From nobody Sun Oct 5 12:23:02 2025 Received: from out-181.mta1.migadu.com (out-181.mta1.migadu.com [95.215.58.181]) (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 8AFE2254873 for ; Mon, 4 Aug 2025 12:16:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754309819; cv=none; b=Q/brRlKjk9RSQ5Gj/vkrf/cDwdFjKXLGobIYdIQroy/87eUmM7HXN8JRCdF5o2ReEpFgA+yVJ1qqfslmdP8WzSpA2krt6OQcAZLlQjTLyeyJxHrtrIJ90XY4VL+E1zegHhqClGdtjpkrxcOTeCBT5ypKoqoseAzNaPOcqD7kneE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754309819; c=relaxed/simple; bh=+QbjGDEaHCUYMo3kIkI0nfYav4d+Fau99j5zD5gp8V4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Lkx6aSItTrPedTaRrq9iKE24inyArySpsgznPogVcVBizRQpJmGCcdZ6ZG8PnSh3NmOUm9Zdz1ies79/by2EUaj0U79e5POIqYNlhCZS52zhNT1xWjBG4lRCCvCiNvdEIs4i0KfJ862gIggu6JfzDghLizeNtOMkJgg3kjGi/hY= 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=bDYto4Y8; arc=none smtp.client-ip=95.215.58.181 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="bDYto4Y8" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1754309805; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=dsCCYJVf50voJUlyGqf8P6lX4sGjnQ9vneNNYICjjks=; b=bDYto4Y8g2xjYdtZVG3OTKbd3cmcOZypPFOvFyrXQXHxnFIJLmJI6J+RKHaiIHMnC00E5z vrYbHW7Mg4Bka9kugv7cj2t3GZQOtiYdsVFXpicPViR8i6limBYoXOcp80tE6F3bYUZaCn lNz+r1nJW7DNHzUggAtcjaRb1+gVDSw= From: Tao Chen To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, mattbobrowski@google.com, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Tao Chen Subject: [PATCH bpf-next] bpf: Disable migrate when kprobe_multi attach to access bpf_prog_active Date: Mon, 4 Aug 2025 20:16:15 +0800 Message-ID: <20250804121615.1843956-1-chen.dylane@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" The syscall link_create not protected by bpf_disable_instrumentation, accessing percpu data bpf_prog_active should use cpu local_lock when kprobe_multi program attach. Fixes: 0dcac2725406 ("bpf: Add multi kprobe link") Signed-off-by: Tao Chen --- kernel/trace/bpf_trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 3ae52978cae..f6762552e8e 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2728,23 +2728,23 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_= link *link, struct pt_regs *regs; int err; =20 + migrate_disable(); if (unlikely(__this_cpu_inc_return(bpf_prog_active) !=3D 1)) { bpf_prog_inc_misses_counter(link->link.prog); err =3D 1; goto out; } =20 - migrate_disable(); rcu_read_lock(); regs =3D ftrace_partial_regs(fregs, bpf_kprobe_multi_pt_regs_ptr()); old_run_ctx =3D bpf_set_run_ctx(&run_ctx.session_ctx.run_ctx); err =3D bpf_prog_run(link->link.prog, regs); bpf_reset_run_ctx(old_run_ctx); rcu_read_unlock(); - migrate_enable(); =20 out: __this_cpu_dec(bpf_prog_active); + migrate_enable(); return err; } =20 --=20 2.48.1