signed-off-by: Yiyang Chen > > > > --- > > > > =C2=A0=C2=A0tools/testing/selftests/bpf/progs/verifier_arena.c | 39= ++++++++++++++++++++++ > > > > =C2=A0=C2=A01 file changed, 39 insertions(+) > > > >=20 > > > > diff --git a/tools/testing/selftests/bpf/progs/verifier_arena.c b/t= ools/testing/selftests/bpf/progs/verifier_arena.c > > > > index b241bbcf54a8a..b22bab33301ab 100644 > > > > --- a/tools/testing/selftests/bpf/progs/verifier_arena.c > > > > +++ b/tools/testing/selftests/bpf/progs/verifier_arena.c > > > > @@ -637,6 +637,45 @@ int non_arena_ptr_add_to_arena_ptr(void *ctx) > > > > =C2=A0=20 > > > > =C2=A0=C2=A0#endif > > > > =C2=A0=20 > > > > +static const struct bpf_insn addr_space_cast_insn =3D { > > > > + .code =3D 0xbf, > > > > + .dst_reg =3D BPF_REG_7, > > > > + .src_reg =3D BPF_REG_7, > > > > + .off =3D 1, > > > > + .imm =3D 1, > > > > +}; > > > > + > > > > +SEC("socket") > > > > +__description("arena and stack atomic at the same instruction") > > > > +__failure __msg("same insn cannot be used with different pointers"= ) > > > > +__arch_x86_64 > > > > +__load_if_JITed() > > > > +__naked void mixed_arena_stack_atomic(void) > > > > +{ > > > > + asm volatile (" \ > > > > + r1 =3D %[arena] ll; \ > > > > + r6 =3D r10; \ > > > > + r6 +=3D -8; \ > > > > + r9 =3D 0; \ > > > > + *(u64 *)(r6 + 0) =3D r9; \ > > > > + r7 =3D 8192; \ > > > > + .8byte %[addr_space_cast]; \ > > > I'm going to fix this to: > > >=20 > > > r7 =3D addr_space_cast(r7, 0, 1); \ > > >=20 > > > as in the test case above. > > > Waiting for CI [1]. > > >=20 > > > [1] https://github.com/kernel-patches/bpf/pull/13325 > >=20 > > A...and it requires another exception for GCC-BPF: > > https://github.com/kernel-patches/bpf/blob/bpf-next_base/ci/vmtest/conf= igs/DENYLIST.test_progs-bpf_gcc > >=20 > > Ihor, it's a third time GCC-BPF strikes this weekend. > > What do people think about downgrading it to may-fail until the > > DENYLIST decreases to something reasonable? >=20 > While bpf-gcc is improving, slowly, we can in parallel do alittle better= =20 > on test hygiene as well. In this case by correctly bracketing the tests= =20 > with _BPF_FEATURE_XXX. Yes, that's what I ended up doing. Should have paid attention to the #if .. #endif bracket used by the textually preceding test. Sorry for lashing out. > Co-incidently I have a series in works from an accidental discovery of= =20 > llvm-only testing coverage (rely solely on __clang_version macro) which= =20 > I'll follow up on the list shortly. >=20 > Thx, > -Vineet >=20 >=20 > >=20 > > Anyway, I'll wrap-up with this patch-set in the evening. > >=20 > > > > + call %[bpf_get_prandom_u32]; \ > > > > + if w0 !=3D 0 goto 1f; \ > > > > + r8 =3D r6; \ > > > > + goto 2f; \ > > > > +1: r8 =3D r7; \ > > > > +2: r9 =3D 1; \ > > > > + lock *(u64 *)(r8 + 0) +=3D r9; \ > > > > + r0 =3D 0; \ > > > > + exit; \ > > > > +" : > > > > + : __imm_addr(arena), > > > > + =C2=A0 __imm_insn(addr_space_cast, addr_space_cast_insn), > > > > + =C2=A0 __imm(bpf_get_prandom_u32) > > > > + : __clobber_all); > > > > +} > > > > + > > > > =C2=A0=C2=A0static __noinline > > > > =C2=A0=C2=A0u32 __arena *check_arena_arg_nonglobal(u32 __arena *arg= ) > > > > =C2=A0=C2=A0{