John Fastabend bbbe211c29 net: rcu lock and preempt disable missing around generic xdp ... do_xdp_generic must be called inside rcu critical section with preempt disabled to ensure BPF programs are valid and per-cpu variables used for redirect operations are consistent. This patch ensures this is true and fixes the splat below. The netif_receive_skb_internal() code path is now broken into two rcu critical sections. I decided it was better to limit the preempt_enable/disable block to just the xdp static key portion and the fallout is more rcu_read_lock/unlock calls. Seems like the best option to me. [ 607.596901] ============================= [ 607.596906] WARNING: suspicious RCU usage [ 607.596912] 4.13.0-rc4+ #570 Not tainted [ 607.596917] ----------------------------- [ 607.596923] net/core/dev.c:3948 suspicious rcu_dereference_check() usage! [ 607.596927] [ 607.596927] other info that might help us debug this: [ 607.596927] [ 607.596933] [ 607.596933] rcu_scheduler_active = 2, debug_locks = 1 [ 607.596938] 2 locks held by pool/14624: [ 607.596943] #0: (rcu_read_lock_bh){......}, at: [<ffffffff95445ffd>] ip_finish_output2+0x14d/0x890 [ 607.596973] #1: (rcu_read_lock_bh){......}, at: [<ffffffff953c8e3a>] __dev_queue_xmit+0x14a/0xfd0 [ 607.597000] [ 607.597000] stack backtrace: [ 607.597006] CPU: 5 PID: 14624 Comm: pool Not tainted 4.13.0-rc4+ #570 [ 607.597011] Hardware name: Dell Inc. Precision Tower 5810/0HHV7N, BIOS A17 03/01/2017 [ 607.597016] Call Trace: [ 607.597027] dump_stack+0x67/0x92 [ 607.597040] lockdep_rcu_suspicious+0xdd/0x110 [ 607.597054] do_xdp_generic+0x313/0xa50 [ 607.597068] ? time_hardirqs_on+0x5b/0x150 [ 607.597076] ? mark_held_locks+0x6b/0xc0 [ 607.597088] ? netdev_pick_tx+0x150/0x150 [ 607.597117] netif_rx_internal+0x205/0x3f0 [ 607.597127] ? do_xdp_generic+0xa50/0xa50 [ 607.597144] ? lock_downgrade+0x2b0/0x2b0 [ 607.597158] ? __lock_is_held+0x93/0x100 [ 607.597187] netif_rx+0x119/0x190 [ 607.597202] loopback_xmit+0xfd/0x1b0 [ 607.597214] dev_hard_start_xmit+0x127/0x4e0 Fixes: d445516966 ("net: xdp: support xdp generic on virtual devices") Fixes: b5cdae3291 ("net: Generic XDP") Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-09-08 21:11:00 -07:00
..
datagram.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2017-09-01 17:42:05 -07:00
dev_addr_lists.c
dev_ioctl.c	net: check dev->addr_len for dev_set_mac_address()	2017-07-29 11:25:05 -07:00
dev.c	net: rcu lock and preempt disable missing around generic xdp	2017-09-08 21:11:00 -07:00
devlink.c	devlink: Add IPv6 header for dpipe	2017-08-31 14:42:19 -07:00
drop_monitor.c	drop_monitor: use setup_timer	2017-03-12 23:47:16 -07:00
dst_cache.c	net: dst_cache_per_cpu_dst_set() can be static	2016-03-18 17:45:08 -04:00
dst.c	net: check type when freeing metadata dst	2017-08-21 10:57:38 -07:00
ethtool.c	net: ethtool: add support for forward error correction modes	2017-07-29 23:23:44 -07:00
fib_notifier.c	net: Add module reference to FIB notifiers	2017-09-01 20:33:42 -07:00
fib_rules.c	rtnetlink: make rtnl_register accept a flags parameter	2017-08-09 16:57:38 -07:00
filter.c	bpf: don't select potentially stale ri->map from buggy xdp progs	2017-09-08 20:58:09 -07:00
flow_dissector.c	flow_dissector: Add limit for number of headers to dissect	2017-09-05 11:40:08 -07:00
gen_estimator.c	Replace <asm/uaccess.h> with <linux/uaccess.h> globally	2016-12-24 11:46:01 -08:00
gen_stats.c	net_sched: gen_estimator: complete rewrite of rate estimators	2016-12-05 15:21:59 -05:00
gro_cells.c	net: Generic XDP	2017-04-25 13:33:49 -04:00
hwbm.c	net: hwbm: Fix unbalanced spinlock in error case	2016-05-25 12:35:09 -07:00
link_watch.c
lwt_bpf.c	net: add extack arg to lwtunnel build state	2017-05-30 11:55:32 -04:00
lwtunnel.c	ipv6: sr: define core operations for seg6local lightweight tunnel	2017-08-07 14:16:22 -07:00
Makefile	net: core: Make the FIB notification chain generic	2017-08-03 15:35:59 -07:00
neighbour.c	rtnetlink: make rtnl_register accept a flags parameter	2017-08-09 16:57:38 -07:00
net_namespace.c	net: call newid/getid without rtnl mutex held	2017-08-09 16:57:38 -07:00
net-procfs.c	net-procfs: Use vsnprintf extension %phN	2017-06-04 19:52:58 -04:00
net-sysfs.c	net: style cleanups	2017-08-18 22:38:47 -07:00
net-sysfs.h
net-traces.c	bridge: add tracepoint in br_fdb_update	2017-08-31 11:42:41 -07:00
netclassid_cgroup.c	cgroup, net_cls: iterate the fds of only the tasks which are being migrated	2017-03-22 10:32:46 -07:00
netevent.c
netpoll.c	netpoll: Fix device name check in netpoll_setup()	2017-07-26 17:01:43 -07:00
netprio_cgroup.c	net: break include loop netdevice.h, dsa.h, devlink.h	2017-03-28 22:46:04 -07:00
pktgen.c	net: convert sk_buff.users from atomic_t to refcount_t	2017-07-01 07:39:07 -07:00
ptp_classifier.c
request_sock.c	ipv4: Namespaceify tcp_max_syn_backlog knob	2016-12-29 11:38:31 -05:00
rtnetlink.c	rtnelink: Move link dump consistency check out of the loop	2017-08-13 19:43:57 -07:00
scm.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h>	2017-03-02 08:42:29 +01:00
secure_seq.c	tcp: Namespaceify sysctl_tcp_timestamps	2017-06-08 10:53:29 -04:00
skbuff.c	udp: drop head states only when all skb references are gone	2017-09-07 20:02:39 -07:00
sock_diag.c	netlink: extended ACK reporting	2017-04-13 13:58:20 -04:00
sock_reuseport.c	soreuseport: use "unsigned int" in __reuseport_alloc()	2017-04-03 19:06:38 -07:00
sock.c	neigh: increase queue_len_bytes to match wmem_default	2017-08-29 16:10:50 -07:00
stream.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>	2017-03-02 08:42:29 +01:00
sysctl_net_core.c	net: move somaxconn init from sysctl code	2017-05-25 13:12:17 -04:00
timestamping.c
tso.c
utils.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2017-05-02 16:40:27 -07:00