From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f179.google.com (mail-pf1-f179.google.com [209.85.210.179]) (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 7336B1F4E48; Fri, 2 May 2025 20:16:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746216988; cv=none; b=krsQw5yzrrPlOHTMQqI6TpBlm2fjkwMk6+qSdQP9qWLZPeCVbJprvIVBLbG3RdPfmaXMedUSNnUa39yFJqjXUCH10LEYWGlta3tO1izu392OmCVwLQGwDBX8v8I1pgplFE8JScEJtavdnXMyuEethacqmbt+DHPmRwDD1D2gnuE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746216988; c=relaxed/simple; bh=mx3eC8ta534+w5IvQAC/RI6rZI9V0x99os2K5CgyPFo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PxG5+gYZm9SZTQrYlmh5S+6nGzom0orkXKQsBx6zDmmT5VcywxwstwsGM23hmSnwtBoX4jA7IvYHFV2nrnVPwbHZ4tGr+51aWJZLcV+g/HEJMOVJSrdDB86yqdw8/si9ASpdeQDv+G0sjDlgIq54msizmpKefIF/FsBcZdUnaOk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=KfD8cRtG; arc=none smtp.client-ip=209.85.210.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KfD8cRtG" Received: by mail-pf1-f179.google.com with SMTP id d2e1a72fcca58-736bfa487c3so2419363b3a.1; Fri, 02 May 2025 13:16:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1746216986; x=1746821786; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=LJc6UxIt2ePjgnBTAhbKzmmYXMNfTJKhg/U6k9Nru0w=; b=KfD8cRtGThvrbFeOqyKIyIr8O++C4T8byJqkrXHCk7SFwdXhu+WZUSzALO4IjtccRp oqMhREmZQBNGIyPcxaGfDd/T9E1TcRW5bjzh5JO6UQP0QJmXeuu047r0lJj+31WnkgEL CFHYkSnHH1vDGvCEiM9ikk1ONkTJ98w6BrnT7dXo1NSodt8/D6vKXgMbOX8qgMQz9TC4 cLP7EQKm2whfvbb9u6TK5WlTlG01SmeOo2drYZkihSQoHrZJmBx7CxJgxWjKNaA4KVmA fopW7SZf0cKId67XfzgZUqNO+fNKA0as9/xYkwRWFDcp9zhdHF7hEurZ+LeI/ZyJysJI icvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1746216986; x=1746821786; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=LJc6UxIt2ePjgnBTAhbKzmmYXMNfTJKhg/U6k9Nru0w=; b=BbqaaYjL6k/iyQltsUXW/4N7N6+OhFGMKG/Yy85enOOSFswxyJB3Izg0lwcARP1OhJ +8LMUgogbYTHeXdwtwBHPVxREpICBJufS/xm0LY/7Z58cohfIPTR9Hqkz00mc/dO7StT RPxPmshEuSzpwX+VezmJSW4hV4LfXugNimWR27egn6NBMyoESXs5nrEZhp7YScIYNYpE 30hZ/Pb9t1sRfPCY8kXPcBSzBJkH1wSsVDo4SZTW6taSFnprleE8DceiVUsuTExC+4bH Zn+hDf1scsBBjCAe73/IGcu9VfEVNW5bWFvdoQ9mt5Cfy7+AnPSWNWIwynv7Glpyiuqx s/0A== X-Gm-Message-State: AOJu0Yyz2+Khrq0WHIhAfdc9NoMetHoZy6qe8+pLRaelZmLBZATpr9th Ab/Kq5Vk62JvQZ5Y8+kkZ5gPs7i6u/y+2U9NIkt9w8ZggXGOF4rtusNnfA== X-Gm-Gg: ASbGncuCZMGLo8V0M7Y42YHTEqNxlUT5VYjZds7lx0L7bsHybmpPiR/DhAoREKcVPcT eSASZj9c4EuBJoEPlZ+ubB/iuCAYxbqo+zwORqPDRGy3GBRY1R61dXevARsQFejHZoVFkWaACm/ OvzDhdiCzg6UyOlFS6hYHa7qlGAhvIk4LtIv8ebgbrv8h7YVbGm/8toU1+ZxKU3E5ueaU8V9Lev mNdG9KA9KS+9h9Y7+SL/nhXoJPy65p+fQ01EEElhtO9RB4wulbzTrtH7Y1mrX/UVE4wQo9b43aO 3BN7aF0bV9UZmV8FV7mxVP0cOTWarLw= X-Google-Smtp-Source: AGHT+IG/30QrZfnspbMQ+s4/HBAOUNlMqyBtYEOzkH4IJyvbx+YPNn3wGq38cHtf60/OUA7LPQbyqA== X-Received: by 2002:a05:6a00:320c:b0:740:6468:4e9 with SMTP id d2e1a72fcca58-74064680667mr1449066b3a.17.1746216986455; Fri, 02 May 2025 13:16:26 -0700 (PDT) Received: from localhost ([2a03:2880:ff:7::]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-74059021e13sm2027600b3a.89.2025.05.02.13.16.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 May 2025 13:16:26 -0700 (PDT) From: Amery Hung To: bpf@vger.kernel.org Cc: netdev@vger.kernel.org, alexei.starovoitov@gmail.com, andrii@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org, xiyou.wangcong@gmail.com, kernel-team@meta.com Subject: [PATCH bpf-next/net v2 1/5] bpf: net_sched: Fix bpf qdisc init prologue when set as default qdisc Date: Fri, 2 May 2025 13:16:20 -0700 Message-ID: <20250502201624.3663079-2-ameryhung@gmail.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250502201624.3663079-1-ameryhung@gmail.com> References: <20250502201624.3663079-1-ameryhung@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Allow .init to proceed if qdisc_lookup() returns NULL as it only happens when called by qdisc_create_dflt() in mq/mqprio_init and the parent qdisc has not been added to qdisc_hash yet. In qdisc_create(), the caller, __tc_modify_qdisc(), would have made sure the parent qdisc already exist. In addition, call qdisc_watchdog_init() whether .init succeeds or not to prevent null-pointer dereference. In qdisc_create() and qdisc_create_dflt(), if .init fails, .destroy will be called. As a result, the destroy epilogue could call qdisc_watchdog_cancel() with an uninitialized timer, causing null-pointer deference in hrtimer_cancel(). Fixes: c8240344956e ("bpf: net_sched: Support implementation of Qdisc_ops in bpf") Signed-off-by: Amery Hung --- net/sched/bpf_qdisc.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/sched/bpf_qdisc.c b/net/sched/bpf_qdisc.c index 9f32b305636f..a8efc3ff2b7e 100644 --- a/net/sched/bpf_qdisc.c +++ b/net/sched/bpf_qdisc.c @@ -234,18 +234,20 @@ __bpf_kfunc int bpf_qdisc_init_prologue(struct Qdisc *sch, struct net_device *dev = qdisc_dev(sch); struct Qdisc *p; + qdisc_watchdog_init(&q->watchdog, sch); + if (sch->parent != TC_H_ROOT) { + /* If qdisc_lookup() returns NULL, it means .init is called by + * qdisc_create_dflt() in mq/mqprio_init and the parent qdisc + * has not been added to qdisc_hash yet. + */ p = qdisc_lookup(dev, TC_H_MAJ(sch->parent)); - if (!p) - return -ENOENT; - - if (!(p->flags & TCQ_F_MQROOT)) { + if (p && !(p->flags & TCQ_F_MQROOT)) { NL_SET_ERR_MSG(extack, "BPF qdisc only supported on root or mq"); return -EINVAL; } } - qdisc_watchdog_init(&q->watchdog, sch); return 0; } -- 2.47.1