From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) (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 B1EC82D6E56 for ; Fri, 12 Sep 2025 20:47:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757710081; cv=none; b=QAm2d1KGoCXB6BsFm2IPDIiwbgem5h5U7wErT2+mJCMYdkvdPuPCgmk2t77AKYVRVpy58/3ammhzHGLrUzNfeyw+iSz4Qk8PZMjzmDztNPwCUt+tQ8yIyC7Hi9nmnNByZok9EuNDeeJnwY4XYE7BMZUGmyMosiP/XaHw8LnjyTA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757710081; c=relaxed/simple; bh=a5r1D82Y2WoGNE88dbhuZrqCxTlrKYnBKNCQdv+sI1Q=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VvMKVOwj2BajcTf9L2T8wslLXL5B189mTTLwZeWKb2PYowrWri0NOfrtsIjd3UqiCLFdEnhU3W8ITa2YOqunq14uwdzmkMnp9wgYH7KMU1C6fAeMUYEWqitddb7cPlMXSAaytKpwTdZ/PYx90b2y9DAhtY+PJGkfrYeNM8cbFOo= 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=Ay5gNk+T; arc=none smtp.client-ip=209.85.128.45 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="Ay5gNk+T" Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-45dd7b15a64so21302465e9.0 for ; Fri, 12 Sep 2025 13:47:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1757710076; x=1758314876; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=ztodRZzqZ7LwwLlFxMHp4gp6whyJBQuaH7JG6HpRU/w=; b=Ay5gNk+TlZZC5WsVXpdZzb0LGcNZHY3+FScsegHImpTMGiFKyenG22jTe+TXZDMkk8 Q33ce0pdgxb/aiQ0kUn7L4u8EW50kep/tsGZz6RdWEswLmQmgv5qTwYufUJCxZm2uK1M jT2ra4GmL8qA3mLQcTCuT8A4euoOpuUR4xJwIa3Ukn/dMGj3bbCHFhMk+UM80JanO/qg 7MLIUG60PjLXpaIX69kqKJpmN7+VT7Y+NycF/+VV9EIxGEJCKHpXcmZ0HmiZ8Zh4xIfm 71hQh3QXNmzcR4mxxoyia7NEOO+2kWzS/mlprYmm8/DNsCbFSnOJrOtzctBzGkv1SyOu qoJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757710076; x=1758314876; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=ztodRZzqZ7LwwLlFxMHp4gp6whyJBQuaH7JG6HpRU/w=; b=X43lgKYYSSxOM4HAUl8PpO+HXLmbyd35SSUm5ge3P1fmNnGx+GWGk30PauNzeEaOk7 Nwr3CMD50i6rJdNULx9dFthiBak//wYzpWABMnnTC6ybtZAc1ASCmPRmZwm2E1fv4/Ou ba+4+0Lu+LOHMiYkAYSbaoQFKbCCFUCW4nmbeES9rgZvhCME4VexAuLSgC2k8DepPDI8 k1YTSmQSDiUToDXHrx8aNTpBFne5thS8H1FohduEeBpNPLPeHimwtBxylANL908enAUb GW1qNLiHbVfJ1w7RekCdTEsT1Ad+Sh+fhSQR9EI5ZTfEqp8eIlwfNhEHlE3ceyjGx3PS Pxnw== X-Forwarded-Encrypted: i=1; AJvYcCXrDJE27enb5JG/xiiBmehlk4g0UjCyMYon97Io0Cu93x3vF6aqZsdCfhT2zYRs66E1xuMFlkU=@vger.kernel.org X-Gm-Message-State: AOJu0YycF7jYzXxPWfd82IUj18e3kZBFuoFMLvA5A6m0670Kv8n+2BDw 0H8nx/Ba/PGFC4f6wOkg8xoXgj8fKUC80odx8cugfYmbol8Ppxck6QCK X-Gm-Gg: ASbGncu8VsO0aCWhynD3AR/vtpJBAdS5c8WjOLyA0xk7ScgE+ssrKL5SktrMgvgPbcm ePYNGzQe2k85/4wdQjTZqA6/4n7b8gjFmrEuerUc3bSbjHowjYF+IX+P2mWdOdhqct7OuY1SP9r +vCCqW4hoAhZ6DOcLZhCW1O7+kyTanE0AeKEsuiZwwTOcV3H6eh3UbmhIWARCRNVd5mZwEvG+0/ bBmaQGGR9pCUBpwT6t6Uj65ef7TuAZbTIymo8Qy9mkFKgFDGbAhYRvUpZX2wd2bhW/dRYQBWcVW itLM0Erj8wD+hB3PZEhrC52IDm4VcjLW2rXRwT6CzzsMMR1UpaDV4X94H3+j9I37guRMr+9SS59 diEym5tCC8+m2oPrL9PeuFdNpFSGGwrxiPBRK0Pt8gMh0KHeyCg== X-Google-Smtp-Source: AGHT+IFIvkjy8Vwo+tcss+tuzUrJigzqjS7F4UVyfQ+Mr6yldJrMZviznywA0j6s22x0kQNAy0i8hQ== X-Received: by 2002:a05:600c:3b93:b0:45b:8ac2:9761 with SMTP id 5b1f17b1804b1-45f2698a026mr4412855e9.13.1757710075861; Fri, 12 Sep 2025 13:47:55 -0700 (PDT) Received: from krava (89-40-234-69.wdsl.neomedia.it. [89.40.234.69]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45e015ad780sm38311015e9.10.2025.09.12.13.47.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Sep 2025 13:47:55 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Fri, 12 Sep 2025 22:47:52 +0200 To: Stephen Rothwell Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra , Daniel Borkmann , Alexei Starovoitov , Andrii Nakryiko , Jiawei Zhao , bpf , Networking , Linux Kernel Mailing List , Linux Next Mailing List Subject: Re: linux-next: manual merge of the tip tree with the bpf-next tree Message-ID: References: <20250912124059.0428127b@canb.auug.org.au> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250912124059.0428127b@canb.auug.org.au> On Fri, Sep 12, 2025 at 12:40:59PM +1000, Stephen Rothwell wrote: > Hi all, > > Today's linux-next merge of the tip tree got a conflict in: > > tools/testing/selftests/bpf/prog_tests/usdt.c > > between commit: > > 69424097ee10 ("selftests/bpf: Enrich subtest_basic_usdt case in selftests to cover SIB handling logic") > > from the bpf-next tree and commit: > > 875e1705ad99 ("selftests/bpf: Add optimized usdt variant for basic usdt test") > > from the tip tree. > > I fixed it up (see below) and can carry the fix as necessary. This > is now fixed as far as linux-next is concerned, but any non trivial > conflicts should be mentioned to your upstream maintainer when your tree > is submitted for merging. You may also want to consider cooperating > with the maintainer of the conflicting tree to minimise any particularly > complex conflicts. hi, fwiw the conflict was mentioned in here: https://lore.kernel.org/bpf/aMAiMrLlfmG9FbQ3@krava/ the fix looks good, thanks jirka > > -- > Cheers, > Stephen Rothwell > > diff --cc tools/testing/selftests/bpf/prog_tests/usdt.c > index 615e9c3e93bf,833eb87483a1..000000000000 > --- a/tools/testing/selftests/bpf/prog_tests/usdt.c > +++ b/tools/testing/selftests/bpf/prog_tests/usdt.c > @@@ -40,73 -40,20 +40,80 @@@ static void __always_inline trigger_fun > } > } > > +#if defined(__x86_64__) || defined(__i386__) > +/* > + * SIB (Scale-Index-Base) addressing format: "size@(base_reg, index_reg, scale)" > + * - 'size' is the size in bytes of the array element, and its sign indicates > + * whether the type is signed (negative) or unsigned (positive). > + * - 'base_reg' is the register holding the base address, normally rdx or edx > + * - 'index_reg' is the register holding the index, normally rax or eax > + * - 'scale' is the scaling factor (typically 1, 2, 4, or 8), which matches the > + * size of the element type. > + * > + * For example, for an array of 'short' (signed 2-byte elements), the SIB spec would be: > + * - size: -2 (negative because 'short' is signed) > + * - scale: 2 (since sizeof(short) == 2) > + * > + * The resulting SIB format: "-2@(%%rdx,%%rax,2)" for x86_64, "-2@(%%edx,%%eax,2)" for i386 > + */ > +static volatile short array[] = {-1, -2, -3, -4}; > + > +#if defined(__x86_64__) > +#define USDT_SIB_ARG_SPEC -2@(%%rdx,%%rax,2) > +#else > +#define USDT_SIB_ARG_SPEC -2@(%%edx,%%eax,2) > +#endif > + > +unsigned short test_usdt_sib_semaphore SEC(".probes"); > + > +static void trigger_sib_spec(void) > +{ > + /* > + * Force SIB addressing with inline assembly. > + * > + * You must compile with -std=gnu99 or -std=c99 to use the > + * STAP_PROBE_ASM macro. > + * > + * The STAP_PROBE_ASM macro generates a quoted string that gets > + * inserted between the surrounding assembly instructions. In this > + * case, USDT_SIB_ARG_SPEC is embedded directly into the instruction > + * stream, creating a probe point between the asm statement boundaries. > + * It works fine with gcc/clang. > + * > + * Register constraints: > + * - "d"(array): Binds the 'array' variable to %rdx or %edx register > + * - "a"(0): Binds the constant 0 to %rax or %eax register > + * These ensure that when USDT_SIB_ARG_SPEC references %%rdx(%edx) and > + * %%rax(%eax), they contain the expected values for SIB addressing. > + * > + * The "memory" clobber prevents the compiler from reordering memory > + * accesses around the probe point, ensuring that the probe behavior > + * is predictable and consistent. > + */ > + asm volatile( > + STAP_PROBE_ASM(test, usdt_sib, USDT_SIB_ARG_SPEC) > + : > + : "d"(array), "a"(0) > + : "memory" > + ); > +} > +#endif > + > - static void subtest_basic_usdt(void) > + static void subtest_basic_usdt(bool optimized) > { > LIBBPF_OPTS(bpf_usdt_opts, opts); > struct test_usdt *skel; > struct test_usdt__bss *bss; > - int err, i; > + int err, i, called; > + const __u64 expected_cookie = 0xcafedeadbeeffeed; > > + #define TRIGGER(x) ({ \ > + trigger_func(x); \ > + if (optimized) \ > + trigger_func(x); \ > + optimized ? 2 : 1; \ > + }) > + > skel = test_usdt__open_and_load(); > if (!ASSERT_OK_PTR(skel, "skel_open")) > return; > @@@ -126,22 -73,13 +133,22 @@@ > if (!ASSERT_OK_PTR(skel->links.usdt0, "usdt0_link")) > goto cleanup; > > +#if defined(__x86_64__) || defined(__i386__) > + opts.usdt_cookie = expected_cookie; > + skel->links.usdt_sib = bpf_program__attach_usdt(skel->progs.usdt_sib, > + 0 /*self*/, "/proc/self/exe", > + "test", "usdt_sib", &opts); > + if (!ASSERT_OK_PTR(skel->links.usdt_sib, "usdt_sib_link")) > + goto cleanup; > +#endif > + > - trigger_func(1); > + called = TRIGGER(1); > > - ASSERT_EQ(bss->usdt0_called, 1, "usdt0_called"); > - ASSERT_EQ(bss->usdt3_called, 1, "usdt3_called"); > - ASSERT_EQ(bss->usdt12_called, 1, "usdt12_called"); > + ASSERT_EQ(bss->usdt0_called, called, "usdt0_called"); > + ASSERT_EQ(bss->usdt3_called, called, "usdt3_called"); > + ASSERT_EQ(bss->usdt12_called, called, "usdt12_called"); > > - ASSERT_EQ(bss->usdt0_cookie, 0xcafedeadbeeffeed, "usdt0_cookie"); > + ASSERT_EQ(bss->usdt0_cookie, expected_cookie, "usdt0_cookie"); > ASSERT_EQ(bss->usdt0_arg_cnt, 0, "usdt0_arg_cnt"); > ASSERT_EQ(bss->usdt0_arg_ret, -ENOENT, "usdt0_arg_ret"); > ASSERT_EQ(bss->usdt0_arg_size, -ENOENT, "usdt0_arg_size"); > @@@ -225,18 -163,9 +232,19 @@@ > ASSERT_EQ(bss->usdt3_args[1], 42, "usdt3_arg2"); > ASSERT_EQ(bss->usdt3_args[2], (uintptr_t)&bla, "usdt3_arg3"); > > +#if defined(__x86_64__) || defined(__i386__) > + trigger_sib_spec(); > + ASSERT_EQ(bss->usdt_sib_called, 1, "usdt_sib_called"); > + ASSERT_EQ(bss->usdt_sib_cookie, expected_cookie, "usdt_sib_cookie"); > + ASSERT_EQ(bss->usdt_sib_arg_cnt, 1, "usdt_sib_arg_cnt"); > + ASSERT_EQ(bss->usdt_sib_arg, nums[0], "usdt_sib_arg"); > + ASSERT_EQ(bss->usdt_sib_arg_ret, 0, "usdt_sib_arg_ret"); > + ASSERT_EQ(bss->usdt_sib_arg_size, sizeof(nums[0]), "usdt_sib_arg_size"); > +#endif > + > cleanup: > test_usdt__destroy(skel); > + #undef TRIGGER > } > > unsigned short test_usdt_100_semaphore SEC(".probes");