From patchwork Fri Jun 2 13:50:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 13265352 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31410C77B7A for ; Fri, 2 Jun 2023 13:52:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232213AbjFBNwA (ORCPT ); Fri, 2 Jun 2023 09:52:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235912AbjFBNv7 (ORCPT ); Fri, 2 Jun 2023 09:51:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 640C31BB; Fri, 2 Jun 2023 06:51:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E609F650A4; Fri, 2 Jun 2023 13:51:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 239A4C433D2; Fri, 2 Jun 2023 13:51:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1685713916; bh=8hDakrUZAZcYTZfGnQ3DNtCp7igSQOT1sESi2A5X7JQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iftz4zlbGT83MJweTTJpH3wQdggzYX6b+QAx9Koo1cv+16rmDoY0nvXO6m3xj06gj lFhzkTunQOpyko5GnC4nfOhIHj0SkwImYV4qStyONP6+MJKD0dulfUFetxSZe67aM7 OPzMQ8lUQagZ5mhexu5mPM8oUZ4Hw5WftHXsVwsRSapgjTRKvcG0sUatLogGT9Gndk GsEKI6E55mt4WjfPQBgknPAfxt6v2njHB9PZzPFQ1nhCz+KZYC939jBFpWEAJ2q3Ib W/rzdigetrW5OnLbh9inqnOBhVFXERpFmS/veBTt+MblQ1zwbPw7WBODQVTgySSLp4 LV91jautrX54g== From: Arnd Bergmann To: Yonghong Song , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Song Liu , Steven Rostedt , Masami Hiramatsu Cc: Arnd Bergmann , stable@vger.kernel.org, John Fastabend , Martin KaFai Lau , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Kumar Kartikeya Dwivedi , Dave Marchevsky , Delyan Kratunov , Joanne Koong , Peter Zijlstra , "Jason A. Donenfeld" , Roberto Sassu , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH 2/2] [v3] bpf: fix bpf_probe_read_kernel prototype mismatch Date: Fri, 2 Jun 2023 15:50:19 +0200 Message-Id: <20230602135128.1498362-2-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230602135128.1498362-1-arnd@kernel.org> References: <20230602135128.1498362-1-arnd@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org From: Arnd Bergmann bpf_probe_read_kernel() has a __weak definition in core.c and another definition with an incompatible prototype in kernel/trace/bpf_trace.c, when CONFIG_BPF_EVENTS is enabled. Since the two are incompatible, there cannot be a shared declaration in a header file, but the lack of a prototype causes a W=1 warning: kernel/bpf/core.c:1638:12: error: no previous prototype for 'bpf_probe_read_kernel' [-Werror=missing-prototypes] On 32-bit architectures, the local prototype u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) passes arguments in other registers as the one in bpf_trace.c BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size, const void *, unsafe_ptr) which uses 64-bit arguments in pairs of registers. Change the core.c file to only reference the inner bpf_probe_read_kernel_common() helper and provide a prototype for that, to ensure this is compatible with both definitions. Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann Acked-by: Yonghong Song --- v3: clarify changelog text further. v2: rewrite completely to fix the mismatch. --- include/linux/bpf.h | 2 ++ kernel/bpf/core.c | 9 ++++++--- kernel/trace/bpf_trace.c | 3 +-- 3 files changed, 9 insertions(+), 5 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f58895830adae..55826398acfba 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2619,6 +2619,8 @@ static inline void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr) } #endif /* CONFIG_BPF_SYSCALL */ +int bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr); + void __bpf_free_used_btfs(struct bpf_prog_aux *aux, struct btf_mod_pair *used_btfs, u32 len); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 0926714641eb5..565ef6950c7a8 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -1635,11 +1636,13 @@ bool bpf_opcode_in_insntable(u8 code) } #ifndef CONFIG_BPF_JIT_ALWAYS_ON -u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) +#ifndef CONFIG_BPF_EVENTS +int bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr) { memset(dst, 0, size); return -EFAULT; } +#endif /** * ___bpf_prog_run - run eBPF program on a given context @@ -1931,8 +1934,8 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ CONT; \ LDX_PROBE_MEM_##SIZEOP: \ - bpf_probe_read_kernel(&DST, sizeof(SIZE), \ - (const void *)(long) (SRC + insn->off)); \ + bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ + (const void *)(long) (SRC + insn->off)); \ DST = *((SIZE *)&DST); \ CONT; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 2bc41e6ac9fe0..290fdce2ce535 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -223,8 +223,7 @@ const struct bpf_func_proto bpf_probe_read_user_str_proto = { .arg3_type = ARG_ANYTHING, }; -static __always_inline int -bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr) +int bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr) { int ret;