linux/include
Martin Willi 8dc08a2962 can: dev: Move device back to init netns on owning netns delete
commit 3a5ca85707 upstream.

When a non-initial netns is destroyed, the usual policy is to delete
all virtual network interfaces contained, but move physical interfaces
back to the initial netns. This keeps the physical interface visible
on the system.

CAN devices are somewhat special, as they define rtnl_link_ops even
if they are physical devices. If a CAN interface is moved into a
non-initial netns, destroying that netns lets the interface vanish
instead of moving it back to the initial netns. default_device_exit()
skips CAN interfaces due to having rtnl_link_ops set. Reproducer:

  ip netns add foo
  ip link set can0 netns foo
  ip netns delete foo

WARNING: CPU: 1 PID: 84 at net/core/dev.c:11030 ops_exit_list+0x38/0x60
CPU: 1 PID: 84 Comm: kworker/u4:2 Not tainted 5.10.19 #1
Workqueue: netns cleanup_net
[<c010e700>] (unwind_backtrace) from [<c010a1d8>] (show_stack+0x10/0x14)
[<c010a1d8>] (show_stack) from [<c086dc10>] (dump_stack+0x94/0xa8)
[<c086dc10>] (dump_stack) from [<c086b938>] (__warn+0xb8/0x114)
[<c086b938>] (__warn) from [<c086ba10>] (warn_slowpath_fmt+0x7c/0xac)
[<c086ba10>] (warn_slowpath_fmt) from [<c0629f20>] (ops_exit_list+0x38/0x60)
[<c0629f20>] (ops_exit_list) from [<c062a5c4>] (cleanup_net+0x230/0x380)
[<c062a5c4>] (cleanup_net) from [<c0142c20>] (process_one_work+0x1d8/0x438)
[<c0142c20>] (process_one_work) from [<c0142ee4>] (worker_thread+0x64/0x5a8)
[<c0142ee4>] (worker_thread) from [<c0148a98>] (kthread+0x148/0x14c)
[<c0148a98>] (kthread) from [<c0100148>] (ret_from_fork+0x14/0x2c)

To properly restore physical CAN devices to the initial netns on owning
netns exit, introduce a flag on rtnl_link_ops that can be set by drivers.
For CAN devices setting this flag, default_device_exit() considers them
non-virtual, applying the usual namespace move.

The issue was introduced in the commit mentioned below, as at that time
CAN devices did not have a dellink() operation.

Fixes: e008b5fc8d ("net: Simplfy default_device_exit and improve batching.")
Link: https://lore.kernel.org/r/20210302122423.872326-1-martin@strongswan.org
Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-30 14:32:08 +02:00
..
acpi ACPI: scan: Use unique number for instance_no 2021-03-30 14:32:06 +02:00
asm-generic static_call: Allow module use without exposing static_call_key 2021-03-30 14:31:53 +02:00
clocksource
crypto crypto - shash: reduce minimum alignment of shash_desc structure 2021-03-09 11:11:13 +01:00
drm drm/dp/mst: Export drm_dp_get_vc_payload_bw() 2021-02-10 09:29:18 +01:00
dt-bindings ASoC: dt-bindings: lpass: Fix and common up lpass dai ids 2021-02-03 23:28:46 +01:00
keys
kunit kunit: fix display of failed expectations for strings 2020-11-10 13:45:15 -07:00
kvm ARM: 2020-10-23 11:17:56 -07:00
linux fs/cachefiles: Remove wait_bit_key layout dependency 2021-03-30 14:32:07 +02:00
math-emu
media media: rc: compile rc-cec.c into rc-core 2021-03-17 17:06:20 +01:00
memory
misc
net can: dev: Move device back to init netns on owning netns delete 2021-03-30 14:32:08 +02:00
pcmcia
ras
rdma RDMA: Lift ibdev_to_node from rds to common code 2021-02-26 10:12:59 +01:00
scsi scsi: libsas: Introduce a _gfp() variant of event notifiers 2021-03-25 09:04:11 +01:00
soc net: dsa: felix: implement port flushing on .phylink_mac_link_down 2021-02-17 11:02:27 +01:00
sound ALSA: hda: intel-nhlt: verify config type 2021-03-09 11:11:14 +01:00
target scsi: target: core: Add cmd length set before cmd complete 2021-03-17 17:06:25 +01:00
trace trace: fix potenial dangerous pointer 2020-11-25 13:03:44 +01:00
uapi psample: Fix user API breakage 2021-03-30 14:31:53 +02:00
vdso
video gpu: ipu-v3: remove unused functions 2020-10-26 10:42:38 +01:00
xen Xen/gntdev: correct error checking in gntdev_map_grant_pages() 2021-02-23 15:53:24 +01:00