From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail115-95.sinamail.sina.com.cn (mail115-95.sinamail.sina.com.cn [218.30.115.95]) (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 4F2181BF321 for ; Tue, 6 Aug 2024 10:51:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=218.30.115.95 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722941491; cv=none; b=ohmNTmV9cQddi4LIqQoZBsV46XmcWnH4nQcIgLE1Aoub4jVzxD/G+Vp11SkZjWT/NfXFNBLatH3FujTYp2E7+PjpbIN5BorVJfTxr9nFDfjtbOVXHKAyin73t0iYXmQqXLhA30QuZ2BjLns/OQfEUWv8ryjnLb9fMjAMJ5Pu5lY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722941491; c=relaxed/simple; bh=L6P0WM96BT2R/yUyebIyUQxfqH2zTRgeQYUDZbf/FVw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FM/FT6k0pbcw65XxxVmcxskC8UbPDLrlAiSCA41AO0wT1oNPVXrIFEvvT9btiZnu5Ywa78TnwBYcFy4jGkPF1psy6jigKut56tjpes4Pqcw/FOFYxdDvKL5muhLEZEKHG7z6awLQQiLIMEZYhcfF8QFQq33AoXCPBIVaTn+8neM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; arc=none smtp.client-ip=218.30.115.95 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([113.118.70.152]) by sina.com (10.185.250.23) with ESMTP id 66B2002200005C93; Tue, 6 Aug 2024 18:51:17 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 6483658913460 X-SMAIL-UIID: 9C35B8A56B804044962FFA33CC185E40-20240806-185117-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [can?] WARNING: refcount bug in j1939_xtp_rx_cts Date: Tue, 6 Aug 2024 18:51:06 +0800 Message-Id: <20240806105106.2667-1-hdanton@sina.com> In-Reply-To: <000000000000b5bde0061ef65fc8@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Mon, 05 Aug 2024 14:29:36 -0700 > syzbot found the following issue on: > > HEAD commit: 743ff02152bc ethtool: Don't check for NULL info in prepare.. > git tree: net-next > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=162bd19d980000 #syz test net-next 743ff02152bc --- x/net/can/j1939/transport.c +++ y/net/can/j1939/transport.c @@ -1505,6 +1505,7 @@ static struct j1939_session *j1939_sessi session->state = J1939_SESSION_NEW; skb_queue_head_init(&session->skb_queue); + skb_get(skb); skb_queue_tail(&session->skb_queue, skb); skcb = j1939_skb_to_cb(skb); --