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Stanislav Fomichev 299d7d27af net: vlan: don't propagate flags on open
[ Upstream commit 27b918007d ]

With the device instance lock, there is now a possibility of a deadlock:

[    1.211455] ============================================
[    1.211571] WARNING: possible recursive locking detected
[    1.211687] 6.14.0-rc5-01215-g032756b4ca7a-dirty #5 Not tainted
[    1.211823] --------------------------------------------
[    1.211936] ip/184 is trying to acquire lock:
[    1.212032] ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_set_allmulti+0x4e/0xb0
[    1.212207]
[    1.212207] but task is already holding lock:
[    1.212332] ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x50/0xb0
[    1.212487]
[    1.212487] other info that might help us debug this:
[    1.212626]  Possible unsafe locking scenario:
[    1.212626]
[    1.212751]        CPU0
[    1.212815]        ----
[    1.212871]   lock(&dev->lock);
[    1.212944]   lock(&dev->lock);
[    1.213016]
[    1.213016]  *** DEADLOCK ***
[    1.213016]
[    1.213143]  May be due to missing lock nesting notation
[    1.213143]
[    1.213294] 3 locks held by ip/184:
[    1.213371]  #0: ffffffff838b53e0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock+0x1b/0xa0
[    1.213543]  #1: ffffffff84e5fc70 (&net->rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock+0x37/0xa0
[    1.213727]  #2: ffff8881024a4c30 (&dev->lock){+.+.}-{4:4}, at: dev_open+0x50/0xb0
[    1.213895]
[    1.213895] stack backtrace:
[    1.213991] CPU: 0 UID: 0 PID: 184 Comm: ip Not tainted 6.14.0-rc5-01215-g032756b4ca7a-dirty #5
[    1.213993] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[    1.213994] Call Trace:
[    1.213995]  <TASK>
[    1.213996]  dump_stack_lvl+0x8e/0xd0
[    1.214000]  print_deadlock_bug+0x28b/0x2a0
[    1.214020]  lock_acquire+0xea/0x2a0
[    1.214027]  __mutex_lock+0xbf/0xd40
[    1.214038]  dev_set_allmulti+0x4e/0xb0 # real_dev->flags & IFF_ALLMULTI
[    1.214040]  vlan_dev_open+0xa5/0x170 # ndo_open on vlandev
[    1.214042]  __dev_open+0x145/0x270
[    1.214046]  __dev_change_flags+0xb0/0x1e0
[    1.214051]  netif_change_flags+0x22/0x60 # IFF_UP vlandev
[    1.214053]  dev_change_flags+0x61/0xb0 # for each device in group from dev->vlan_info
[    1.214055]  vlan_device_event+0x766/0x7c0 # on netdevsim0
[    1.214058]  notifier_call_chain+0x78/0x120
[    1.214062]  netif_open+0x6d/0x90
[    1.214064]  dev_open+0x5b/0xb0 # locks netdevsim0
[    1.214066]  bond_enslave+0x64c/0x1230
[    1.214075]  do_set_master+0x175/0x1e0 # on netdevsim0
[    1.214077]  do_setlink+0x516/0x13b0
[    1.214094]  rtnl_newlink+0xaba/0xb80
[    1.214132]  rtnetlink_rcv_msg+0x440/0x490
[    1.214144]  netlink_rcv_skb+0xeb/0x120
[    1.214150]  netlink_unicast+0x1f9/0x320
[    1.214153]  netlink_sendmsg+0x346/0x3f0
[    1.214157]  __sock_sendmsg+0x86/0xb0
[    1.214160]  ____sys_sendmsg+0x1c8/0x220
[    1.214164]  ___sys_sendmsg+0x28f/0x2d0
[    1.214179]  __x64_sys_sendmsg+0xef/0x140
[    1.214184]  do_syscall_64+0xec/0x1d0
[    1.214190]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[    1.214191] RIP: 0033:0x7f2d1b4a7e56

Device setup:

     netdevsim0 (down)
     ^        ^
  bond        netdevsim1.100@netdevsim1 allmulticast=on (down)

When we enslave the lower device (netdevsim0) which has a vlan, we
propagate vlan's allmuti/promisc flags during ndo_open. This causes
(re)locking on of the real_dev.

Propagate allmulti/promisc on flags change, not on the open. There
is a slight semantics change that vlans that are down now propagate
the flags, but this seems unlikely to result in the real issues.

Reproducer:

  echo 0 1 > /sys/bus/netdevsim/new_device

  dev_path=$(ls -d /sys/bus/netdevsim/devices/netdevsim0/net/*)
  dev=$(echo $dev_path | rev | cut -d/ -f1 | rev)

  ip link set dev $dev name netdevsim0
  ip link set dev netdevsim0 up

  ip link add link netdevsim0 name netdevsim0.100 type vlan id 100
  ip link set dev netdevsim0.100 allmulticast on down
  ip link add name bond1 type bond mode 802.3ad
  ip link set dev netdevsim0 down
  ip link set dev netdevsim0 master bond1
  ip link set dev bond1 up
  ip link show

Reported-by: syzbot+b0c03d76056ef6cd12a6@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/Z9CfXjLMKn6VLG5d@mini-arch/T/#m15ba130f53227c883e79fb969687d69d670337a0
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250313100657.2287455-1-sdf@fomichev.me
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-04-20 10:15:21 +02:00
arch arm64: cputype: Add QCOM_CPU_PART_KRYO_3XX_GOLD 2025-04-20 10:15:12 +02:00
block block: fix 'kmem_cache of name 'bio-108' already exists' 2025-03-22 12:54:21 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Fix larval relookup type and mask 2025-04-10 14:39:20 +02:00
Documentation ata: libata-core: Add 'external' to the libata.force kernel parameter 2025-04-20 10:15:16 +02:00
drivers wifi: mt76: mt76x2u: add TP-Link TL-WDN6200 ID to device table 2025-04-20 10:15:21 +02:00
fs btrfs: harden block_group::bg_list against list_del() races 2025-04-20 10:15:21 +02:00
include wifi: mac80211: add strict mode disabling workarounds 2025-04-20 10:15:17 +02:00
init ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE 2025-04-10 14:39:40 +02:00
io_uring io_uring/net: fix sendzc double notif flush 2025-03-28 22:03:32 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel Flush console log from kernel_power_off() 2025-04-20 10:15:12 +02:00
lib zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work around compiler segfault 2025-04-20 10:15:12 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: zswap: fix crypto_free_acomp() deadlock in zswap_cpu_comp_dead() 2025-04-10 14:39:40 +02:00
net net: vlan: don't propagate flags on open 2025-04-20 10:15:21 +02:00
rust rust: Fix enabling Rust and building with GCC for LoongArch 2025-04-10 14:39:36 +02:00
samples rust: treewide: switch to the kernel Vec type 2025-03-13 13:01:46 +01:00
scripts kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally 2025-04-10 14:39:35 +02:00
security smack: ipv4/ipv6: tcp/dccp/sctp: fix incorrect child socket label 2025-04-10 14:39:10 +02:00
sound ASoC: amd: yc: update quirk data for new Lenovo model 2025-04-20 10:15:15 +02:00
tools pm: cpupower: bench: Prevent NULL dereference on malloc failure 2025-04-20 10:15:10 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: enable Clippy's check-private-items 2025-03-13 13:01:42 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add entry for the Rust alloc module 2025-03-13 13:01:47 +01:00
Makefile Linux 6.12.23 2025-04-10 14:39:41 +02:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText 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.