android_kernel_oneplus_msm8998/include
Dan Streetman edaafa805e net: tcp: close sock if net namespace is exiting
[ Upstream commit 4ee806d51176ba7b8ff1efd81f271d7252e03a1d ]

When a tcp socket is closed, if it detects that its net namespace is
exiting, close immediately and do not wait for FIN sequence.

For normal sockets, a reference is taken to their net namespace, so it will
never exit while the socket is open.  However, kernel sockets do not take a
reference to their net namespace, so it may begin exiting while the kernel
socket is still open.  In this case if the kernel socket is a tcp socket,
it will stay open trying to complete its close sequence.  The sock's dst(s)
hold a reference to their interface, which are all transferred to the
namespace's loopback interface when the real interfaces are taken down.
When the namespace tries to take down its loopback interface, it hangs
waiting for all references to the loopback interface to release, which
results in messages like:

unregister_netdevice: waiting for lo to become free. Usage count = 1

These messages continue until the socket finally times out and closes.
Since the net namespace cleanup holds the net_mutex while calling its
registered pernet callbacks, any new net namespace initialization is
blocked until the current net namespace finishes exiting.

After this change, the tcp socket notices the exiting net namespace, and
closes immediately, releasing its dst(s) and their reference to the
loopback interface, which lets the net namespace continue exiting.

Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=97811
Signed-off-by: Dan Streetman <ddstreet@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-31 12:06:14 +01:00
..
acpi Merge branch 'acpi-pci' 2015-11-07 01:30:10 +01:00
asm-generic EXPORT_SYMBOL() for asm 2018-01-23 19:50:12 +01:00
clocksource
crypto crypto: mcryptd - protect the per-CPU queue with a lock 2018-01-02 20:33:19 +01:00
drm drm: extra printk() wrapper macros 2017-12-16 10:33:49 +01:00
dt-bindings ARM: dts: Fix omap3 off mode pull defines 2017-11-21 09:21:19 +01:00
keys KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00
kvm KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active 2015-11-24 18:07:40 +01:00
linux tcp: __tcp_hdrlen() helper 2018-01-31 12:06:13 +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 net: tcp: close sock if net namespace is exiting 2018-01-31 12:06:14 +01:00
pcmcia
ras
rdma RDMA/core: Fix incorrect structure packing for booleans 2017-03-12 06:37:29 +01:00
rxrpc
scsi scsi: sg: disable SET_FORCE_LOW_DMA 2018-01-23 19:50:14 +01:00
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 target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK 2018-01-17 09:35:31 +01:00
trace KVM: Fix stack-out-of-bounds read in write_mmio 2018-01-17 09:35:24 +01:00
uapi eventpoll.h: add missing epoll event masks 2018-01-31 12:06:12 +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