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 48C022E64A; Thu, 14 Nov 2024 17:57:05 +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=1731607026; cv=none; b=V66rL1A6bKBqDO9C1VlWGRyyJPRFOXe1igg1lVoFLfCkm+sU4HNwhH/lnrJAB2lRc9f4nuj08M8+uVlNRqHFFprSAzI66fsed5AP7uUlqoXWK1RMSWJjgVjohtaIVCsTMG9a5/2x2TH2y/AeFB6gKrschljyv/kilyknP3B13ic= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731607026; c=relaxed/simple; bh=sVAV1WUFBQUvV6qnzb1SsvFG/Zw9vowxBGsBBChgEsg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fIBVFnEsmFk88Fdvou3QLlGcy/Zy1jE/eO15xd9uEiwoKEwZVUWkVRwfVQ04SGf1SmV4h5YXPQyj0tiPbXqt5vRst3z5oIJ83536oIYWb3ZnNHR6LALm3BsEcklVt0QKjUxHt8D8cKDDbyonehOdRz1d/eO4yuTCguVySCNZARA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nFkU2QCU; 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="nFkU2QCU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DC1EC4CECD; Thu, 14 Nov 2024 17:57:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731607025; bh=sVAV1WUFBQUvV6qnzb1SsvFG/Zw9vowxBGsBBChgEsg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nFkU2QCUUtTErZlXihmA+u1S31hRPQS9DkRwAdV+S7wITRybN2cw19uUGnfy2ovaw 11d06sdoi2C6A4aqWWZCOa71qAul1YL7afGa8+l4HKH9XREqf7p5dGK7c7HejhOeXM h3YJKf3mHY7++ExAi9L6nSP5xzwLCUdiUBkjIsD20kn1DnYlqUiplIBLtOxGhlir5E L/vElX1l4PHESGMOuLlh6QqyvDJeehR0xZn4TjNKQIxpuMYNIdwa4TPNTtzNGUwFf3 em/1zD6y+8wB5uKQuP1mA/tKeeYy9/QC+tg9AzDlClNe+bfUFPojHRtThhLpL3Xx5/ Sf/NiwTGWJDZg== Date: Thu, 14 Nov 2024 14:57:02 -0300 From: Arnaldo Carvalho de Melo To: Howard Chu Cc: peterz@infradead.org, namhyung@kernel.org, irogers@google.com, mingo@redhat.com, mark.rutland@arm.com, james.clark@linaro.org, alexander.shishkin@linux.intel.com, jolsa@kernel.org, adrian.hunter@intel.com, kan.liang@linux.intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] perf trace: Fix perf trace tracing itself, creating feedback loops Message-ID: References: <20241030052431.2220130-1-howardchu95@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@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: On Tue, Nov 12, 2024 at 02:07:36PM -0300, Arnaldo Carvalho de Melo wrote: > On Tue, Oct 29, 2024 at 10:24:31PM -0700, Howard Chu wrote: > > There exists a pids_filtered map in augmented_raw_syscalls.bpf.c that > > ceases to provide functionality after the BPF skeleton migration: > > commit 5e6da6be3082 ("perf trace: Migrate BPF augmentation to use a skeleton") > > Thanks, applied to perf-tools-next, There is a problem with this patch, I'm investigating it now: root@number:~# perf trace -e syscalls:sys_enter_exit_group true perf: Segmentation fault Obtained 12 stack frames. perf() [0x6229a1] perf() [0x622a8b] /lib64/libc.so.6(+0x40d00) [0x7f704364fd00] perf() [0x4b5f2e] perf() [0x4ba3e6] perf() [0x4c03bc] perf() [0x4c0663] perf() [0x4c07bc] perf() [0x4c0b05] /lib64/libc.so.6(+0x2a088) [0x7f7043639088] /lib64/libc.so.6(__libc_start_main+0x8b) [0x7f704363914b] perf() [0x412265] Segmentation fault (core dumped) root@number:~# (gdb) run trace -e syscalls:sys_enter_exit_group true Starting program: /root/bin/perf trace -e syscalls:sys_enter_exit_group true This GDB supports auto-downloading debuginfo from the following URLs: Enable debuginfod for this session? (y or [n]) y Debuginfod has been enabled. To make this setting permanent, add 'set debuginfod enabled on' to .gdbinit. [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". [Detaching after fork from child process 1965197] Program received signal SIGSEGV, Segmentation fault. trace__run (trace=0x7fffffffa5e0, argc=1, argv=0x7fffffffde90) at builtin-trace.c:4330 4330 trace->filter_pids.map = trace->skel->maps.pids_filtered; (gdb) bt #0 trace__run (trace=0x7fffffffa5e0, argc=1, argv=0x7fffffffde90) at builtin-trace.c:4330 #1 0x00000000004ba3e6 in cmd_trace (argc=1, argv=0x7fffffffde90) at builtin-trace.c:5490 #2 0x00000000004c03bc in run_builtin (p=0xec4068 , argc=4, argv=0x7fffffffde90) at perf.c:351 #3 0x00000000004c0663 in handle_internal_command (argc=4, argv=0x7fffffffde90) at perf.c:404 #4 0x00000000004c07bc in run_argv (argcp=0x7fffffffdc7c, argv=0x7fffffffdc70) at perf.c:448 #5 0x00000000004c0b05 in main (argc=4, argv=0x7fffffffde90) at perf.c:560 (gdb) p trace->skel $1 = (struct augmented_raw_syscalls_bpf *) 0x0 (gdb) I.e. when we specify a syscall event tracepoint, we expect to use augmentation, but are not setting it up. So this is seems to be exposing a previous bug, I'll check. - Arnaldo