linux_dsm_epyc7002/include
Dan Streetman 4ee806d511 net: tcp: close sock if net namespace is exiting
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>
2018-01-25 10:56:45 -05:00
..
acpi Merge branch 'acpi-ec' into acpi 2017-11-30 13:37:29 +01:00
asm-generic Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-23 11:53:04 -08:00
clocksource arm64 updates for 4.15 2017-11-15 10:56:56 -08:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-01-05 12:10:06 -08:00
drm drm: rework delayed connector cleanup in connector_iter 2017-12-13 22:59:00 +01:00
dt-bindings fixes/cleanups for rc1, non-desktop flags for VR 2017-11-23 21:04:56 -10:00
keys
kvm KVM: arm/arm64: timer: Don't set irq as forwarded if no usable GIC 2017-12-18 10:53:23 +01:00
linux With the new ORC unwinder, ftrace stack tracing became disfunctional. 2018-01-24 10:08:16 -08:00
math-emu
media media updates for v4.15-rc1 2017-11-15 20:30:12 -08:00
memory
misc
net net: tcp: close sock if net namespace is exiting 2018-01-25 10:56:45 -05:00
pcmcia
ras
rdma Updates for 4.15 kernel merge window 2017-11-15 14:54:53 -08:00
scsi scsi: libsas: align sata_device's rps_resp on a cacheline 2017-11-21 23:06:32 -05:00
soc We have two changes to the core framework this time around. The first being a 2017-11-17 20:04:24 -08:00
sound ALSA: hda - Fix yet remaining issue with vmaster 0dB initialization 2017-11-22 12:34:56 +01:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-11-24 19:19:20 -10:00
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-12-28 23:20:21 -08:00
uapi KVM fixes for v4.15-rc9 2018-01-20 11:41:09 -08:00
video fbdev changes for v4.15: 2017-11-20 21:50:24 -10:00
xen xen: fixes for 4.15-rc5 2017-12-22 12:30:10 -08:00