From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.2]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 80D161A8F6D; Thu, 14 Aug 2025 06:45:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.2 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755153935; cv=none; b=jP84zm24JjGl3Te6KqpogfJ+GrP4pftgYuEeAwhbPQ1jqsZQ9G4pLn++w7k4iq7XELxsL5bGZKPkZ9Oo9qtAOXmqfjjVs4tJ4FrW4l4rDl0NhjzHXkiI9APQlJF8OTKvMcx6nyEk9k0oS7X61JeY0MEuFnr50WQwMJOjoIRRXLw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755153935; c=relaxed/simple; bh=YNja6IVSOY6sdmIEGLejUQMYR8hr8Qkd8soi9Q7EB60=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=uLDnGreZ80SMi1HV61eLSqvuCZp+sWauhn1rTa2CTofb8R1SjQDusV5ILptc3Wb88Sug7n4+Yvspxikr3bJhQmrrX5wT7WzsyHYSi3rzsqHAb+ACnTaehatAlIS74Y/pLOMV4D+f6oOqr8/PmTfBlHcrG0wJsul+Bbi8V/QL3fA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=Hx0l1JLy; arc=none smtp.client-ip=220.197.31.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="Hx0l1JLy" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=Xj br36XZUwrrEazXviwGyEwfOeujlfh38MalOHv4Awg=; b=Hx0l1JLy3dRQNxeAoq YS1XrQSRNBG2Y67W8hQ5YB1OpBPtTt++DnToXTskG98IUG6J6cSzA2WeuP4kJB8b 5RuS50BJWfaMA5YY4LvmJvUQbYQSn5RcRkYEzWju1YstvbeRbOMsD3QGFhWNH5zz frnZhqSAMAde79ROeWyBrdFws= Received: from phoenix.. (unknown []) by gzga-smtp-mtada-g0-2 (Coremail) with SMTP id _____wCHVEjxhZ1oTQ2nBQ--.36242S2; Thu, 14 Aug 2025 14:45:07 +0800 (CST) From: Jiawei Zhao To: andrii@kernel.org Cc: eddyz87@gmail.com, ast@kernel.org, daniel@iogearbox.net, shuah@kernel.org, yonghong.song@linux.dev, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v8 0/2] libbpf: fix USDT SIB argument handling causing unrecognized register error Date: Thu, 14 Aug 2025 06:45:02 +0000 Message-ID: <20250814064504.103401-1-phoenix500526@163.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wCHVEjxhZ1oTQ2nBQ--.36242S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxJrWxGr13ZF17Cw18Gry5CFg_yoW8KF4Dpa yrK3s8tryUta43JFsxXr47tr43Gan3Gr4UGFn2qw1Yvr4rGFyxJr4xKr15JrnxGa95Xa4Y vF1DtFs8Ga4rAwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jjtC7UUUUU= X-CM-SenderInfo: pskrv0dl0viiqvswqiywtou0bp/1tbiFAapiGidgJR9xwAAso When using GCC on x86-64 to compile an usdt prog with -O1 or higher optimization, the compiler will generate SIB addressing mode for global array and PC-relative addressing mode for global variable, e.g. "1@-96(%rbp,%rax,8)" and "-1@4+t1(%rip)". The current USDT implementation in libbpf cannot parse these two formats, causing `bpf_program__attach_usdt()` to fail with -ENOENT (unrecognized register). This patch series adds support for SIB addressing mode in USDT probes. The main changes include: - add correct handling logic for SIB-addressed arguments in `parse_usdt_arg`. - add an usdt_o2 test case to cover SIB addressing mode. Testing shows that the SIB probe correctly generates 8@(%rcx,%rax,8) argument spec and passes all validation checks. The modification history of this patch series: Change since v1: - refactor the code to make it more readable - modify the commit message to explain why and how Change since v2: - fix the `scale` uninitialized error Change since v3: - force -O2 optimization for usdt.test.o to generate SIB addressing usdt and pass all test cases. Change since v4: - split the patch into two parts, one for the fix and the other for the test Change since v5: - Only enable optimization for x86 architecture to generate SIB addressing usdt argument spec. Change since v6: - Add an usdt_o2 test case to cover SIB addressing mode. - Reinstate the usdt.c test case. Change since v7: - Refactor modifications to __bpf_usdt_arg_spec to avoid increasing its size, achieving better compatibility - Fix some minor code style issues - Refactor the usdt_o2 test case, removing semaphore and adding GCC attribute to force -O2 optimization Jiawei Zhao (2): libbpf: fix USDT SIB argument handling causing unrecognized register error selftests/bpf: Add an usdt_o2 test case in selftests to cover SIB handling logic tools/lib/bpf/usdt.bpf.h | 55 ++++++++++++++- tools/lib/bpf/usdt.c | 61 ++++++++++++++-- tools/testing/selftests/bpf/Makefile | 1 + .../selftests/bpf/prog_tests/usdt_o2.c | 69 +++++++++++++++++++ .../selftests/bpf/progs/test_usdt_o2.c | 37 ++++++++++ 5 files changed, 216 insertions(+), 7 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/usdt_o2.c create mode 100644 tools/testing/selftests/bpf/progs/test_usdt_o2.c -- 2.43.0