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 X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB1C3C388F9 for ; Mon, 2 Nov 2020 22:57:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 70A2621D40 for ; Mon, 2 Nov 2020 22:57:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XliRkOae" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725829AbgKBW5N (ORCPT ); Mon, 2 Nov 2020 17:57:13 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:48836 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725833AbgKBW5M (ORCPT ); Mon, 2 Nov 2020 17:57:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604357831; 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: in-reply-to:in-reply-to:references:references; bh=xAfRhWimI1jHGTVmCKQhK61uXzAn1vDaUQsK5qSZb3s=; b=XliRkOaeBBHVBIgnnqPeKgtHMp16q736G5RNsa89ogEIhZBLfqc9/YQvJss3GJFUpySy3+ QJpKdvlR7MjPJa+WHrceGAWbM46ZMpiaQ+awsVijJw9z+UhNypvInB23RKPEMVWpNsZ7DU H7t+H6YZXDRlAjdo0wWxQliryPRyT90= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-572-2KIihxFDPW636vKdPMkKRg-1; Mon, 02 Nov 2020 17:57:08 -0500 X-MC-Unique: 2KIihxFDPW636vKdPMkKRg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A6454801F9A; Mon, 2 Nov 2020 22:57:06 +0000 (UTC) Received: from krava (unknown [10.40.192.162]) by smtp.corp.redhat.com (Postfix) with SMTP id 7160960CCC; Mon, 2 Nov 2020 22:56:59 +0000 (UTC) Date: Mon, 2 Nov 2020 23:56:58 +0100 From: Jiri Olsa To: Jiri Olsa Cc: Arnaldo Carvalho de Melo , dwarves@vger.kernel.org, bpf@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , Yonghong Song , Hao Luo , "Frank Ch. Eigler" , Mark Wielaard Subject: Re: [PATCH 2/2] btf_encoder: Change functions check due to broken dwarf Message-ID: <20201102225658.GD3597846@krava> References: <20201031223131.3398153-1-jolsa@kernel.org> <20201031223131.3398153-3-jolsa@kernel.org> <20201102215908.GC3597846@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201102215908.GC3597846@krava> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, Nov 02, 2020 at 10:59:08PM +0100, Jiri Olsa wrote: > On Sat, Oct 31, 2020 at 11:31:31PM +0100, Jiri Olsa wrote: > > We need to generate just single BTF instance for the > > function, while DWARF data contains multiple instances > > of DW_TAG_subprogram tag. > > > > Unfortunately we can no longer rely on DW_AT_declaration > > tag (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97060) > > > > Instead we apply following checks: > > - argument names are defined for the function > > - there's symbol and address defined for the function > > - function is generated only once > > > > Also because we want to follow kernel's ftrace traceable > > functions, this patchset is adding extra check that the > > function is one of the ftrace's functions. > > > > All ftrace functions addresses are stored in vmlinux > > binary within symbols: > > __start_mcount_loc > > __stop_mcount_loc > > hum, for some reason this does not pass through bpf internal > functions like bpf_iter_bpf_map.. I learned it hard way ;-) > will check so it gets filtered out because it's __init function I'll check if the fix below catches all internal functions, but I guess we should do something more robust jirka --- diff --git a/btf_encoder.c b/btf_encoder.c index 0a378aa92142..3cd94280c35b 100644 --- a/btf_encoder.c +++ b/btf_encoder.c @@ -143,7 +143,8 @@ static int filter_functions(struct btf_elf *btfe, struct mcount_symbols *ms) /* Do not enable .init section functions. */ if (init_filter && func->addr >= ms->init_begin && - func->addr < ms->init_end) + func->addr < ms->init_end && + strncmp("bpf_", func->name, 4)) continue; /* Make sure function is within mcount addresses. */