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Ivan Vecera 5cb1ebdbc4 ice: Fix race condition during interface enslave 
Commit 5dbbbd01cb ("ice: Avoid RTNL lock when re-creating
auxiliary device") changes a process of re-creation of aux device
so ice_plug_aux_dev() is called from ice_service_task() context.
This unfortunately opens a race window that can result in dead-lock
when interface has left LAG and immediately enters LAG again.

Reproducer:
```
#!/bin/sh

ip link add lag0 type bond mode 1 miimon 100
ip link set lag0

for n in {1..10}; do
        echo Cycle: $n
        ip link set ens7f0 master lag0
        sleep 1
        ip link set ens7f0 nomaster
done
```

This results in:
[20976.208697] Workqueue: ice ice_service_task [ice]
[20976.213422] Call Trace:
[20976.215871]  __schedule+0x2d1/0x830
[20976.219364]  schedule+0x35/0xa0
[20976.222510]  schedule_preempt_disabled+0xa/0x10
[20976.227043]  __mutex_lock.isra.7+0x310/0x420
[20976.235071]  enum_all_gids_of_dev_cb+0x1c/0x100 [ib_core]
[20976.251215]  ib_enum_roce_netdev+0xa4/0xe0 [ib_core]
[20976.256192]  ib_cache_setup_one+0x33/0xa0 [ib_core]
[20976.261079]  ib_register_device+0x40d/0x580 [ib_core]
[20976.266139]  irdma_ib_register_device+0x129/0x250 [irdma]
[20976.281409]  irdma_probe+0x2c1/0x360 [irdma]
[20976.285691]  auxiliary_bus_probe+0x45/0x70
[20976.289790]  really_probe+0x1f2/0x480
[20976.298509]  driver_probe_device+0x49/0xc0
[20976.302609]  bus_for_each_drv+0x79/0xc0
[20976.306448]  __device_attach+0xdc/0x160
[20976.310286]  bus_probe_device+0x9d/0xb0
[20976.314128]  device_add+0x43c/0x890
[20976.321287]  __auxiliary_device_add+0x43/0x60
[20976.325644]  ice_plug_aux_dev+0xb2/0x100 [ice]
[20976.330109]  ice_service_task+0xd0c/0xed0 [ice]
[20976.342591]  process_one_work+0x1a7/0x360
[20976.350536]  worker_thread+0x30/0x390
[20976.358128]  kthread+0x10a/0x120
[20976.365547]  ret_from_fork+0x1f/0x40
...
[20976.438030] task:ip              state:D stack:    0 pid:213658 ppid:213627 flags:0x00004084
[20976.446469] Call Trace:
[20976.448921]  __schedule+0x2d1/0x830
[20976.452414]  schedule+0x35/0xa0
[20976.455559]  schedule_preempt_disabled+0xa/0x10
[20976.460090]  __mutex_lock.isra.7+0x310/0x420
[20976.464364]  device_del+0x36/0x3c0
[20976.467772]  ice_unplug_aux_dev+0x1a/0x40 [ice]
[20976.472313]  ice_lag_event_handler+0x2a2/0x520 [ice]
[20976.477288]  notifier_call_chain+0x47/0x70
[20976.481386]  __netdev_upper_dev_link+0x18b/0x280
[20976.489845]  bond_enslave+0xe05/0x1790 [bonding]
[20976.494475]  do_setlink+0x336/0xf50
[20976.502517]  __rtnl_newlink+0x529/0x8b0
[20976.543441]  rtnl_newlink+0x43/0x60
[20976.546934]  rtnetlink_rcv_msg+0x2b1/0x360
[20976.559238]  netlink_rcv_skb+0x4c/0x120
[20976.563079]  netlink_unicast+0x196/0x230
[20976.567005]  netlink_sendmsg+0x204/0x3d0
[20976.570930]  sock_sendmsg+0x4c/0x50
[20976.574423]  ____sys_sendmsg+0x1eb/0x250
[20976.586807]  ___sys_sendmsg+0x7c/0xc0
[20976.606353]  __sys_sendmsg+0x57/0xa0
[20976.609930]  do_syscall_64+0x5b/0x1a0
[20976.613598]  entry_SYSCALL_64_after_hwframe+0x65/0xca

1. Command 'ip link ... set nomaster' causes that ice_plug_aux_dev()
   is called from ice_service_task() context, aux device is created
   and associated device->lock is taken.
2. Command 'ip link ... set master...' calls ice's notifier under
   RTNL lock and that notifier calls ice_unplug_aux_dev(). That
   function tries to take aux device->lock but this is already taken
   by ice_plug_aux_dev() in step 1
3. Later ice_plug_aux_dev() tries to take RTNL lock but this is already
   taken in step 2
4. Dead-lock

The patch fixes this issue by following changes:
- Bit ICE_FLAG_PLUG_AUX_DEV is kept to be set during ice_plug_aux_dev()
  call in ice_service_task()
- The bit is checked in ice_clear_rdma_cap() and only if it is not set
  then ice_unplug_aux_dev() is called. If it is set (in other words
  plugging of aux device was requested and ice_plug_aux_dev() is
  potentially running) then the function only clears the bit
- Once ice_plug_aux_dev() call (in ice_service_task) is finished
  the bit ICE_FLAG_PLUG_AUX_DEV is cleared but it is also checked
  whether it was already cleared by ice_clear_rdma_cap(). If so then
  aux device is unplugged.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Co-developed-by: Petr Oros <poros@redhat.com>
Signed-off-by: Petr Oros <poros@redhat.com>
Reviewed-by: Dave Ertman <david.m.ertman@intel.com>
Link: https://lore.kernel.org/r/20220310171641.3863659-1-ivecera@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-10 15:07:46 -08:00
arch - Fix memory detection for MT7621 devices 2022-03-03 10:38:28 -08:00
block block: clear iocb->private in blkdev_bio_end_io_async() 2022-02-22 06:59:49 -07:00
certs certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty 2022-01-23 00:08:44 +09:00
crypto crypto: af_alg - get rid of alg_memory_allocated 2022-02-15 14:29:04 +00:00
Documentation ARM: SoC fixes for v5.17, part 2 2022-02-28 12:51:14 -08:00
drivers ice: Fix race condition during interface enslave 2022-03-10 15:07:46 -08:00
fs Change since last update: 2022-03-02 12:08:36 -08:00
include net: phy: correct spelling error of media in documentation 2022-03-10 14:40:59 -08:00
init lib/stackdepot: allow optional init and stack_table allocation by kvmalloc() 2022-01-22 08:33:37 +02:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-04 09:25:05 -08:00
kernel Merge branch 'ucount-rlimit-fixes-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2022-03-02 16:20:04 -08:00
lib ARM further fixes for 5.17-rc: 2022-03-02 16:11:56 -08:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm memblock: use kfree() to release kmalloced memblock regions 2022-02-26 12:00:44 -08:00
net sctp: fix kernel-infoleak for SCTP sockets 2022-03-10 14:46:42 -08:00
samples samples/seccomp: Adjust sample to also provide kill option 2022-02-10 19:09:12 -08:00
scripts kconfig: fix failing to generate auto.conf 2022-02-12 23:24:19 +09:00
security selinux/stable-5.17 PR 20220223 2022-02-23 17:19:55 -08:00
sound ASoC: intel: skylake: Set max DMA segment size 2022-02-17 09:39:44 +01:00
tools selftests: pmtu.sh: Kill nettest processes launched in subshell. 2022-03-09 20:23:32 -08:00
usr kbuild: remove include/linux/cyclades.h from header file check 2022-01-27 08:51:08 +01:00
virt KVM: Fix lockdep false negative during host resume 2022-02-17 09:52:50 -05:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update Roman Gushchin's email 2022-02-26 09:51:17 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Bug fixes for sparse warning, intel port config offset, and a new 2022-03-02 11:58:27 -08:00
Makefile Linux 5.17-rc6 2022-02-27 14:36:33 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.