From patchwork Mon Nov 4 15:26:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13861526 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 CD4F61B6D14 for ; Mon, 4 Nov 2024 15:26:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730733988; cv=none; b=ROaSbtGBmcSU5zgn5ej+aSJeEiRttOlN4IUCqxv44doQAkttPX6DYbpfxFRH0kfF/wKE8I0BEnB58NRlgDFV1rXy53fFgd60T2+/TPUiQ98982Lyo6dAlVYL/mo3N7RNNPQSwkqtKy3Xj6ej46RNRCx502Wd2c/eS/DqdSsfY5o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730733988; c=relaxed/simple; bh=ajOWgRvQDGIFCdepcy+aB7Rg4hFqDUIwBw+wsNolWt0=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=qZ98scxENPu0YOpj/o6Ovc10sZ4H/HzynQdSDB+4MuPw0s0rLPWv4NmYOBq3ngLW4gfsUV0rifybvu0K9YseiCk/KHzahPjwIvU+pi0wdn6B5z7BE+v7aZolIAbbvX5tmrmd55lWRCueawIqTgpA+yJZd90h8dQZlaYshsis8A4= 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=E8IekvU/; arc=none smtp.client-ip=209.85.219.202 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="E8IekvU/" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-e29135d1d0cso7105381276.1 for ; Mon, 04 Nov 2024 07:26:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1730733984; x=1731338784; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=c2JQ9uIIEkClb4SWhkB1sYRCZyBlRVG/GX7SdltLJVo=; b=E8IekvU/9eL4CWbUr0F4wIGYUEbiQHmbQXZ5IUEGae9Bd0iR/rnZ3feVe1sD2ATp5T i79nJBBI6rdfvSgQFSMH1cmNkMlIkpFIt2Jk3eAtqGiiD9lkOhtWLt8c9uhZd7MBGzE6 SNQHLX/WzK3dAkIvjyb4SgxgjGLtNymhh0y3Gq7ae2vwJOnSFRfZqEsg41SajOYcIKys 9qvcLnl5z0BIERwzQGQXYbcwuwYHiXSeAEUFio4lnTidUYo1zRxgfK0691yOZ9augc77 WgNMo2KEOmIo1qyCCeNcdO8b3EkTV05ufgJeoqzOGNKh9fHEw+AV7DPWEUq4Qho9j67W 7Fuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730733985; x=1731338785; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=c2JQ9uIIEkClb4SWhkB1sYRCZyBlRVG/GX7SdltLJVo=; b=d0dKl43JBYb+ULkrCLa8T2Hyl3Db1wrmlwD2Icx4jEhEsuhNAzzJwJQe/iUxnIyua/ DF1blLEfcG+6xZgdY6FC2k/4dQ0FrYfk5G1FLYf2GwQT9v6e3BI/Hto0/Bo8Imix1kil pGpWLsefbeMRjCoVgki3kceX/NsUlOiJwhGEW1ij8fKSEfuKwDJsd2XAThh1F4MCtmow TQTHVbE12G/hPaSuNw0lNIatwyn24pQ8ZL2T8udh25tZBw0AO+B98GglrnzPV5WaOyWZ P5odmawDF+8fUjRSr43O8SWD2AMN4NZ9+dRZ0E8ZVvPaOsxH8AI+vNCotxoapWdFsNZA wKdw== X-Gm-Message-State: AOJu0YwgalltawLvyUIUK6rqgEgU6BTOE06y0UDGdvBTwKqk6/OOtnWv pO4bueHQwjaTFiVe5mkYXIvw20JqDmgJPYIiy6r8E4LBZM3bInm6uZ0d8nwYViMLrOFy75lYuE0 dsAj2SdRuYg== X-Google-Smtp-Source: AGHT+IFvUv8BJpNyZ89NZaPoPBgaKRZfX/w9AO30D11PSrQb90dvQ9wWW7Humf338UVAWPnSYK8iCr7W0Skbug== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:f7:ea0b:ac12:11d6]) (user=edumazet job=sendgmr) by 2002:a25:83c7:0:b0:e20:2502:be14 with SMTP id 3f1490d57ef6-e330356f9camr7941276.7.1730733984389; Mon, 04 Nov 2024 07:26:24 -0800 (PST) Date: Mon, 4 Nov 2024 15:26:22 +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 2.47.0.163.g1226f6d8fa-goog Message-ID: <20241104152622.3580037-1-edumazet@google.com> Subject: [PATCH net-next] 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() to 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 --- net/phonet/pn_dev.c | 4 +++- net/phonet/pn_netlink.c | 10 ++++++++-- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/net/phonet/pn_dev.c b/net/phonet/pn_dev.c index 19234d664c4fb537eba0267266efbb226cf103c3..578d935f2b11694fd1004c5f854ec344b846eeb2 100644 --- a/net/phonet/pn_dev.c +++ b/net/phonet/pn_dev.c @@ -406,7 +406,9 @@ int phonet_route_del(struct net_device *dev, u8 daddr) if (!dev) return -ENOENT; - synchronize_rcu(); + + /* Note : our caller must call synchronize_rcu() */ + dev_put(dev); return 0; } diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c index ca1f04e4a2d9eb3b2a6d6cc5b299aee28d569b08..24930733ac572ed3ec5fd142d347c115346a28fa 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; @@ -269,16 +270,21 @@ 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 (!err) rtm_phonet_notify(net, nlh->nlmsg_type, ifindex, dst); + if (sync_needed) + synchronize_rcu(); return err; }