Eric Dumazet 11fa335320 tcp/dccp: fix other lockdep splats accessing ireq_opt ... [ Upstream commit 06f877d613 ] In my first attempt to fix the lockdep splat, I forgot we could enter inet_csk_route_req() with a freshly allocated request socket, for which refcount has not yet been elevated, due to complex SLAB_TYPESAFE_BY_RCU rules. We either are in rcu_read_lock() section _or_ we own a refcount on the request. Correct RCU verb to use here is rcu_dereference_check(), although it is not possible to prove we actually own a reference on a shared refcount :/ In v2, I added ireq_opt_deref() helper and use in three places, to fix other possible splats. [ 49.844590] lockdep_rcu_suspicious+0xea/0xf3 [ 49.846487] inet_csk_route_req+0x53/0x14d [ 49.848334] tcp_v4_route_req+0xe/0x10 [ 49.850174] tcp_conn_request+0x31c/0x6a0 [ 49.851992] ? __lock_acquire+0x614/0x822 [ 49.854015] tcp_v4_conn_request+0x5a/0x79 [ 49.855957] ? tcp_v4_conn_request+0x5a/0x79 [ 49.858052] tcp_rcv_state_process+0x98/0xdcc [ 49.859990] ? sk_filter_trim_cap+0x2f6/0x307 [ 49.862085] tcp_v4_do_rcv+0xfc/0x145 [ 49.864055] ? tcp_v4_do_rcv+0xfc/0x145 [ 49.866173] tcp_v4_rcv+0x5ab/0xaf9 [ 49.868029] ip_local_deliver_finish+0x1af/0x2e7 [ 49.870064] ip_local_deliver+0x1b2/0x1c5 [ 49.871775] ? inet_del_offload+0x45/0x45 [ 49.873916] ip_rcv_finish+0x3f7/0x471 [ 49.875476] ip_rcv+0x3f1/0x42f [ 49.876991] ? ip_local_deliver_finish+0x2e7/0x2e7 [ 49.878791] __netif_receive_skb_core+0x6d3/0x950 [ 49.880701] ? process_backlog+0x7e/0x216 [ 49.882589] __netif_receive_skb+0x1d/0x5e [ 49.884122] process_backlog+0x10c/0x216 [ 49.885812] net_rx_action+0x147/0x3df Fixes: a6ca7abe53 ("tcp/dccp: fix lockdep splat in inet_csk_route_req()") Fixes: c92e8c02fe ("tcp/dccp: fix ireq->opt races") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: kernel test robot <fengguang.wu@intel.com> Reported-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-11-18 11:11:07 +01:00
..
acpi	Merge branch 'acpi-pci'	2015-11-07 01:30:10 +01:00
asm-generic	percpu: make this_cpu_generic_read() atomic w.r.t. interrupts	2017-10-21 17:09:01 +02:00
clocksource
crypto	crypto: ahash - Fix EINPROGRESS notification callback	2017-04-21 09:30:06 +02:00
drm	drm/ttm, drm/vmwgfx: Relax permission checking when opening surfaces	2017-04-12 12:38:33 +02:00
dt-bindings	ARM: DT updates for v4.4	2015-11-10 15:06:26 -08:00
keys
kvm	KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active	2015-11-24 18:07:40 +01:00
linux	tun: call dev_get_valid_name() before register_netdevice()	2017-11-18 11:11:05 +01:00
math-emu
media	videobuf2-core: Check user space planes array in dqbuf	2016-05-04 14:48:50 -07:00
memory
misc
net	tcp/dccp: fix other lockdep splats accessing ireq_opt	2017-11-18 11:11:07 +01:00
pcmcia
ras
rdma	RDMA/core: Fix incorrect structure packing for booleans	2017-03-12 06:37:29 +01:00
rxrpc
scsi	scsi: libiscsi: add lock around task lists to fix list corruption regression	2017-03-26 12:13:19 +02:00
soc	ARM: at91: define LPDDR types	2017-03-12 06:37:24 +01:00
sound	ALSA: seq: Avoid invalid lockdep class warning	2017-11-15 17:13:12 +01:00
target	iscsi-target: Fix iscsi_np reset hung task during parallel delete	2017-08-16 13:40:28 -07:00
trace	tracing: Add #undef to fix compile error	2017-03-18 19:09:57 +08:00
uapi	spi: uapi: spidev: add missing ioctl header	2017-11-02 09:40:49 +01:00
video	drm/imx: Match imx-ipuv3-crtc components using device node in platform data	2016-06-07 18:14:37 -07:00
xen	fix xen_swiotlb_dma_mmap prototype	2017-10-05 09:41:48 +02:00
Kbuild