From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-163.mta1.migadu.com [95.215.58.163]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 145D743D4FD for ; Wed, 30 Sep 2026 13:52:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.163 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790776344; cv=none; b=JOU4vVLQdTJAVk2CnQ0SjGueCAO/LJvY03FUBVb8h8gF5ZMRu+Z2Uox2MkTTl+CfMsxkCil86i3eaGFOjw+u6eWwOCXyBXVZAISJjsL4HIL12refAT6ypcP8lRFON9Wak2NGrpW5LIPvWytn2VzS6TAi/dQj7+C8QKM3ZjaImDc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790776344; c=relaxed/simple; bh=AfeltYVpXCk9FWs65H6joY5ChH2MtXhQYovBE0rEmzQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KYiqDRv/zLFZ+uqi62DrwONobbmOIGNPCUJwLIZ40w0uYWx4x3z6R2jNNxg9rgfyee93LutqjUw2SfaHBKbiKmgqze92owHM3D3xAAq3RpRZaKE4+IaBBvmPmkHkQRDucONdVHeg10QlZCMxzX1Da2c0dgRbRMfWGqfwUZTwV64= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ToJi3vCN; arc=none smtp.client-ip=95.215.58.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ToJi3vCN" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=AfeltYVpXCk9FWs65H6joY5ChH2MtXhQYovBE0rEmzQ=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790776331; v=1; x=1791381131; b=ToJi3vCNuUoCqHi+rcgwOKcRA5B1vsUqA8h2STaI5e5DE6l9wLK2frO6jnS4TCGEUk7gci0K pbqe7OP4yoIh8801/1VLNTlvFLbjqsSanby6CiXr7FmLTnyqlyVCmoyg7lHFELrzTNr7hlzz9et YVZWAwql9Y/byP+4lSAdBUPw= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id d603edd5d970b7f4; Wed, 30 Sep 2026 13:52:10 +0000 X-Mizu-Trace-ID: d603edd5d970b7f4 X-Migadu-Flow: FLOW_OUT From: Shakeel Butt To: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko Cc: Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Amery Hung , Tejun Heo , Meta kernel team , cgroups@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Yafang Shao Subject: [PATCH] bpf, cgroup: fix cgroup struct_ops query for a second attach type Date: Wed, 30 Sep 2026 06:51:59 -0700 Message-ID: <20260930135159.3926039-1-shakeel.butt@linux.dev> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Two things in __cgroup_bpf_query() work only because CGROUP_TCP_SOCK_OPS is the only one struct_ops attach type. It calls cgroup_bpf_enabled(atype) with an atype that find_atype_by_struct_ops_id() works out at runtime. That macro is an asm goto and needs a constant. Today the compiler can see there is only one value; add a second type and the build breaks with "impossible constraint in 'asm'". Add cgroup_bpf_enabled_runtime(), which reads the key instead, and use it here. This is a syscall path, so the cost does not matter. And find_atype_by_struct_ops_id() matches on type_id alone. An attach type whose subsystem is not built keeps type_id 0, so a query for type 0 finds it and returns success with nothing instead of -ENOENT. Skip such slots. Fixes: 369d9dcd8fb8 ("bpf: Add infrastructure to support attaching struct_ops to cgroups") Signed-off-by: Shakeel Butt Acked-by: Yafang Shao --- include/linux/bpf-cgroup.h | 9 +++++++++ kernel/bpf/cgroup.c | 3 ++- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index 8a75a6cd7309..3b2c127d401d 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -76,6 +76,14 @@ to_cgroup_bpf_attach_type(enum bpf_attach_type attach_type) extern struct static_key_false cgroup_bpf_enabled_key[MAX_CGROUP_BPF_ATTACH_TYPE]; #define cgroup_bpf_enabled(atype) static_branch_unlikely(&cgroup_bpf_enabled_key[atype]) +/* + * Same test when @atype is not a constant. cgroup_bpf_enabled() uses + * static_branch_unlikely which creates jump-label site and requires statically + * selected key. Since key is selected dynamically, use static_key_enabled here + * and keep it off fast paths. + */ +#define cgroup_bpf_enabled_runtime(atype) \ + static_key_enabled(&cgroup_bpf_enabled_key[atype]) struct bpf_cgroup_storage_map; @@ -508,6 +516,7 @@ static inline int cgroup_bpf_struct_ops_attach(struct bpf_map *map, } #define cgroup_bpf_enabled(atype) (0) +#define cgroup_bpf_enabled_runtime(atype) (0) #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, uaddrlen, atype, t_ctx) ({ 0; }) #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, uaddrlen, atype) ({ 0; }) #define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (0) diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 2bbe77de89f0..4187f99ea025 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -45,6 +45,7 @@ static enum cgroup_bpf_attach_type find_atype_by_struct_ops_id(u32 type_id) for (atype = 0; atype < MAX_CGROUP_BPF_ATTACH_TYPE; atype++) { if (cgroup_bpf_is_struct_ops_atype(atype) && + cgroup_struct_ops[atype].type_id && cgroup_struct_ops[atype].type_id == type_id) return atype; } @@ -1448,7 +1449,7 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, return -ENOENT; from_atype = to_atype = atype; flags = 0; - if (!cgroup_bpf_enabled(atype)) + if (!cgroup_bpf_enabled_runtime(atype)) goto skip_count; } else if (type == BPF_LSM_CGROUP) { if (!effective_query && attr->query.prog_cnt && -- 2.53.0-Meta