From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from todd.t-8ch.de (todd.t-8ch.de [159.69.126.157]) (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 D09A81DE8AA; Thu, 12 Dec 2024 23:37:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.69.126.157 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734046669; cv=none; b=en870kJJ3SYwhHzOGGIpaIORQ5uywMgOTwgILzwaQthDzfkp7GnhrNz3lCSbBPG1wRWXlg8qKmAFCykJNG1LKADmeK82BwR7s9rP/KSr9Rd1juveem9cWwaD3im8FtBJLFHMSbZ8f9GC7ecgnj+jMrHaGHDV65r8HeXWe4gC/3c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734046669; c=relaxed/simple; bh=YTgEMDc0ikMsMdmEEB/QR41m3JqAvO/1aSO2jbjFmKU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ip0wTG4t4/GUBNapKTd8a9w2psaphWk9hm4zsLaXE2VDekT7KK3BAmlKO0aCfkmqS/7mB/QBl04IoBZ7deoXABp6xKi96xM54gAPn/EhFnqFc654P/eBxMe6qHWF0HrmLDPRSkZn9bXlwh4I1YCV96HkakXPpUTUnxPr8eifw7c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net; spf=pass smtp.mailfrom=weissschuh.net; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b=VWg9PaCn; arc=none smtp.client-ip=159.69.126.157 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b="VWg9PaCn" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1734046664; bh=YTgEMDc0ikMsMdmEEB/QR41m3JqAvO/1aSO2jbjFmKU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VWg9PaCnY4j0AOXd7bHrJi6VU59uMT+B1hkIr46eoGwwJSzXHsesuaIzQnH+6zqRZ l7JhpsEBSppDLM7lugrv9FpVAFJ16V7+dHMIuxPnskyGYUoulc0eE9LyatIiRyUfhc HkDSHsyZPfy8fkG+39skJUHnXurVfOQc1GitlGGI= Date: Fri, 13 Dec 2024 00:37:44 +0100 From: Thomas =?utf-8?Q?Wei=C3=9Fschuh?= To: Andrii Nakryiko Cc: 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 , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH bpf] bpf: fix configuration-dependent BTF function references Message-ID: References: <20241213-bpf-cond-ids-v1-1-881849997219@weissschuh.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On 2024-12-12 15:27:12-0800, Andrii Nakryiko wrote: > On Thu, Dec 12, 2024 at 3:00 PM Thomas Weißschuh wrote: > > > > These BTF functions are not available unconditionally, > > only reference them when they are available. > > > > Avoid the following build warnings: > > > > BTF .tmp_vmlinux1.btf.o > > btf_encoder__tag_kfunc: failed to find kfunc 'bpf_send_signal_task' in BTF > > btf_encoder__tag_kfuncs: failed to tag kfunc 'bpf_send_signal_task' > > NM .tmp_vmlinux1.syms > > KSYMS .tmp_vmlinux1.kallsyms.S > > AS .tmp_vmlinux1.kallsyms.o > > LD .tmp_vmlinux2 > > NM .tmp_vmlinux2.syms > > KSYMS .tmp_vmlinux2.kallsyms.S > > AS .tmp_vmlinux2.kallsyms.o > > LD vmlinux > > BTFIDS vmlinux > > WARN: resolve_btfids: unresolved symbol prog_test_ref_kfunc > > WARN: resolve_btfids: unresolved symbol bpf_crypto_ctx > > WARN: resolve_btfids: unresolved symbol bpf_send_signal_task > > WARN: resolve_btfids: unresolved symbol bpf_modify_return_test_tp > > WARN: resolve_btfids: unresolved symbol bpf_dynptr_from_xdp > > WARN: resolve_btfids: unresolved symbol bpf_dynptr_from_skb > > > > Signed-off-by: Thomas Weißschuh > > --- > > kernel/bpf/helpers.c | 4 ++++ > > kernel/bpf/verifier.c | 8 ++++++++ > > 2 files changed, 12 insertions(+) > > > > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > > index 751c150f9e1cd7f56e6a2b68a7ebb4ae89a30d2d..5edf5436a7804816b7dcf1bbef2624d71a985f20 100644 > > --- a/kernel/bpf/helpers.c > > +++ b/kernel/bpf/helpers.c > > @@ -3089,7 +3089,9 @@ BTF_ID_FLAGS(func, bpf_task_get_cgroup1, KF_ACQUIRE | KF_RCU | KF_RET_NULL) > > BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL) > > BTF_ID_FLAGS(func, bpf_task_from_vpid, KF_ACQUIRE | KF_RET_NULL) > > BTF_ID_FLAGS(func, bpf_throw) > > +#ifdef CONFIG_BPF_EVENTS > > BTF_ID_FLAGS(func, bpf_send_signal_task, KF_TRUSTED_ARGS) > > +#endif > > BTF_KFUNCS_END(generic_btf_ids) > > > > static const struct btf_kfunc_id_set generic_kfunc_set = { > > @@ -3135,7 +3137,9 @@ BTF_ID_FLAGS(func, bpf_dynptr_is_null) > > BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) > > BTF_ID_FLAGS(func, bpf_dynptr_size) > > BTF_ID_FLAGS(func, bpf_dynptr_clone) > > +#ifdef CONFIG_NET > > BTF_ID_FLAGS(func, bpf_modify_return_test_tp) > > +#endif > > It makes little sense to have bpf_prog_test_run_tracing() and > bpf_modify_return_test_tp() depend on CONFIG_NET... It's just > historically where BPF_PROG_TEST_RUN functionality was implemented, > but it seems like we need to move bpf_prog_test_run_tracing() and > other tracing-related testing stuff into kernel/trace/bpf_trace.c or > somewhere under kernel/bpf/ (core.c? helpers.c?) I agree. But today these are the config values which are in effect. When the functions get moved, the config values can be adapted. With my commit "kbuild/btf: Propagate CONFIG_WERROR to resolve_btfids" in bpf-next the warnings can actually become errors. So I'd propose to apply this fix to avoid issues in the near future and then do a proper move without any urgency. > > BTF_ID_FLAGS(func, bpf_wq_init) > > BTF_ID_FLAGS(func, bpf_wq_set_callback_impl) > > BTF_ID_FLAGS(func, bpf_wq_start) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > > index 5e541339b2f6d1870561033fd55cca7144db14bc..77bbf58418fee7533bce539c8e005d2342ee1a48 100644 > > --- a/kernel/bpf/verifier.c > > +++ b/kernel/bpf/verifier.c > > @@ -5526,7 +5526,9 @@ static bool in_rcu_cs(struct bpf_verifier_env *env) > > > > /* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */ > > BTF_SET_START(rcu_protected_types) > > +#ifdef CONFIG_NET > > BTF_ID(struct, prog_test_ref_kfunc) > > +#endif > > #ifdef CONFIG_CGROUPS > > BTF_ID(struct, cgroup) > > #endif > > @@ -5534,7 +5536,9 @@ BTF_ID(struct, cgroup) > > BTF_ID(struct, bpf_cpumask) > > #endif > > BTF_ID(struct, task_struct) > > +#ifdef CONFIG_CRYPTO > > BTF_ID(struct, bpf_crypto_ctx) > > +#endif > > BTF_SET_END(rcu_protected_types) > > > > static bool rcu_protected_object(const struct btf *btf, u32 btf_id) > > @@ -11529,8 +11533,10 @@ BTF_ID(func, bpf_rdonly_cast) > > BTF_ID(func, bpf_rbtree_remove) > > BTF_ID(func, bpf_rbtree_add_impl) > > BTF_ID(func, bpf_rbtree_first) > > +#ifdef CONFIG_NET > > BTF_ID(func, bpf_dynptr_from_skb) > > BTF_ID(func, bpf_dynptr_from_xdp) > > +#endif > > BTF_ID(func, bpf_dynptr_slice) > > BTF_ID(func, bpf_dynptr_slice_rdwr) > > BTF_ID(func, bpf_dynptr_clone) > > @@ -11558,8 +11564,10 @@ BTF_ID(func, bpf_rcu_read_unlock) > > BTF_ID(func, bpf_rbtree_remove) > > BTF_ID(func, bpf_rbtree_add_impl) > > BTF_ID(func, bpf_rbtree_first) > > +#ifdef CONFIG_NET > > BTF_ID(func, bpf_dynptr_from_skb) > > BTF_ID(func, bpf_dynptr_from_xdp) > > +#endif > > BTF_ID(func, bpf_dynptr_slice) > > BTF_ID(func, bpf_dynptr_slice_rdwr) > > BTF_ID(func, bpf_dynptr_clone) > > > > --- > > base-commit: 5d287a7de3c95b78946e71d17d15ec9c87fffe7f > > change-id: 20241212-bpf-cond-ids-9bfbc64dd77b > > > > Best regards, > > -- > > Thomas Weißschuh > >