From 9a5a90d167b0e5fe3d47af16b68fd09ce64085cd Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Thu, 28 Mar 2019 18:23:04 +0300 Subject: net: core: netif_receive_skb_list: unlist skb before passing to pt->func __netif_receive_skb_list_ptype() leaves skb->next poisoned before passing it to pt_prev->func handler, what may produce (in certain cases, e.g. DSA setup) crashes like: [ 88.606777] CPU 0 Unable to handle kernel paging request at virtual address 0000000e, epc == 80687078, ra == 8052cc7c [ 88.618666] Oops[#1]: [ 88.621196] CPU: 0 PID: 0 Comm: swapper Not tainted 5.1.0-rc2-dlink-00206-g4192a172-dirty #1473 [ 88.630885] $ 0 : 00000000 10000400 00000002 864d7850 [ 88.636709] $ 4 : 87c0ddf0 864d7800 87c0ddf0 00000000 [ 88.642526] $ 8 : 00000000 49600000 00000001 00000001 [ 88.648342] $12 : 00000000 c288617b dadbee27 25d17c41 [ 88.654159] $16 : 87c0ddf0 85cff080 80790000 fffffffd [ 88.659975] $20 : 80797b20 ffffffff 00000001 864d7800 [ 88.665793] $24 : 00000000 8011e658 [ 88.671609] $28 : 80790000 87c0dbc0 87cabf00 8052cc7c [ 88.677427] Hi : 00000003 [ 88.680622] Lo : 7b5b4220 [ 88.683840] epc : 80687078 vlan_dev_hard_start_xmit+0x1c/0x1a0 [ 88.690532] ra : 8052cc7c dev_hard_start_xmit+0xac/0x188 [ 88.696734] Status: 10000404 IEp [ 88.700422] Cause : 50000008 (ExcCode 02) [ 88.704874] BadVA : 0000000e [ 88.708069] PrId : 0001a120 (MIPS interAptiv (multi)) [ 88.713005] Modules linked in: [ 88.716407] Process swapper (pid: 0, threadinfo=(ptrval), task=(ptrval), tls=00000000) [ 88.725219] Stack : 85f61c28 00000000 0000000e 80780000 87c0ddf0 85cff080 80790000 8052cc7c [ 88.734529] 87cabf00 00000000 00000001 85f5fb40 807b0000 864d7850 87cabf00 807d0000 [ 88.743839] 864d7800 8655f600 00000000 85cff080 87c1c000 0000006a 00000000 8052d96c [ 88.753149] 807a0000 8057adb8 87c0dcc8 87c0dc50 85cfff08 00000558 87cabf00 85f58c50 [ 88.762460] 00000002 85f58c00 864d7800 80543308 fffffff4 00000001 85f58c00 864d7800 [ 88.771770] ... [ 88.774483] Call Trace: [ 88.777199] [<80687078>] vlan_dev_hard_start_xmit+0x1c/0x1a0 [ 88.783504] [<8052cc7c>] dev_hard_start_xmit+0xac/0x188 [ 88.789326] [<8052d96c>] __dev_queue_xmit+0x6e8/0x7d4 [ 88.794955] [<805a8640>] ip_finish_output2+0x238/0x4d0 [ 88.800677] [<805ab6a0>] ip_output+0xc8/0x140 [ 88.805526] [<805a68f4>] ip_forward+0x364/0x560 [ 88.810567] [<805a4ff8>] ip_rcv+0x48/0xe4 [ 88.815030] [<80528d44>] __netif_receive_skb_one_core+0x44/0x58 [ 88.821635] [<8067f220>] dsa_switch_rcv+0x108/0x1ac [ 88.827067] [<80528f80>] __netif_receive_skb_list_core+0x228/0x26c [ 88.833951] [<8052ed84>] netif_receive_skb_list+0x1d4/0x394 [ 88.840160] [<80355a88>] lunar_rx_poll+0x38c/0x828 [ 88.845496] [<8052fa78>] net_rx_action+0x14c/0x3cc [ 88.850835] [<806ad300>] __do_softirq+0x178/0x338 [ 88.856077] [<8012a2d4>] irq_exit+0xbc/0x100 [ 88.860846] [<802f8b70>] plat_irq_dispatch+0xc0/0x144 [ 88.866477] [<80105974>] handle_int+0x14c/0x158 [ 88.871516] [<806acfb0>] r4k_wait+0x30/0x40 [ 88.876462] Code: afb10014 8c8200a0 00803025 <9443000c> 94a20468 00000000 10620042 00a08025 9605046a [ 88.887332] [ 88.888982] ---[ end trace eb863d007da11cf1 ]--- [ 88.894122] Kernel panic - not syncing: Fatal exception in interrupt [ 88.901202] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- Fix this by pulling skb off the sublist and zeroing skb->next pointer before calling ptype callback. Fixes: 88eb1944e18c ("net: core: propagate SKB lists through packet_type lookup") Reviewed-by: Edward Cree Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller --- net/core/dev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 2b67f2aa59dd..fdcff29df915 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5014,8 +5014,10 @@ static inline void __netif_receive_skb_list_ptype(struct list_head *head, if (pt_prev->list_func != NULL) pt_prev->list_func(head, pt_prev, orig_dev); else - list_for_each_entry_safe(skb, next, head, list) + list_for_each_entry_safe(skb, next, head, list) { + skb_list_del_init(skb); pt_prev->func(skb, skb->dev, pt_prev, orig_dev); + } } static void __netif_receive_skb_list_core(struct list_head *head, bool pfmemalloc) -- cgit From 8065a779f17e94536a1c4dcee4f9d88011672f97 Mon Sep 17 00:00:00 2001 From: Si-Wei Liu Date: Mon, 8 Apr 2019 19:45:27 -0400 Subject: failover: allow name change on IFF_UP slave interfaces When a netdev appears through hot plug then gets enslaved by a failover master that is already up and running, the slave will be opened right away after getting enslaved. Today there's a race that userspace (udev) may fail to rename the slave if the kernel (net_failover) opens the slave earlier than when the userspace rename happens. Unlike bond or team, the primary slave of failover can't be renamed by userspace ahead of time, since the kernel initiated auto-enslavement is unable to, or rather, is never meant to be synchronized with the rename request from userspace. As the failover slave interfaces are not designed to be operated directly by userspace apps: IP configuration, filter rules with regard to network traffic passing and etc., should all be done on master interface. In general, userspace apps only care about the name of master interface, while slave names are less important as long as admin users can see reliable names that may carry other information describing the netdev. For e.g., they can infer that "ens3nsby" is a standby slave of "ens3", while for a name like "eth0" they can't tell which master it belongs to. Historically the name of IFF_UP interface can't be changed because there might be admin script or management software that is already relying on such behavior and assumes that the slave name can't be changed once UP. But failover is special: with the in-kernel auto-enslavement mechanism, the userspace expectation for device enumeration and bring-up order is already broken. Previously initramfs and various userspace config tools were modified to bypass failover slaves because of auto-enslavement and duplicate MAC address. Similarly, in case that users care about seeing reliable slave name, the new type of failover slaves needs to be taken care of specifically in userspace anyway. It's less risky to lift up the rename restriction on failover slave which is already UP. Although it's possible this change may potentially break userspace component (most likely configuration scripts or management software) that assumes slave name can't be changed while UP, it's relatively a limited and controllable set among all userspace components, which can be fixed specifically to listen for the rename events on failover slaves. Userspace component interacting with slaves is expected to be changed to operate on failover master interface instead, as the failover slave is dynamic in nature which may come and go at any point. The goal is to make the role of failover slaves less relevant, and userspace components should only deal with failover master in the long run. Fixes: 30c8bd5aa8b2 ("net: Introduce generic failover module") Signed-off-by: Si-Wei Liu Reviewed-by: Liran Alon Acked-by: Sridhar Samudrala Signed-off-by: David S. Miller --- net/core/dev.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index fdcff29df915..f409406254dd 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1184,7 +1184,21 @@ int dev_change_name(struct net_device *dev, const char *newname) BUG_ON(!dev_net(dev)); net = dev_net(dev); - if (dev->flags & IFF_UP) + + /* Some auto-enslaved devices e.g. failover slaves are + * special, as userspace might rename the device after + * the interface had been brought up and running since + * the point kernel initiated auto-enslavement. Allow + * live name change even when these slave devices are + * up and running. + * + * Typically, users of these auto-enslaving devices + * don't actually care about slave name change, as + * they are supposed to operate on master interface + * directly. + */ + if (dev->flags & IFF_UP && + likely(!(dev->priv_flags & IFF_LIVE_RENAME_OK))) return -EBUSY; write_seqcount_begin(&devnet_rename_seq); -- cgit