From nobody Thu Nov 28 13:42:41 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 765BE1C57AD for ; Tue, 1 Oct 2024 13:27:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727789242; cv=none; b=Of+CpwFHWlj0fRaTMjEsWnU1L5RcffaK3qiJZy0pQOiDCn18dbRPp0jOQIJzmUqEXFKlpHvOMv60HLItC0uMqKheGTju/LAKPjMoUXmk31SQu4cUhqH0Q46aj5ICs/MhpTwrFJNiyIxh1GEEdR0NE+EImAVINoHATRiObr/SXOU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727789242; c=relaxed/simple; bh=vs+8a8RBHdEbbPO140pEJLtA7dPw90dKDnxZhk3Dau4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YDXknv/GkYo2lqjLaUat6HGatkxvoEy935u37sPkIB2SIrWsgoI+eTZm1JkKlgLHBazlQfTmn+n3X4AvWKuNy0PSSDgpGMxpHxQnaylFxzSuKR2xiauFPFM1at/0YOAmBHyXWUhXYWz7X5un6KwsWQgdbT/WOVn3mwq/ncjDZsk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=UzWSvaPQ; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UzWSvaPQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727789239; 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: in-reply-to:in-reply-to:references:references; bh=JEqhIvaP79zPkuiYDFnhoiphOYDN3GkfqESEaY0OOX4=; b=UzWSvaPQmxTkGjOTwt/sFe0HVkcPWxNOudqeaFNp1JGRlPTA1Y1g2RHcKLhtWNvlx6whWt o2LB3oFgea3hmJff7v1cKiNRu9kepuIYwUKhUejLC8Mcy156rFa4Nw9x0WGXnBBQUnHHRj TJOtoTrwJTMYyfihRvZijIL6VqAkbF0= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-381-OlPc42_BPPKQTK-8u2HGvw-1; Tue, 01 Oct 2024 09:27:13 -0400 X-MC-Unique: OlPc42_BPPKQTK-8u2HGvw-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id ACA121944DC4; Tue, 1 Oct 2024 13:27:11 +0000 (UTC) Received: from warthog.procyon.org.uk.com (unknown [10.42.28.145]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id F0D113003DEC; Tue, 1 Oct 2024 13:27:08 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , Marc Dionne , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org, yuxuanzhe@outlook.com, Simon Horman Subject: [PATCH net 1/2] rxrpc: Fix a race between socket set up and I/O thread creation Date: Tue, 1 Oct 2024 14:26:58 +0100 Message-ID: <20241001132702.3122709-2-dhowells@redhat.com> In-Reply-To: <20241001132702.3122709-1-dhowells@redhat.com> References: <20241001132702.3122709-1-dhowells@redhat.com> 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-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" In rxrpc_open_socket(), it sets up the socket and then sets up the I/O thread that will handle it. This is a problem, however, as there's a gap between the two phases in which a packet may come into rxrpc_encap_rcv() from the UDP packet but we oops when trying to wake the not-yet created I/O thread. As a quick fix, just make rxrpc_encap_rcv() discard the packet if there's no I/O thread yet. A better, but more intrusive fix would perhaps be to rearrange things such that the socket creation is done by the I/O thread. Fixes: a275da62e8c1 ("rxrpc: Create a per-local endpoint receive queue and = I/O thread") Signed-off-by: David Howells cc: yuxuanzhe@outlook.com cc: Marc Dionne cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Simon Horman cc: linux-afs@lists.infradead.org cc: netdev@vger.kernel.org Reviewed-by: Eric Dumazet --- net/rxrpc/ar-internal.h | 2 +- net/rxrpc/io_thread.c | 10 ++++++++-- net/rxrpc/local_object.c | 2 +- 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 80d682f89b23..d0fd37bdcfe9 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -1056,7 +1056,7 @@ bool rxrpc_direct_abort(struct sk_buff *skb, enum rxr= pc_abort_reason why, int rxrpc_io_thread(void *data); static inline void rxrpc_wake_up_io_thread(struct rxrpc_local *local) { - wake_up_process(local->io_thread); + wake_up_process(READ_ONCE(local->io_thread)); } =20 static inline bool rxrpc_protocol_error(struct sk_buff *skb, enum rxrpc_ab= ort_reason why) diff --git a/net/rxrpc/io_thread.c b/net/rxrpc/io_thread.c index 0300baa9afcd..07c74c77d802 100644 --- a/net/rxrpc/io_thread.c +++ b/net/rxrpc/io_thread.c @@ -27,11 +27,17 @@ int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff= *skb) { struct sk_buff_head *rx_queue; struct rxrpc_local *local =3D rcu_dereference_sk_user_data(udp_sk); + struct task_struct *io_thread; =20 if (unlikely(!local)) { kfree_skb(skb); return 0; } + io_thread =3D READ_ONCE(local->io_thread); + if (!io_thread) { + kfree_skb(skb); + return 0; + } if (skb->tstamp =3D=3D 0) skb->tstamp =3D ktime_get_real(); =20 @@ -47,7 +53,7 @@ int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *= skb) #endif =20 skb_queue_tail(rx_queue, skb); - rxrpc_wake_up_io_thread(local); + wake_up_process(io_thread); return 0; } =20 @@ -565,7 +571,7 @@ int rxrpc_io_thread(void *data) __set_current_state(TASK_RUNNING); rxrpc_see_local(local, rxrpc_local_stop); rxrpc_destroy_local(local); - local->io_thread =3D NULL; + WRITE_ONCE(local->io_thread, NULL); rxrpc_see_local(local, rxrpc_local_stopped); return 0; } diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c index 504453c688d7..f9623ace2201 100644 --- a/net/rxrpc/local_object.c +++ b/net/rxrpc/local_object.c @@ -232,7 +232,7 @@ static int rxrpc_open_socket(struct rxrpc_local *local,= struct net *net) } =20 wait_for_completion(&local->io_thread_ready); - local->io_thread =3D io_thread; + WRITE_ONCE(local->io_thread, io_thread); _leave(" =3D 0"); return 0;