From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9CF43143736; Wed, 16 Oct 2024 02:06:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729044397; cv=none; b=eowrluVFu3JFQGlFoWLOactEg8AA55PjgIF9Ds7VJwPXaMem4nZ+59Qdqbch3sPSrp+Nov1cw/1a2Me8A7DT7I3H9/VcO1NquX0T0PFqhkxHhl1niR0XuMCB65TDAaCpekaIqBETUqY8hlGyzOa/eY+IKaVq2aGLrwK3JD2hQUc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729044397; c=relaxed/simple; bh=aEa7/Y7h65bZMBSJIpYtv9760VAAbwP31QCb01yRdjA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VDTXAHZF7yEk1sLdmXL32KK1wzZMBIgLdECWirLWFO7tb2cqF4Cxe3Oaryew2EkVEnx2o0ugy449EHDHEXCtwUxD7osmyfHv2A1wJSK3VrBrAJ2ArYCaoj8xoHOpfXMQiPpH0EeAx7/XMeMYC/k0X7Ksqpws4ZRfOZcl3SoNZTM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lu4jIqXj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lu4jIqXj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8FE6AC4CEC6; Wed, 16 Oct 2024 02:06:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729044397; bh=aEa7/Y7h65bZMBSJIpYtv9760VAAbwP31QCb01yRdjA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lu4jIqXjVEcCPIl2hjDQQEc5SArSAbBioZHYouw2ydTQQ2+rSyBxG+gk9YvGr3aBx 1xCvbS4Nw8pUQpee+Kk//aYv1tPsY6hDCmthQS+B1b/l7ukbZDY7iqu9jjasFxhcfb gmdEOnUm7IQUq714miBEC4JBIjOVKUZsFNlgWiSyjd4r1719q85xXcxV2Wy9mOagFb 4jn4x77/J8htcZHkz4AJxbzZgAQ8kFnfiIAjm17IR2DX6RN/FD5Bjzu/kgFfUJlW13 DWem1taJVt7iANN+7yEaUTD53n0sT6RNh+KT0yOPZDZjiXiH/zkyTuRxM59bwvFAFe +CL8ZpCUda2aQ== Date: Tue, 15 Oct 2024 19:06:35 -0700 From: Namhyung Kim To: Arnaldo Carvalho de Melo Cc: Song Liu , Howard Chu , Andrea Righi , peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, james.clark@linaro.org, alan.maguire@oracle.com Subject: Re: [PATCH v2 0/2] perf trace: Fix support for the new BPF feature in clang 12 Message-ID: References: <20241011021403.4089793-1-howardchu95@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hi Arnaldo, On Tue, Oct 15, 2024 at 05:37:38PM -0300, Arnaldo Carvalho de Melo wrote: > On Tue, Oct 15, 2024 at 04:58:56PM -0300, Arnaldo Carvalho de Melo wrote: > > So I'm trying adding extra bounds checking, marking the index as > > volatile, adding compiler barriers, etc, all the fun with the verifier, > > but got distracted with other stuff, coming back to this now. > > > Ok, the following seems to do the trick: > > > [acme@dell-per740-01 perf-tools]$ git diff > > diff --git a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c > > index 3b30aa74a3ae..ef87a04ff8d0 100644 > > --- a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c > > +++ b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c > > @@ -486,6 +486,7 @@ static int augment_sys_enter(void *ctx, struct syscall_enter_args *args) > > augmented = true; > > } else if (size < 0 && size >= -6) { /* buffer */ > > index = -(size + 1); > > + index &= 7; // To satisfy the bounds checking with the verifier in some kernels > > aug_size = args->args[index]; > > > > if (aug_size > TRACE_AUG_MAX_BUF) > > > > I'll now test it without Howard's patch to see if it fixes the RHEL8 + > > clang 17 case. > > It works with this one-liner + the simplified patch from Howard and also > on this other system (RHEL9), as well as with Fedora 40, it would be > nice if someone could test with clang 16 and report back the version of > the kernel tested as well as the distro name/release, that way I can try > to get my hands on such as system and test there as well. > > Its all at: > > https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools.git tmp.perf-tools > > This is the current set of patches that when further tested will go to > Linus for v6.12: > > ⬢[acme@toolbox perf-tools]$ git log --oneline torvalds/master.. > ff14baa7a290bf42 (HEAD -> perf-tools, x1/perf-tools, perf-tools/tmp.perf-tools) perf trace augmented_raw_syscalls: Add more checks to pass the verifier > 46180bec048aad85 perf trace augmented_raw_syscalls: Add extra array index bounds checking to satisfy some BPF verifiers > 45d1aadac64869a2 perf build: Change the clang check back to 12.0.1 Wouldn't it be better to have this change after fixing the verifier issues in the later commits? > 4e21679eb81b5f0d perf trace: The return from 'write' isn't a pid > 2d2314d4b09b5ed9 tools headers UAPI: Sync linux/const.h with the kernel headers > ⬢[acme@toolbox perf-tools]$ I guess you also need the syscalltbl fix from Jiri Slaby. https://lore.kernel.org/linux-perf-users/3a592835-a14f-40be-8961-c0cee7720a94@kernel.org/ Thanks, Namhyung > > [root@nine ~]# uname -a > Linux nine 5.14.0-427.31.1.el9_4.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Aug 9 14:06:03 EDT 2024 x86_64 x86_64 x86_64 GNU/Linux > [root@nine ~]# perf trace -e *sleep* sleep 1.234567890 > 0.000 (1234.742 ms): sleep/80014 clock_nanosleep(rqtp: 0x7ffc55b11240, rmtp: 0x7ffc55b11230) = 0 > [root@nine ~]# clang --version > clang version 17.0.6 (Red Hat, Inc. 17.0.6-5.el9) > Target: x86_64-redhat-linux-gnu > Thread model: posix > InstalledDir: /usr/bin > [root@nine ~]# > > - Arnaldo