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 A79E6223311 for ; Wed, 6 Aug 2025 08:59:04 +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=1754470744; cv=none; b=RDwCY3md1mqgMYQT/4ys3k/dLhy6Keq3LdXWIvviA4dzUMcBuNjUcpw6Y1Op/hltVIy8LHGDqXtSfbZ+Dh3UIRDB6x/Yr8jGOto0KuENHXZ5eLRNYATrFgmOOhWwgoJRJs3PQHUBErDsGdQxBegqf+z/mpii6CMgAJ4rICuO1mo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754470744; c=relaxed/simple; bh=10qrAanjlAsWoS6hCKdjwmWBFvBUnnPigoiSTHtO55Q=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=IVrxXfErHFXthPGnv9X4EXjWFmOCUbUuDKHcXY6iVSzl9BdpDI8hqDNQD2gad2JAxaxHIrbQgKJOkkaeuzyHzRLdaloIAkYTfSAJw7EgCnHMbpwBCRLaO9z+SnmEshnmHxS2pz14A2qXBzxxR9PkLNzI7PX1fO0EXCcFJ6+gVg0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JeAxl+Oe; 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="JeAxl+Oe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2335C4CEE7; Wed, 6 Aug 2025 08:59:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754470744; bh=10qrAanjlAsWoS6hCKdjwmWBFvBUnnPigoiSTHtO55Q=; h=From:To:Subject:Date:From; b=JeAxl+Oe1qiZeueiHHw77Z3KsBQLZa03NGcilDpQQe6tomNqDAGl9Gmm1/ckaqhZS A6n0jr+7ykmmwDIwoB5xWzBxmsesuvrT1XrAOzYB9qbQ0S/j8Y9pQSWivwBD/T54JU TvgoJe4SLzDhicXKfhoSDRtuR/CnQbQJ5d+PfyrGz0SdGPnz0nSEZAFnxXHG9npc8O 1OACETnXHPZ4ghubTuXQlTjSnm6prVU0DJASA0IrQs3er85qy8FAUQLfhVWt/fANE5 TCZcXNCZeE1sF1/MUd7qiBMoX+m41zCiTQruohK3+mjn8HdyfKOMBnZGPjcEKPkQsW urRh11iCej60g== From: Puranjay Mohan To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Puranjay Mohan , Xu Kuohai , Catalin Marinas , Will Deacon , Kumar Kartikeya Dwivedi , bpf@vger.kernel.org Subject: [PATCH bpf-next 0/3] bpf: Report arena faults to BPF streams Date: Wed, 6 Aug 2025 08:58:33 +0000 Message-ID: <20250806085847.18633-1-puranjay@kernel.org> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This set adds the support of reporting page faults inside arena to BPF stderr stream. The reported address is the one that a user would expect to see if they pass it to bpf_printk(); Here is an example output from a stream and bpf_printk() ERROR: Arena WRITE access at unmapped address 0xdeaddead0000 CPU: 9 UID: 0 PID: 502 Comm: test_progs Call trace: bpf_stream_stage_dump_stack+0xc0/0x150 bpf_prog_report_arena_violation+0x98/0xf0 ex_handler_bpf+0x5c/0x78 fixup_exception+0xf8/0x160 __do_kernel_fault+0x40/0x188 do_bad_area+0x70/0x88 do_translation_fault+0x54/0x98 do_mem_abort+0x4c/0xa8 el1_abort+0x44/0x70 el1h_64_sync_handler+0x50/0x108 el1h_64_sync+0x6c/0x70 bpf_prog_a64a9778d31b8e88_stream_arena_write_fault+0x84/0xc8 *(page) = 1; @ stream.c:100 bpf_prog_test_run_syscall+0x100/0x328 __sys_bpf+0x508/0xb98 __arm64_sys_bpf+0x2c/0x48 invoke_syscall+0x50/0x120 el0_svc_common.constprop.0+0x48/0xf8 do_el0_svc+0x28/0x40 el0_svc+0x48/0xf8 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x198/0x1a0 Same address is seen by using bpf_printk(): 1389.078831: bpf_trace_printk: Read Address: 0xdeaddead0000 To make this possible, some extra metadata has to be passed to the bpf exception handler, so the bpf exception handling mechanism for both x86-64 and arm64 have been improved in this set. The streams selftest has been updated to also test this new feature. Puranjay Mohan (3): bpf: arm64: simplify exception table handling bpf: Report arena faults to BPF stderr selftests/bpf: Add tests for arena fault reporting arch/arm64/net/bpf_jit_comp.c | 56 ++++++++----- arch/x86/net/bpf_jit_comp.c | 80 ++++++++++++++++++- include/linux/bpf.h | 1 + kernel/bpf/arena.c | 20 +++++ .../testing/selftests/bpf/prog_tests/stream.c | 24 ++++++ tools/testing/selftests/bpf/progs/stream.c | 37 +++++++++ 6 files changed, 192 insertions(+), 26 deletions(-) -- 2.47.3