From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from wfout2-smtp.messagingengine.com (wfout2-smtp.messagingengine.com [64.147.123.145]) (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 8DCFF29A2 for ; Tue, 30 Apr 2024 23:29:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=64.147.123.145 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714519777; cv=none; b=AkGl04v0VOm9n9F8/MZs69Lfk1vYMysImBZkM2c9R11JWlrpXsq71XcgrW2lGNSLqb4lIHCSgc4Ym9fWAHWsNQEgCIcnxLSVToHjILJP8MJKH3BzwfQ4Wdn6C7gookiMaqZkinVAKDCDA25OQD6XIF/3ex0CqKSg4KQY0ZzCNI4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714519777; c=relaxed/simple; bh=BaF1lZHFGScGucJHwZTz1NuGpMZOt8jXBP/CO9pfG1U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LHgOqXachfs3SiZMWv5Xf1l9zjnuEpHJ0JMDHXrLxbj749lDv+2yGSFryN0oOmcf29dnmPv7aIdDgfaRtI5PBJQcXOfphlSDaObfjdVk6k5+dqKx0XbYwGfLmoS20/aWXQCgdZrHg7JFl5QP+P8+m/iXdyaFEoogdLvBbReMfvQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dxuuu.xyz; spf=pass smtp.mailfrom=dxuuu.xyz; dkim=pass (2048-bit key) header.d=dxuuu.xyz header.i=@dxuuu.xyz header.b=ATYNk794; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=CgV7s0av; arc=none smtp.client-ip=64.147.123.145 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dxuuu.xyz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=dxuuu.xyz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=dxuuu.xyz header.i=@dxuuu.xyz header.b="ATYNk794"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="CgV7s0av" Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailfout.west.internal (Postfix) with ESMTP id E7EED1C00146; Tue, 30 Apr 2024 19:29:33 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Tue, 30 Apr 2024 19:29:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dxuuu.xyz; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:subject :subject:to:to; s=fm2; t=1714519773; x=1714606173; bh=aq+6FSPs+h vKLMIWDYssIribjWWIG+u0C0st8Ozi3BM=; b=ATYNk794WgjOhPLD9NXD7Y+KnF JIIIgjYgIUZsaeYLhgcRQoDO89L5zZqH4zxh/i+Sc6k5TeNA46HmHPVar8pjbwiD qi1HPD3/GMP+yyaBGno3khof8MjIg2LWfo3qCGHLVyfgzZa3z2yhzM7zOVWV2a8X zU/BkgBZiMx+pABZU0fkVMDrrQAWvVix9me9UoInjAQMjEU2eH7c8dorFrtm9y6I 97oKfj+sJd1x8yx6un5bLz34E29NW7fo6mnZ9PWk8Ei2YZx+jJXutK8r+5bQon2l dMCNziqGMXuoQq69JqQ8eTk8o10hYugSLSxaqjkAjFAVPqs25vOBYnNhOIJQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm3; t=1714519773; x=1714606173; bh=aq+6FSPs+hvKLMIWDYssIribjWWI G+u0C0st8Ozi3BM=; b=CgV7s0avL/X7J+RDUZgyUqN0iYIc+h27hpgTtu9hcwbb g/75z45rRYaoO9YEEyzEWoqHrN6lsQ2OrbZCluWBb4d6Qy95xa1p95IM6nSC4MrY 18ut4bB7OZIFNlnf28NhKQ7Lp9xAr7i8F6uY5MIoFtsseAMYUo8JaORKFlEvH3fy 7HqnsR/MNQ6tNlRUdjcNS+PxAdKzPAw7UlGz2wOaN3ahLaB/kiMFUrOwPBCADHT7 uKgDBwSrtz4RMd6xwPgVCUnuzUqI+f/C7V0glTn5vq4njn4WsI6qny6U7JJ/XCcq ISXrjmYUrRHRA/EVsZ1/VQAz1PEHA4XDCCc0NR5S/Q== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvledrvddugedgvddvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucgfrhhlucfvnfffucdlvdefmdenucfjughrpeffhf fvvefukfhfgggtuggjsehttdfstddttddvnecuhfhrohhmpeffrghnihgvlhcuighuuceo ugiguhesugiguhhuuhdrgiihiieqnecuggftrfgrthhtvghrnhepvdefkeetuddufeeige dtheefffekuedukeehudffudfffffggeeitdetgfdvhfdvnecuvehluhhsthgvrhfuihii vgeptdenucfrrghrrghmpehmrghilhhfrhhomhepugiguhesugiguhhuuhdrgiihii X-ME-Proxy: Feedback-ID: i6a694271:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 30 Apr 2024 19:29:32 -0400 (EDT) Date: Tue, 30 Apr 2024 17:29:31 -0600 From: Daniel Xu To: Arnaldo Carvalho de Melo Cc: jolsa@kernel.org, quentin@isovalent.com, alan.maguire@oracle.com, eddyz87@gmail.com, andrii.nakryiko@gmail.com, ast@kernel.org, daniel@iogearbox.net, bpf@vger.kernel.org Subject: Re: [PATCH dwarves v9 3/3] pahole: Inject kfunc decl tags into BTF Message-ID: References: <26ec519a00aa47f25bc6b4c7e4e15e5191ba4d45.1714430735.git.dxu@dxuuu.xyz> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 30, 2024 at 04:57:26PM GMT, Arnaldo Carvalho de Melo wrote: > On Mon, Apr 29, 2024 at 04:46:00PM -0600, Daniel Xu wrote: > > This commit teaches pahole to parse symbols in .BTF_ids section in > > vmlinux and discover exported kfuncs. Pahole then takes the list of > > kfuncs and injects a BTF_KIND_DECL_TAG for each kfunc. > > > > Example of encoding: > > > > $ bpftool btf dump file .tmp_vmlinux.btf | rg "DECL_TAG 'bpf_kfunc'" | wc -l > > 121 > > > > $ bpftool btf dump file .tmp_vmlinux.btf | rg 56337 > > [56337] FUNC 'bpf_ct_change_timeout' type_id=56336 linkage=static > > [127861] DECL_TAG 'bpf_kfunc' type_id=56337 component_idx=-1 > > > > This enables downstream users and tools to dynamically discover which > > kfuncs are available on a system by parsing vmlinux or module BTF, both > > available in /sys/kernel/btf. > > > > This feature is enabled with --btf_features=decl_tag,decl_tag_kfuncs. > > > > Acked-by: Jiri Olsa > > Tested-by: Jiri Olsa > > Reviewed-by: Alan Maguire > > Tested-by: Alan Maguire > > Signed-off-by: Daniel Xu > > Here I needed this to avoid an strdup possibly followed by a free and > then checking the strdup result, please Ack/revalidate tags. I'm > dropping them as there are changes. > > - Arnaldo > > diff --git a/btf_encoder.c b/btf_encoder.c > index e9d82e0af0e178fd..c2df2bc7a374447b 100644 > --- a/btf_encoder.c > +++ b/btf_encoder.c > @@ -1434,11 +1434,13 @@ static char *get_func_name(const char *sym) > return NULL; > > /* Strip prefix and handle malformed input such as __BTF_ID__func___ */ > - func = strdup(sym + sizeof(BTF_ID_FUNC_PFX) - 1); > - if (!strstr(func, "__")) { > - free(func); > + const char *func_sans_prefix = sym + sizeof(BTF_ID_FUNC_PFX) - 1; > + if (!strstr(func_sans_prefix, "__")) > return NULL; > - } > + > + func = strdup(func_sans_prefix); > + if (!func) > + return NULL; > > /* Strip suffix */ > end = strrchr(func, '_'); Thanks, that looks good to me. Please lemme know if I should re-spin. Otherwise, Acked-by: Daniel Xu