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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Saeed Mahameed <saeed@kernel.org>,
	Ivan Vecera <ivecera@redhat.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Jiri Pirko <jiri@nvidia.com>, Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 4.19 36/37] team: protect features update by RCU to avoid deadlock
Date: Tue,  2 Feb 2021 14:39:19 +0100	[thread overview]
Message-ID: <20210202132944.440388535@linuxfoundation.org> (raw)
In-Reply-To: <20210202132942.915040339@linuxfoundation.org>

From: Ivan Vecera <ivecera@redhat.com>

commit f0947d0d21b219e03940b9be6628a43445c0de7a upstream.

Function __team_compute_features() is protected by team->lock
mutex when it is called from team_compute_features() used when
features of an underlying device is changed. This causes
a deadlock when NETDEV_FEAT_CHANGE notifier for underlying device
is fired due to change propagated from team driver (e.g. MTU
change). It's because callbacks like team_change_mtu() or
team_vlan_rx_{add,del}_vid() protect their port list traversal
by team->lock mutex.

Example (r8169 case where this driver disables TSO for certain MTU
values):
...
[ 6391.348202]  __mutex_lock.isra.6+0x2d0/0x4a0
[ 6391.358602]  team_device_event+0x9d/0x160 [team]
[ 6391.363756]  notifier_call_chain+0x47/0x70
[ 6391.368329]  netdev_update_features+0x56/0x60
[ 6391.373207]  rtl8169_change_mtu+0x14/0x50 [r8169]
[ 6391.378457]  dev_set_mtu_ext+0xe1/0x1d0
[ 6391.387022]  dev_set_mtu+0x52/0x90
[ 6391.390820]  team_change_mtu+0x64/0xf0 [team]
[ 6391.395683]  dev_set_mtu_ext+0xe1/0x1d0
[ 6391.399963]  do_setlink+0x231/0xf50
...

In fact team_compute_features() called from team_device_event()
does not need to be protected by team->lock mutex and rcu_read_lock()
is sufficient there for port list traversal.

Fixes: 3d249d4ca7d0 ("net: introduce ethernet teaming device")
Cc: Saeed Mahameed <saeed@kernel.org>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20210125074416.4056484-1-ivecera@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/team/team.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -998,7 +998,8 @@ static void __team_compute_features(stru
 	unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
 					IFF_XMIT_DST_RELEASE_PERM;
 
-	list_for_each_entry(port, &team->port_list, list) {
+	rcu_read_lock();
+	list_for_each_entry_rcu(port, &team->port_list, list) {
 		vlan_features = netdev_increment_features(vlan_features,
 					port->dev->vlan_features,
 					TEAM_VLAN_FEATURES);
@@ -1012,6 +1013,7 @@ static void __team_compute_features(stru
 		if (port->dev->hard_header_len > max_hard_header_len)
 			max_hard_header_len = port->dev->hard_header_len;
 	}
+	rcu_read_unlock();
 
 	team->dev->vlan_features = vlan_features;
 	team->dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL |
@@ -1027,9 +1029,7 @@ static void __team_compute_features(stru
 
 static void team_compute_features(struct team *team)
 {
-	mutex_lock(&team->lock);
 	__team_compute_features(team);
-	mutex_unlock(&team->lock);
 	netdev_change_features(team->dev);
 }
 



  parent reply	other threads:[~2021-02-02 14:25 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02 13:38 [PATCH 4.19 00/37] 4.19.173-rc1 review Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 01/37] nbd: freeze the queue while were adding connections Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 02/37] ACPI: sysfs: Prefer "compatible" modalias Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 03/37] kernel: kexec: remove the lock operation of system_transition_mutex Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 04/37] xen/privcmd: allow fetching resource sizes Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 05/37] ALSA: hda/via: Apply the workaround generically for Clevo machines Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 06/37] media: rc: ensure that uevent can be read directly after rc device register Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 07/37] ARM: dts: imx6qdl-gw52xx: fix duplicate regulator naming Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 08/37] wext: fix NULL-ptr-dereference with cfg80211s lack of commit() Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 09/37] net: usb: qmi_wwan: added support for Thales Cinterion PLSx3 modem family Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 10/37] PM: hibernate: flush swap writer after marking Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 11/37] drivers: soc: atmel: Avoid calling at91_soc_init on non AT91 SoCs Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 12/37] drivers: soc: atmel: add null entry at the end of at91_soc_allowed_list[] Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 13/37] KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[] Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 14/37] KVM: x86: get smi pending status correctly Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 15/37] xen: Fix XenStore initialisation for XS_LOCAL Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.19 16/37] leds: trigger: fix potential deadlock with libata Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 17/37] mt7601u: fix kernel crash unplugging the device Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 18/37] mt7601u: fix rx buffer refcounting Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 19/37] xen-blkfront: allow discard-* nodes to be optional Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 20/37] ARM: imx: build suspend-imx6.S with arm instruction set Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 21/37] netfilter: nft_dynset: add timeout extension to template Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 22/37] xfrm: Fix oops in xfrm_replay_advance_bmp Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 23/37] xfrm: fix disable_xfrm sysctl when used on xfrm interfaces Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 24/37] RDMA/cxgb4: Fix the reported max_recv_sge value Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 25/37] pNFS/NFSv4: Fix a layout segment leak in pnfs_layout_process() Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 26/37] iwlwifi: pcie: use jiffies for memory read spin time limit Greg Kroah-Hartman
2021-02-03 20:42   ` Pavel Machek
2021-02-02 13:39 ` [PATCH 4.19 27/37] iwlwifi: pcie: reschedule in long-running memory reads Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 28/37] mac80211: pause TX while changing interface type Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 29/37] net/mlx5: Fix memory leak on flow table creation error flow Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 30/37] can: dev: prevent potential information leak in can_fill_info() Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 31/37] iommu/vt-d: Gracefully handle DMAR units with no supported address widths Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 32/37] iommu/vt-d: Dont dereference iommu_device if IOMMU_API is not built Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 33/37] rxrpc: Fix memory leak in rxrpc_lookup_local Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 34/37] NFC: fix resource leak when target index is invalid Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.19 35/37] NFC: fix possible resource leak Greg Kroah-Hartman
2021-02-02 13:39 ` Greg Kroah-Hartman [this message]
2021-02-02 13:39 ` [PATCH 4.19 37/37] tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN Greg Kroah-Hartman
2021-02-02 17:48 ` [PATCH 4.19 00/37] 4.19.173-rc1 review Pavel Machek
2021-02-02 20:21 ` Jon Hunter
2021-02-03  3:22 ` Naresh Kamboju
2021-02-03 15:42 ` Shuah Khan
2021-02-03 20:42 ` Guenter Roeck

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