From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Sedat Dilek <sedat.dilek@gmail.com>,
Guillaume Nault <g.nault@alphalink.fr>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.2 25/30] ppp: fix lockdep splat in ppp_dev_uninit()
Date: Thu, 1 Oct 2015 11:21:47 +0200 [thread overview]
Message-ID: <20151001092039.281806398@linuxfoundation.org> (raw)
In-Reply-To: <20151001092038.213304276@linuxfoundation.org>
4.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Guillaume Nault <g.nault@alphalink.fr>
[ Upstream commit 58a89ecaca53736aa465170530acea4f8be34ab4 ]
ppp_dev_uninit() locks all_ppp_mutex while under rtnl mutex protection.
ppp_create_interface() must then lock these mutexes in that same order
to avoid possible deadlock.
[ 120.880011] ======================================================
[ 120.880011] [ INFO: possible circular locking dependency detected ]
[ 120.880011] 4.2.0 #1 Not tainted
[ 120.880011] -------------------------------------------------------
[ 120.880011] ppp-apitest/15827 is trying to acquire lock:
[ 120.880011] (&pn->all_ppp_mutex){+.+.+.}, at: [<ffffffffa0145f56>] ppp_dev_uninit+0x64/0xb0 [ppp_generic]
[ 120.880011]
[ 120.880011] but task is already holding lock:
[ 120.880011] (rtnl_mutex){+.+.+.}, at: [<ffffffff812e4255>] rtnl_lock+0x12/0x14
[ 120.880011]
[ 120.880011] which lock already depends on the new lock.
[ 120.880011]
[ 120.880011]
[ 120.880011] the existing dependency chain (in reverse order) is:
[ 120.880011]
[ 120.880011] -> #1 (rtnl_mutex){+.+.+.}:
[ 120.880011] [<ffffffff81073a6f>] lock_acquire+0xcf/0x10e
[ 120.880011] [<ffffffff813ab18a>] mutex_lock_nested+0x56/0x341
[ 120.880011] [<ffffffff812e4255>] rtnl_lock+0x12/0x14
[ 120.880011] [<ffffffff812d9d94>] register_netdev+0x11/0x27
[ 120.880011] [<ffffffffa0147b17>] ppp_ioctl+0x289/0xc98 [ppp_generic]
[ 120.880011] [<ffffffff8113b367>] do_vfs_ioctl+0x4ea/0x532
[ 120.880011] [<ffffffff8113b3fd>] SyS_ioctl+0x4e/0x7d
[ 120.880011] [<ffffffff813ad7d7>] entry_SYSCALL_64_fastpath+0x12/0x6f
[ 120.880011]
[ 120.880011] -> #0 (&pn->all_ppp_mutex){+.+.+.}:
[ 120.880011] [<ffffffff8107334e>] __lock_acquire+0xb07/0xe76
[ 120.880011] [<ffffffff81073a6f>] lock_acquire+0xcf/0x10e
[ 120.880011] [<ffffffff813ab18a>] mutex_lock_nested+0x56/0x341
[ 120.880011] [<ffffffffa0145f56>] ppp_dev_uninit+0x64/0xb0 [ppp_generic]
[ 120.880011] [<ffffffff812d5263>] rollback_registered_many+0x19e/0x252
[ 120.880011] [<ffffffff812d5381>] rollback_registered+0x29/0x38
[ 120.880011] [<ffffffff812d53fa>] unregister_netdevice_queue+0x6a/0x77
[ 120.880011] [<ffffffffa0146a94>] ppp_release+0x42/0x79 [ppp_generic]
[ 120.880011] [<ffffffff8112d9f6>] __fput+0xec/0x192
[ 120.880011] [<ffffffff8112dacc>] ____fput+0x9/0xb
[ 120.880011] [<ffffffff8105447a>] task_work_run+0x66/0x80
[ 120.880011] [<ffffffff81001801>] prepare_exit_to_usermode+0x8c/0xa7
[ 120.880011] [<ffffffff81001900>] syscall_return_slowpath+0xe4/0x104
[ 120.880011] [<ffffffff813ad931>] int_ret_from_sys_call+0x25/0x9f
[ 120.880011]
[ 120.880011] other info that might help us debug this:
[ 120.880011]
[ 120.880011] Possible unsafe locking scenario:
[ 120.880011]
[ 120.880011] CPU0 CPU1
[ 120.880011] ---- ----
[ 120.880011] lock(rtnl_mutex);
[ 120.880011] lock(&pn->all_ppp_mutex);
[ 120.880011] lock(rtnl_mutex);
[ 120.880011] lock(&pn->all_ppp_mutex);
[ 120.880011]
[ 120.880011] *** DEADLOCK ***
Fixes: 8cb775bc0a34 ("ppp: fix device unregistration upon netns deletion")
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ppp/ppp_generic.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -2742,6 +2742,7 @@ static struct ppp *ppp_create_interface(
*/
dev_net_set(dev, net);
+ rtnl_lock();
mutex_lock(&pn->all_ppp_mutex);
if (unit < 0) {
@@ -2772,7 +2773,7 @@ static struct ppp *ppp_create_interface(
ppp->file.index = unit;
sprintf(dev->name, "ppp%d", unit);
- ret = register_netdev(dev);
+ ret = register_netdevice(dev);
if (ret != 0) {
unit_put(&pn->units_idr, unit);
netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
@@ -2784,6 +2785,7 @@ static struct ppp *ppp_create_interface(
atomic_inc(&ppp_unit_count);
mutex_unlock(&pn->all_ppp_mutex);
+ rtnl_unlock();
*retp = 0;
return ppp;
next prev parent reply other threads:[~2015-10-01 9:23 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-01 9:21 [PATCH 4.2 00/30] 4.2.3-stable review Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 01/30] phylib: fix device deletion order in mdiobus_unregister() Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 02/30] sock, diag: fix panic in sock_diag_put_filterinfo Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 03/30] ipv6: fix exthdrs offload registration in out_rt path Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 04/30] net: fec: clear receive interrupts before processing a packet Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 05/30] net: eth: altera: fix napi poll_list corruption Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 06/30] net/ipv6: Correct PIM6 mrt_lock handling Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 07/30] net: dsa: bcm_sf2: Fix ageing conditions and operation Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 08/30] ipv6: fix multipath route replace error recovery Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 09/30] net: dsa: bcm_sf2: Fix 64-bits register writes Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 10/30] netlink, mmap: transform mmap skb into full skb on taps Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 11/30] sctp: fix race on protocol/netns initialization Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 13/30] net: mvneta: fix DMA buffer unmapping in mvneta_rx() Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 14/30] rtnetlink: catch -EOPNOTSUPP errors from ndo_bridge_getlink Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 15/30] net/mlx4_en: really allow to change RSS key Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 16/30] macvtap: fix TUNSETSNDBUF values > 64k Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 17/30] netlink: Fix autobind race condition that leads to zero port ID Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 18/30] netlink: Replace rhash_portid with bound Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 19/30] net: dsa: actually force the speed on the CPU port Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 20/30] openvswitch: Zero flows on allocation Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 21/30] tcp: add proper TS val into RST packets Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 22/30] Fix AF_PACKET ABI breakage in 4.2 Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 23/30] net: revert "net_sched: move tp->root allocation into fw_init()" Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 24/30] fib_rules: fix fib rule dumps across multiple skbs Greg Kroah-Hartman
2015-10-01 9:21 ` Greg Kroah-Hartman [this message]
2015-10-01 9:21 ` [PATCH 4.2 26/30] net: dsa: bcm_sf2: Do not override speed settings Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 27/30] net: phy: fixed_phy: handle link-down case Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 28/30] of_mdio: add new DT property managed to specify the PHY management type Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 29/30] mvneta: use inband status only when explicitly enabled Greg Kroah-Hartman
2015-10-01 9:21 ` [PATCH 4.2 30/30] net/mlx4_core: Capping number of requested MSIXs to MAX_MSIX Greg Kroah-Hartman
2015-10-02 1:27 ` [PATCH 4.2 00/30] 4.2.3-stable review Guenter Roeck
2015-10-03 11:37 ` Greg Kroah-Hartman
2015-10-03 14:45 ` Guenter Roeck
2015-10-18 0:45 ` Greg Kroah-Hartman
2015-10-02 5:14 ` Sudip Mukherjee
2015-10-03 11:36 ` Greg Kroah-Hartman
2015-10-02 15:41 ` Shuah Khan
2015-10-03 11:36 ` Greg Kroah-Hartman
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