From patchwork Tue Nov 5 13:26:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13862953 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (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 CD41A70837 for ; Tue, 5 Nov 2024 13:26:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730813218; cv=none; b=rpf8JTrTllrPgoULgqfSFk4W6umZR2BWsAtwV6SWN5LUW3XjPQCGbZmWiYabR9XL5mLFFZ5WDaCaHOuKFG/MFdNRYHEtYKDk3bzLyarNDDfLnSTP5a/yi0UMQcwI1/kKSub7Zv126TgBZDbRNTNicQZ/QKG3fGaUAZMJGvQ1Fo0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730813218; c=relaxed/simple; bh=dh42vq0Cqb+ZCOSgDX/8+8FJHtfSFQtLCLjqr00gu3U=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=OCIAHNorUpVLd+depX6gCWJQ7LLaT4ynCR9kgVFjNjzhRyAbOpF6Rpphum91LtcP+24wrZirimWQg4mXAgC7dRzzMhhSwU6Q+7zkvDNTzhIKVVmDmqHjIpDJqfVN1Z6lyH5X/GzJiUzJ4Ze0d2PHPM3R2UD8olEuqZkcQPtjC/0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=bAwH+6IK; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bAwH+6IK" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-e30daaf5928so10334713276.1 for ; Tue, 05 Nov 2024 05:26:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1730813216; x=1731418016; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=t1pjRe8Y5dIIiOTSGCw6G493FCJZ/doxtEwp07yFy8k=; b=bAwH+6IKM7zBu8+lHKFalM77n8n/caQ9LUdnI0nLB3D7WjhZSsPSCBkaLd0sEWjmC0 Rs7o6teYvLeHhQkYPL5i3OG7jZyNY9B/k1AtJ9S4rTngjmFY2pdSHQ5609pOL+BI+MDM Ot02YrlDfH44ywc/Y+VeXn4YLPKpfjCMscmQy9winUv98rFSCc+2rW8f7Mh9YF8uBm4h 6rRLBCJZIR422FQXj0SALAC4zlHzKHY2SGUISPKpmn19O3q3QZLlEbuZ4JhQwVgQc3GX odLSSxUExWdkSImMnra8UkD7Mc7BxxwTuuWUBfN8x7z2qzTyege5d3BhjV36nkZrFnB2 wHwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730813216; x=1731418016; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=t1pjRe8Y5dIIiOTSGCw6G493FCJZ/doxtEwp07yFy8k=; b=UPGijf83fXriX0YH9/QGg2hXFdpRV9stSY4maqJEU24ytHlz6Dr4uUszNp7oC5ttcE xDImWv0I1tUqCCzxaDGJEJPonuWYXEDJgnbQ9itb9BZsywUz7bE1D1Um6ysQLATrqFt1 F9JrnHJlxzd4c8FgpXSpo6tmVYZWqj4sthL84p6+xO9hgN8/0kXJG9jQjIaSNJpZKw3d SqD96GXr9wxWTUecsXO95CDl3rLFcTSrVXaiEPRbotYEznksiOrlAvHwLaGiXm8H8P4x Z3g6BwAec5E4TcJb4VkEpxgD3zR7fxYz+xuJ07AvoMTmrBzN/hDOhBC/k3zGu2TApPoG 6m1A== X-Gm-Message-State: AOJu0YxzBD1ODCT62KMv4/jNYale0XHsspamKkpyO6gwuNzEjkN0on03 RnjqdbcdPH8hArnZwc0vMaHBGS+zu7Nq9ODHnXM6jOZr5UuNe1fnzH5UcGbV3SRRV5l3hY50hIo OQx2Vq0hI8Q== X-Google-Smtp-Source: AGHT+IFpoGTOV55fTr9hY+EZRWHlntm06o2KKCwq9kgw2VKZclUzqPmMN+iApFgUVNoS/vWpIxUCD7wY15hSrw== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:f7:ea0b:ac12:11d6]) (user=edumazet job=sendgmr) by 2002:a25:a549:0:b0:e30:c6ce:1165 with SMTP id 3f1490d57ef6-e30c6ce1d94mr47121276.1.1730813215738; Tue, 05 Nov 2024 05:26:55 -0800 (PST) Date: Tue, 5 Nov 2024 13:26:45 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.47.0.199.ga7371fff76-goog Message-ID: <20241105132645.654244-1-edumazet@google.com> Subject: [PATCH v2 net] phonet: do not call synchronize_rcu() from phonet_route_del() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet , syzbot , Kuniyuki Iwashima , Remi Denis-Courmont X-Patchwork-Delegate: kuba@kernel.org Calling synchronize_rcu() while holding rcu_read_lock() is not permitted [1] Move the synchronize_rcu() + dev_put() to route_doit(). Alternative would be to not use rcu_read_lock() in route_doit(). [1] WARNING: suspicious RCU usage 6.12.0-rc5-syzkaller-01056-gf07a6e6ceb05 #0 Not tainted ----------------------------- kernel/rcu/tree.c:4092 Illegal synchronize_rcu() in RCU read-side critical section! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by syz-executor427/5840: #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: route_doit+0x3d6/0x640 net/phonet/pn_netlink.c:264 stack backtrace: CPU: 1 UID: 0 PID: 5840 Comm: syz-executor427 Not tainted 6.12.0-rc5-syzkaller-01056-gf07a6e6ceb05 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 lockdep_rcu_suspicious+0x226/0x340 kernel/locking/lockdep.c:6821 synchronize_rcu+0xea/0x360 kernel/rcu/tree.c:4089 phonet_route_del+0xc6/0x140 net/phonet/pn_dev.c:409 route_doit+0x514/0x640 net/phonet/pn_netlink.c:275 rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6790 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2551 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:744 sock_write_iter+0x2d7/0x3f0 net/socket.c:1165 new_sync_write fs/read_write.c:590 [inline] vfs_write+0xaeb/0xd30 fs/read_write.c:683 ksys_write+0x183/0x2b0 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 17a1ac0018ae ("phonet: Don't hold RTNL for route_doit().") Reported-by: syzbot Signed-off-by: Eric Dumazet Cc: Kuniyuki Iwashima Cc: Remi Denis-Courmont Reviewed-by: Kuniyuki Iwashima --- v2: also move dev_put() to keep it after synchronize_rcu() net/phonet/pn_dev.c | 5 +++-- net/phonet/pn_netlink.c | 12 ++++++++++-- 2 files changed, 13 insertions(+), 4 deletions(-) diff --git a/net/phonet/pn_dev.c b/net/phonet/pn_dev.c index 19234d664c4fb537eba0267266efbb226cf103c3..5c36bae37b8fa85d2e97bf11d099c6c8599dcc5f 100644 --- a/net/phonet/pn_dev.c +++ b/net/phonet/pn_dev.c @@ -406,8 +406,9 @@ int phonet_route_del(struct net_device *dev, u8 daddr) if (!dev) return -ENOENT; - synchronize_rcu(); - dev_put(dev); + + /* Note : our caller must call synchronize_rcu() and dev_put(dev) */ + return 0; } diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c index ca1f04e4a2d9eb3b2a6d6cc5b299aee28d569b08..b9043c92dc246f8c5c313b262eb3ec4afad47ecb 100644 --- a/net/phonet/pn_netlink.c +++ b/net/phonet/pn_netlink.c @@ -233,6 +233,7 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh, { struct net *net = sock_net(skb->sk); struct nlattr *tb[RTA_MAX+1]; + bool sync_needed = false; struct net_device *dev; struct rtmsg *rtm; u32 ifindex; @@ -269,13 +270,20 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh, return -ENODEV; } - if (nlh->nlmsg_type == RTM_NEWROUTE) + if (nlh->nlmsg_type == RTM_NEWROUTE) { err = phonet_route_add(dev, dst); - else + } else { err = phonet_route_del(dev, dst); + if (!err) + sync_needed = true; + } rcu_read_unlock(); + if (sync_needed) { + synchronize_rcu(); + dev_put(dev); + } if (!err) rtm_phonet_notify(net, nlh->nlmsg_type, ifindex, dst);