linux-stable.git/net/core, branch v3.18.49 Linux kernel stable tree net: fix socket refcounting in skb_complete_tx_timestamp() 2017-04-18T05:55:54+00:00 Eric Dumazet edumazet@google.com 2017-03-04T05:01:03+00:00 61cc261bd334b3e360def9b91558fdd5937fd525 commit 9ac25fc063751379cb77434fef9f3b088cd3e2f7 upstream. TX skbs do not necessarily hold a reference on skb->sk->sk_refcnt By the time TX completion happens, sk_refcnt might be already 0. sock_hold()/sock_put() would then corrupt critical state, like sk_wmem_alloc and lead to leaks or use after free. Fixes: 62bccb8cdb69 ("net-timestamp: Make the clone operation stand-alone from phy timestamping") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexander Duyck <alexander.h.duyck@intel.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Willem de Bruijn <willemb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9ac25fc063751379cb77434fef9f3b088cd3e2f7 upstream.

TX skbs do not necessarily hold a reference on skb->sk->sk_refcnt
By the time TX completion happens, sk_refcnt might be already 0.

sock_hold()/sock_put() would then corrupt critical state, like
sk_wmem_alloc and lead to leaks or use after free.

Fixes: 62bccb8cdb69 ("net-timestamp: Make the clone operation stand-alone from phy timestamping")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: fix socket refcounting in skb_complete_wifi_ack() 2017-04-18T05:55:54+00:00 Eric Dumazet edumazet@google.com 2017-03-04T05:01:02+00:00 66aebd46a4d73f8685f275a23d58fff4985df448 commit dd4f10722aeb10f4f582948839f066bebe44e5fb upstream. TX skbs do not necessarily hold a reference on skb->sk->sk_refcnt By the time TX completion happens, sk_refcnt might be already 0. sock_hold()/sock_put() would then corrupt critical state, like sk_wmem_alloc. Fixes: bf7fa551e0ce ("mac80211: Resolve sk_refcnt/sk_wmem_alloc issue in wifi ack path") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexander Duyck <alexander.h.duyck@intel.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Willem de Bruijn <willemb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit dd4f10722aeb10f4f582948839f066bebe44e5fb upstream.

TX skbs do not necessarily hold a reference on skb->sk->sk_refcnt
By the time TX completion happens, sk_refcnt might be already 0.

sock_hold()/sock_put() would then corrupt critical state, like
sk_wmem_alloc.

Fixes: bf7fa551e0ce ("mac80211: Resolve sk_refcnt/sk_wmem_alloc issue in wifi ack path")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
packet: on direct_xmit, limit tso and csum to supported devices 2017-04-18T05:55:47+00:00 Willem de Bruijn willemb@google.com 2016-10-26T15:23:07+00:00 d85e6fee91b4538b3ffe39c88f08482304504c74 [ Upstream commit 104ba78c98808ae837d1f63aae58c183db5505df ] When transmitting on a packet socket with PACKET_VNET_HDR and PACKET_QDISC_BYPASS, validate device support for features requested in vnet_hdr. Drop TSO packets sent to devices that do not support TSO or have the feature disabled. Note that the latter currently do process those packets correctly, regardless of not advertising the feature. Because of SKB_GSO_DODGY, it is not sufficient to test device features with netif_needs_gso. Full validate_xmit_skb is needed. Switch to software checksum for non-TSO packets that request checksum offload if that device feature is unsupported or disabled. Note that similar to the TSO case, device drivers may perform checksum offload correctly even when not advertising it. When switching to software checksum, packets hit skb_checksum_help, which has two BUG_ON checksum not in linear segment. Packet sockets always allocate at least up to csum_start + csum_off + 2 as linear. Tested by running github.com/wdebruij/kerneltools/psock_txring_vnet.c ethtool -K eth0 tso off tx on psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v -N ethtool -K eth0 tx off psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G -N v2: - add EXPORT_SYMBOL_GPL(validate_xmit_skb_list) Fixes: d346a3fae3ff ("packet: introduce PACKET_QDISC_BYPASS socket option") Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 104ba78c98808ae837d1f63aae58c183db5505df ]

When transmitting on a packet socket with PACKET_VNET_HDR and
PACKET_QDISC_BYPASS, validate device support for features requested
in vnet_hdr.

Drop TSO packets sent to devices that do not support TSO or have the
feature disabled. Note that the latter currently do process those
packets correctly, regardless of not advertising the feature.

Because of SKB_GSO_DODGY, it is not sufficient to test device features
with netif_needs_gso. Full validate_xmit_skb is needed.

Switch to software checksum for non-TSO packets that request checksum
offload if that device feature is unsupported or disabled. Note that
similar to the TSO case, device drivers may perform checksum offload
correctly even when not advertising it.

When switching to software checksum, packets hit skb_checksum_help,
which has two BUG_ON checksum not in linear segment. Packet sockets
always allocate at least up to csum_start + csum_off + 2 as linear.

Tested by running github.com/wdebruij/kerneltools/psock_txring_vnet.c

  ethtool -K eth0 tso off tx on
  psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v
  psock_txring_vnet -d $dst -s $src -i eth0 -l 2000 -n 1 -q -v -N

  ethtool -K eth0 tx off
  psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G
  psock_txring_vnet -d $dst -s $src -i eth0 -l 1000 -n 1 -q -v -G -N

v2:
  - add EXPORT_SYMBOL_GPL(validate_xmit_skb_list)

Fixes: d346a3fae3ff ("packet: introduce PACKET_QDISC_BYPASS socket option")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: pktgen: remove rcu locking in pktgen_change_name() 2017-04-18T05:55:46+00:00 Eric Dumazet edumazet@google.com 2016-10-15T15:50:49+00:00 183a18e1d2b20881f4be48d4c8cc6ed6c5f2c4fa [ Upstream commit 9a0b1e8ba4061778897b544afc898de2163382f7 ] After Jesper commit back in linux-3.18, we trigger a lockdep splat in proc_create_data() while allocating memory from pktgen_change_name(). This patch converts t->if_lock to a mutex, since it is now only used from control path, and adds proper locking to pktgen_change_name() 1) pktgen_thread_lock to protect the outer loop (iterating threads) 2) t->if_lock to protect the inner loop (iterating devices) Note that before Jesper patch, pktgen_change_name() was lacking proper protection, but lockdep was not able to detect the problem. Fixes: 8788370a1d4b ("pktgen: RCU-ify "if_list" to remove lock in next_to_run()") Reported-by: John Sperbeck <jsperbeck@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 9a0b1e8ba4061778897b544afc898de2163382f7 ]

After Jesper commit back in linux-3.18, we trigger a lockdep
splat in proc_create_data() while allocating memory from
pktgen_change_name().

This patch converts t->if_lock to a mutex, since it is now only
used from control path, and adds proper locking to pktgen_change_name()

1) pktgen_thread_lock to protect the outer loop (iterating threads)
2) t->if_lock to protect the inner loop (iterating devices)

Note that before Jesper patch, pktgen_change_name() was lacking proper
protection, but lockdep was not able to detect the problem.

Fixes: 8788370a1d4b ("pktgen: RCU-ify "if_list" to remove lock in next_to_run()")
Reported-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: Add netdev all_adj_list refcnt propagation to fix panic 2017-04-18T05:55:46+00:00 Andrew Collins acollins@cradlepoint.com 2016-10-03T19:43:02+00:00 bd73f80dccf3377f985e564f885778f9c2b29d19 [ Upstream commit 93409033ae653f1c9a949202fb537ab095b2092f ] This is a respin of a patch to fix a relatively easily reproducible kernel panic related to the all_adj_list handling for netdevs in recent kernels. The following sequence of commands will reproduce the issue: ip link add link eth0 name eth0.100 type vlan id 100 ip link add link eth0 name eth0.200 type vlan id 200 ip link add name testbr type bridge ip link set eth0.100 master testbr ip link set eth0.200 master testbr ip link add link testbr mac0 type macvlan ip link delete dev testbr This creates an upper/lower tree of (excuse the poor ASCII art): /---eth0.100-eth0 mac0-testbr- \---eth0.200-eth0 When testbr is deleted, the all_adj_lists are walked, and eth0 is deleted twice from the mac0 list. Unfortunately, during setup in __netdev_upper_dev_link, only one reference to eth0 is added, so this results in a panic. This change adds reference count propagation so things are handled properly. Matthias Schiffer reported a similar crash in batman-adv: https://github.com/freifunk-gluon/gluon/issues/680 https://www.open-mesh.org/issues/247 which this patch also seems to resolve. Signed-off-by: Andrew Collins <acollins@cradlepoint.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 93409033ae653f1c9a949202fb537ab095b2092f ]

This is a respin of a patch to fix a relatively easily reproducible kernel
panic related to the all_adj_list handling for netdevs in recent kernels.

The following sequence of commands will reproduce the issue:

ip link add link eth0 name eth0.100 type vlan id 100
ip link add link eth0 name eth0.200 type vlan id 200
ip link add name testbr type bridge
ip link set eth0.100 master testbr
ip link set eth0.200 master testbr
ip link add link testbr mac0 type macvlan
ip link delete dev testbr

This creates an upper/lower tree of (excuse the poor ASCII art):

            /---eth0.100-eth0
mac0-testbr-
            \---eth0.200-eth0

When testbr is deleted, the all_adj_lists are walked, and eth0 is deleted twice from
the mac0 list. Unfortunately, during setup in __netdev_upper_dev_link, only one
reference to eth0 is added, so this results in a panic.

This change adds reference count propagation so things are handled properly.

Matthias Schiffer reported a similar crash in batman-adv:

https://github.com/freifunk-gluon/gluon/issues/680
https://www.open-mesh.org/issues/247

which this patch also seems to resolve.

Signed-off-by: Andrew Collins <acollins@cradlepoint.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: use a work queue to defer net_disable_timestamp() work 2017-04-18T05:55:43+00:00 Eric Dumazet edumazet@google.com 2017-02-02T18:31:35+00:00 1d3dbc1df5dc1372b0403c0c8f8ce77021a9512d [ Upstream commit 5fa8bbda38c668e56b0c6cdecced2eac2fe36dec ] Dmitry reported a warning [1] showing that we were calling net_disable_timestamp() -> static_key_slow_dec() from a non process context. Grabbing a mutex while holding a spinlock or rcu_read_lock() is not allowed. As Cong suggested, we now use a work queue. It is possible netstamp_clear() exits while netstamp_needed_deferred is not zero, but it is probably not worth trying to do better than that. netstamp_needed_deferred atomic tracks the exact number of deferred decrements. [1] [ INFO: suspicious RCU usage. ] 4.10.0-rc5+ #192 Not tainted ------------------------------- ./include/linux/rcupdate.h:561 Illegal context switch in RCU read-side critical section! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 2 locks held by syz-executor14/23111: #0: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff83a35c35>] lock_sock include/net/sock.h:1454 [inline] #0: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff83a35c35>] rawv6_sendmsg+0x1e65/0x3ec0 net/ipv6/raw.c:919 #1: (rcu_read_lock){......}, at: [<ffffffff83ae2678>] nf_hook include/linux/netfilter.h:201 [inline] #1: (rcu_read_lock){......}, at: [<ffffffff83ae2678>] __ip6_local_out+0x258/0x840 net/ipv6/output_core.c:160 stack backtrace: CPU: 2 PID: 23111 Comm: syz-executor14 Not tainted 4.10.0-rc5+ #192 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:15 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:51 lockdep_rcu_suspicious+0x139/0x180 kernel/locking/lockdep.c:4452 rcu_preempt_sleep_check include/linux/rcupdate.h:560 [inline] ___might_sleep+0x560/0x650 kernel/sched/core.c:7748 __might_sleep+0x95/0x1a0 kernel/sched/core.c:7739 mutex_lock_nested+0x24f/0x1730 kernel/locking/mutex.c:752 atomic_dec_and_mutex_lock+0x119/0x160 kernel/locking/mutex.c:1060 __static_key_slow_dec+0x7a/0x1e0 kernel/jump_label.c:149 static_key_slow_dec+0x51/0x90 kernel/jump_label.c:174 net_disable_timestamp+0x3b/0x50 net/core/dev.c:1728 sock_disable_timestamp+0x98/0xc0 net/core/sock.c:403 __sk_destruct+0x27d/0x6b0 net/core/sock.c:1441 sk_destruct+0x47/0x80 net/core/sock.c:1460 __sk_free+0x57/0x230 net/core/sock.c:1468 sock_wfree+0xae/0x120 net/core/sock.c:1645 skb_release_head_state+0xfc/0x200 net/core/skbuff.c:655 skb_release_all+0x15/0x60 net/core/skbuff.c:668 __kfree_skb+0x15/0x20 net/core/skbuff.c:684 kfree_skb+0x16e/0x4c0 net/core/skbuff.c:705 inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304 inet_frag_put include/net/inet_frag.h:133 [inline] nf_ct_frag6_gather+0x1106/0x3840 net/ipv6/netfilter/nf_conntrack_reasm.c:617 ipv6_defrag+0x1be/0x2b0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68 nf_hook_entry_hookfn include/linux/netfilter.h:102 [inline] nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310 nf_hook include/linux/netfilter.h:212 [inline] __ip6_local_out+0x489/0x840 net/ipv6/output_core.c:160 ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170 ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline] rawv6_sendmsg+0x2d1a/0x3ec0 net/ipv6/raw.c:927 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xca/0x110 net/socket.c:645 sock_write_iter+0x326/0x600 net/socket.c:848 do_iter_readv_writev+0x2e3/0x5b0 fs/read_write.c:695 do_readv_writev+0x42c/0x9b0 fs/read_write.c:872 vfs_writev+0x87/0xc0 fs/read_write.c:911 do_writev+0x110/0x2c0 fs/read_write.c:944 SYSC_writev fs/read_write.c:1017 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1014 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x445559 RSP: 002b:00007f6f46fceb58 EFLAGS: 00000292 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000445559 RDX: 0000000000000001 RSI: 0000000020f1eff0 RDI: 0000000000000005 RBP: 00000000006e19c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000700000 R13: 0000000020f59000 R14: 0000000000000015 R15: 0000000000020400 BUG: sleeping function called from invalid context at kernel/locking/mutex.c:752 in_atomic(): 1, irqs_disabled(): 0, pid: 23111, name: syz-executor14 INFO: lockdep is turned off. CPU: 2 PID: 23111 Comm: syz-executor14 Not tainted 4.10.0-rc5+ #192 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:15 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:51 ___might_sleep+0x47e/0x650 kernel/sched/core.c:7780 __might_sleep+0x95/0x1a0 kernel/sched/core.c:7739 mutex_lock_nested+0x24f/0x1730 kernel/locking/mutex.c:752 atomic_dec_and_mutex_lock+0x119/0x160 kernel/locking/mutex.c:1060 __static_key_slow_dec+0x7a/0x1e0 kernel/jump_label.c:149 static_key_slow_dec+0x51/0x90 kernel/jump_label.c:174 net_disable_timestamp+0x3b/0x50 net/core/dev.c:1728 sock_disable_timestamp+0x98/0xc0 net/core/sock.c:403 __sk_destruct+0x27d/0x6b0 net/core/sock.c:1441 sk_destruct+0x47/0x80 net/core/sock.c:1460 __sk_free+0x57/0x230 net/core/sock.c:1468 sock_wfree+0xae/0x120 net/core/sock.c:1645 skb_release_head_state+0xfc/0x200 net/core/skbuff.c:655 skb_release_all+0x15/0x60 net/core/skbuff.c:668 __kfree_skb+0x15/0x20 net/core/skbuff.c:684 kfree_skb+0x16e/0x4c0 net/core/skbuff.c:705 inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304 inet_frag_put include/net/inet_frag.h:133 [inline] nf_ct_frag6_gather+0x1106/0x3840 net/ipv6/netfilter/nf_conntrack_reasm.c:617 ipv6_defrag+0x1be/0x2b0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68 nf_hook_entry_hookfn include/linux/netfilter.h:102 [inline] nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310 nf_hook include/linux/netfilter.h:212 [inline] __ip6_local_out+0x489/0x840 net/ipv6/output_core.c:160 ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170 ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline] rawv6_sendmsg+0x2d1a/0x3ec0 net/ipv6/raw.c:927 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xca/0x110 net/socket.c:645 sock_write_iter+0x326/0x600 net/socket.c:848 do_iter_readv_writev+0x2e3/0x5b0 fs/read_write.c:695 do_readv_writev+0x42c/0x9b0 fs/read_write.c:872 vfs_writev+0x87/0xc0 fs/read_write.c:911 do_writev+0x110/0x2c0 fs/read_write.c:944 SYSC_writev fs/read_write.c:1017 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1014 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x445559 Fixes: b90e5794c5bd ("net: dont call jump_label_dec from irq context") Suggested-by: Cong Wang <xiyou.wangcong@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 5fa8bbda38c668e56b0c6cdecced2eac2fe36dec ]

Dmitry reported a warning [1] showing that we were calling
net_disable_timestamp() -> static_key_slow_dec() from a non
process context.

Grabbing a mutex while holding a spinlock or rcu_read_lock()
is not allowed.

As Cong suggested, we now use a work queue.

It is possible netstamp_clear() exits while netstamp_needed_deferred
is not zero, but it is probably not worth trying to do better than that.

netstamp_needed_deferred atomic tracks the exact number of deferred
decrements.

[1]
[ INFO: suspicious RCU usage. ]
4.10.0-rc5+ #192 Not tainted
-------------------------------
./include/linux/rcupdate.h:561 Illegal context switch in RCU read-side
critical section!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 0
2 locks held by syz-executor14/23111:
 #0:  (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff83a35c35>] lock_sock
include/net/sock.h:1454 [inline]
 #0:  (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff83a35c35>]
rawv6_sendmsg+0x1e65/0x3ec0 net/ipv6/raw.c:919
 #1:  (rcu_read_lock){......}, at: [<ffffffff83ae2678>] nf_hook
include/linux/netfilter.h:201 [inline]
 #1:  (rcu_read_lock){......}, at: [<ffffffff83ae2678>]
__ip6_local_out+0x258/0x840 net/ipv6/output_core.c:160

stack backtrace:
CPU: 2 PID: 23111 Comm: syz-executor14 Not tainted 4.10.0-rc5+ #192
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:15 [inline]
 dump_stack+0x2ee/0x3ef lib/dump_stack.c:51
 lockdep_rcu_suspicious+0x139/0x180 kernel/locking/lockdep.c:4452
 rcu_preempt_sleep_check include/linux/rcupdate.h:560 [inline]
 ___might_sleep+0x560/0x650 kernel/sched/core.c:7748
 __might_sleep+0x95/0x1a0 kernel/sched/core.c:7739
 mutex_lock_nested+0x24f/0x1730 kernel/locking/mutex.c:752
 atomic_dec_and_mutex_lock+0x119/0x160 kernel/locking/mutex.c:1060
 __static_key_slow_dec+0x7a/0x1e0 kernel/jump_label.c:149
 static_key_slow_dec+0x51/0x90 kernel/jump_label.c:174
 net_disable_timestamp+0x3b/0x50 net/core/dev.c:1728
 sock_disable_timestamp+0x98/0xc0 net/core/sock.c:403
 __sk_destruct+0x27d/0x6b0 net/core/sock.c:1441
 sk_destruct+0x47/0x80 net/core/sock.c:1460
 __sk_free+0x57/0x230 net/core/sock.c:1468
 sock_wfree+0xae/0x120 net/core/sock.c:1645
 skb_release_head_state+0xfc/0x200 net/core/skbuff.c:655
 skb_release_all+0x15/0x60 net/core/skbuff.c:668
 __kfree_skb+0x15/0x20 net/core/skbuff.c:684
 kfree_skb+0x16e/0x4c0 net/core/skbuff.c:705
 inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304
 inet_frag_put include/net/inet_frag.h:133 [inline]
 nf_ct_frag6_gather+0x1106/0x3840
net/ipv6/netfilter/nf_conntrack_reasm.c:617
 ipv6_defrag+0x1be/0x2b0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68
 nf_hook_entry_hookfn include/linux/netfilter.h:102 [inline]
 nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310
 nf_hook include/linux/netfilter.h:212 [inline]
 __ip6_local_out+0x489/0x840 net/ipv6/output_core.c:160
 ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170
 ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x2d1a/0x3ec0 net/ipv6/raw.c:927
 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
 sock_sendmsg_nosec net/socket.c:635 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:645
 sock_write_iter+0x326/0x600 net/socket.c:848
 do_iter_readv_writev+0x2e3/0x5b0 fs/read_write.c:695
 do_readv_writev+0x42c/0x9b0 fs/read_write.c:872
 vfs_writev+0x87/0xc0 fs/read_write.c:911
 do_writev+0x110/0x2c0 fs/read_write.c:944
 SYSC_writev fs/read_write.c:1017 [inline]
 SyS_writev+0x27/0x30 fs/read_write.c:1014
 entry_SYSCALL_64_fastpath+0x1f/0xc2
RIP: 0033:0x445559
RSP: 002b:00007f6f46fceb58 EFLAGS: 00000292 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000445559
RDX: 0000000000000001 RSI: 0000000020f1eff0 RDI: 0000000000000005
RBP: 00000000006e19c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000700000
R13: 0000000020f59000 R14: 0000000000000015 R15: 0000000000020400
BUG: sleeping function called from invalid context at
kernel/locking/mutex.c:752
in_atomic(): 1, irqs_disabled(): 0, pid: 23111, name: syz-executor14
INFO: lockdep is turned off.
CPU: 2 PID: 23111 Comm: syz-executor14 Not tainted 4.10.0-rc5+ #192
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:15 [inline]
 dump_stack+0x2ee/0x3ef lib/dump_stack.c:51
 ___might_sleep+0x47e/0x650 kernel/sched/core.c:7780
 __might_sleep+0x95/0x1a0 kernel/sched/core.c:7739
 mutex_lock_nested+0x24f/0x1730 kernel/locking/mutex.c:752
 atomic_dec_and_mutex_lock+0x119/0x160 kernel/locking/mutex.c:1060
 __static_key_slow_dec+0x7a/0x1e0 kernel/jump_label.c:149
 static_key_slow_dec+0x51/0x90 kernel/jump_label.c:174
 net_disable_timestamp+0x3b/0x50 net/core/dev.c:1728
 sock_disable_timestamp+0x98/0xc0 net/core/sock.c:403
 __sk_destruct+0x27d/0x6b0 net/core/sock.c:1441
 sk_destruct+0x47/0x80 net/core/sock.c:1460
 __sk_free+0x57/0x230 net/core/sock.c:1468
 sock_wfree+0xae/0x120 net/core/sock.c:1645
 skb_release_head_state+0xfc/0x200 net/core/skbuff.c:655
 skb_release_all+0x15/0x60 net/core/skbuff.c:668
 __kfree_skb+0x15/0x20 net/core/skbuff.c:684
 kfree_skb+0x16e/0x4c0 net/core/skbuff.c:705
 inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304
 inet_frag_put include/net/inet_frag.h:133 [inline]
 nf_ct_frag6_gather+0x1106/0x3840
net/ipv6/netfilter/nf_conntrack_reasm.c:617
 ipv6_defrag+0x1be/0x2b0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68
 nf_hook_entry_hookfn include/linux/netfilter.h:102 [inline]
 nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310
 nf_hook include/linux/netfilter.h:212 [inline]
 __ip6_local_out+0x489/0x840 net/ipv6/output_core.c:160
 ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170
 ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x2d1a/0x3ec0 net/ipv6/raw.c:927
 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744
 sock_sendmsg_nosec net/socket.c:635 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:645
 sock_write_iter+0x326/0x600 net/socket.c:848
 do_iter_readv_writev+0x2e3/0x5b0 fs/read_write.c:695
 do_readv_writev+0x42c/0x9b0 fs/read_write.c:872
 vfs_writev+0x87/0xc0 fs/read_write.c:911
 do_writev+0x110/0x2c0 fs/read_write.c:944
 SYSC_writev fs/read_write.c:1017 [inline]
 SyS_writev+0x27/0x30 fs/read_write.c:1014
 entry_SYSCALL_64_fastpath+0x1f/0xc2
RIP: 0033:0x445559

Fixes: b90e5794c5bd ("net: dont call jump_label_dec from irq context")
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net:Add sysctl_max_skb_frags 2017-02-08T08:43:05+00:00 Hans Westgaard Ry hans.westgaard.ry@oracle.com 2016-02-03T08:26:57+00:00 df93393787a3fc3b994c5061a890b0250bae0fbc commit 5f74f82ea34c0da80ea0b49192bb5ea06e063593 upstream. Devices may have limits on the number of fragments in an skb they support. Current codebase uses a constant as maximum for number of fragments one skb can hold and use. When enabling scatter/gather and running traffic with many small messages the codebase uses the maximum number of fragments and may thereby violate the max for certain devices. The patch introduces a global variable as max number of fragments. Signed-off-by: Hans Westgaard Ry <hans.westgaard.ry@oracle.com> Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5f74f82ea34c0da80ea0b49192bb5ea06e063593 upstream.

Devices may have limits on the number of fragments in an skb they support.
Current codebase uses a constant as maximum for number of fragments one
skb can hold and use.
When enabling scatter/gather and running traffic with many small messages
the codebase uses the maximum number of fragments and may thereby violate
the max for certain devices.
The patch introduces a global variable as max number of fragments.

Signed-off-by: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tunnels: Don't apply GRO to multiple layers of encapsulation. 2017-01-15T14:49:53+00:00 Jesse Gross jesse@kernel.org 2016-03-19T16:32:01+00:00 dd4fff23f0f4c7c5414f50c091c78a7e423f85da [ Upstream commit fac8e0f579695a3ecbc4d3cac369139d7f819971 ] When drivers express support for TSO of encapsulated packets, they only mean that they can do it for one layer of encapsulation. Supporting additional levels would mean updating, at a minimum, more IP length fields and they are unaware of this. No encapsulation device expresses support for handling offloaded encapsulated packets, so we won't generate these types of frames in the transmit path. However, GRO doesn't have a check for multiple levels of encapsulation and will attempt to build them. UDP tunnel GRO actually does prevent this situation but it only handles multiple UDP tunnels stacked on top of each other. This generalizes that solution to prevent any kind of tunnel stacking that would cause problems. Fixes: bf5a755f ("net-gre-gro: Add GRE support to the GRO stack") Signed-off-by: Jesse Gross <jesse@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> 
[ Upstream commit fac8e0f579695a3ecbc4d3cac369139d7f819971 ]

When drivers express support for TSO of encapsulated packets, they
only mean that they can do it for one layer of encapsulation.
Supporting additional levels would mean updating, at a minimum,
more IP length fields and they are unaware of this.

No encapsulation device expresses support for handling offloaded
encapsulated packets, so we won't generate these types of frames
in the transmit path. However, GRO doesn't have a check for
multiple levels of encapsulation and will attempt to build them.

UDP tunnel GRO actually does prevent this situation but it only
handles multiple UDP tunnels stacked on top of each other. This
generalizes that solution to prevent any kind of tunnel stacking
that would cause problems.

Fixes: bf5a755f ("net-gre-gro: Add GRE support to the GRO stack")
Signed-off-by: Jesse Gross <jesse@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
net: fix infoleak in rtnetlink 2016-07-12T12:48:14+00:00 Kangjie Lu kangjielu@gmail.com 2016-05-03T20:46:24+00:00 69243164a954a78073a83cb87d2e03254a4810ef [ Upstream commit 5f8e44741f9f216e33736ea4ec65ca9ac03036e6 ] The stack object “map” has a total size of 32 bytes. Its last 4 bytes are padding generated by compiler. These padding bytes are not initialized and sent out via “nla_put”. Signed-off-by: Kangjie Lu <kjlu@gatech.edu> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 
[ Upstream commit 5f8e44741f9f216e33736ea4ec65ca9ac03036e6 ]

The stack object “map” has a total size of 32 bytes. Its last 4
bytes are padding generated by compiler. These padding bytes are
not initialized and sent out via “nla_put”.

Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
net: Fix skb_set_peeked use-after-free bug 2016-04-12T12:47:23+00:00 Herbert Xu herbert@gondor.apana.org.au 2015-08-04T07:42:47+00:00 fae6f76ce1a42ed2f7f6ec1ba02e29602b0ebc16 [ Upstream commit a0a2a6602496a45ae838a96db8b8173794b5d398 ] The commit 738ac1ebb96d02e0d23bc320302a6ea94c612dec ("net: Clone skb before setting peeked flag") introduced a use-after-free bug in skb_recv_datagram. This is because skb_set_peeked may create a new skb and free the existing one. As it stands the caller will continue to use the old freed skb. This patch fixes it by making skb_set_peeked return the new skb (or the old one if unchanged). Fixes: 738ac1ebb96d ("net: Clone skb before setting peeked flag") Reported-by: Brenden Blanco <bblanco@plumgrid.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Tested-by: Brenden Blanco <bblanco@plumgrid.com> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 
[ Upstream commit a0a2a6602496a45ae838a96db8b8173794b5d398 ]

The commit 738ac1ebb96d02e0d23bc320302a6ea94c612dec ("net: Clone
skb before setting peeked flag") introduced a use-after-free bug
in skb_recv_datagram.  This is because skb_set_peeked may create
a new skb and free the existing one.  As it stands the caller will
continue to use the old freed skb.

This patch fixes it by making skb_set_peeked return the new skb
(or the old one if unchanged).

Fixes: 738ac1ebb96d ("net: Clone skb before setting peeked flag")
Reported-by: Brenden Blanco <bblanco@plumgrid.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Brenden Blanco <bblanco@plumgrid.com>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>