From mboxrd@z Thu Jan 1 00:00:00 1970 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 27E4EC4332F for ; Thu, 13 Oct 2022 00:55:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230202AbiJMAzP (ORCPT ); Wed, 12 Oct 2022 20:55:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232125AbiJMAyv (ORCPT ); Wed, 12 Oct 2022 20:54:51 -0400 Received: from out2.migadu.com (out2.migadu.com [IPv6:2001:41d0:2:aacc::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 867093FED2; Wed, 12 Oct 2022 17:51:48 -0700 (PDT) Message-ID: <1e01ab5a-c171-0b7a-751a-9ba7da4cd5dd@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1665622237; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=k/4PQl6S8K8YKQWiw/lI3bN5DKyscYp+FE64FP1WhMc=; b=vwmhvq8re7hbiOG4qBRSk4FXZM/nzGus4gj56imZuUUEOGAxRTzr7oem1Nr2XYucFaM8ws 9tblSdKkJ607zHYuoMz3/+F/LF5zj97zTGnXJS4b8/gu3zTke9pJcpEx3Hyq0nDR7WTSm/ xIu1wnErkWQRoNRpyICmTSuwHnEpFGM= Date: Wed, 12 Oct 2022 17:50:33 -0700 MIME-Version: 1.0 Subject: Re: [PATCH] bpf/btf: Fix is_int_ptr() Content-Language: en-US To: Chengming Zhou Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org References: <20221012125815.76120-1-zhouchengming@bytedance.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20221012125815.76120-1-zhouchengming@bytedance.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/12/22 5:58 AM, Chengming Zhou wrote: > When tracing a kernel function with arg type is u32*, btf_ctx_access() > would report error: arg2 type INT is not a struct. > > The commit bb6728d75611 ("bpf: Allow access to int pointer arguments > in tracing programs") added support for int pointer, but don't skip > modifiers before checking it's type. This patch fixes it. A selftest is needed. You can refer to the selftest added in the patch set [0] of the commit bb6728d75611. This belongs to bpf-next. Please tag it as bpf-next and also v2 in the next revision: Documentation/bpf/bpf_devel_QA.rst (Q: How do I indicate which tree....) [0]: https://lore.kernel.org/bpf/20211208193245.172141-2-jolsa@kernel.org/ > > Fixes: bb6728d75611 ("bpf: Allow access to int pointer arguments in tracing programs") > Signed-off-by: Chengming Zhou > --- > kernel/bpf/btf.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index eba603cec2c5..2b343c42ed10 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -5316,8 +5316,8 @@ static bool is_int_ptr(struct btf *btf, const struct btf_type *t) > /* t comes in already as a pointer */ > t = btf_type_by_id(btf, t->type); > > - /* allow const */ > - if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST) > + /* skip modifiers */ > + while (btf_type_is_modifier(t)) There is btf_type_skip_modifiers() that should be useful here. > t = btf_type_by_id(btf, t->type); > > return btf_type_is_int(t);