Re: [PATCH net-next v2 2/2] Create netdev->neighbour association

[kernel test robot <oliver.sang@intel.com>]

Hello,

kernel test robot noticed "WARNING:suspicious_RCU_usage" on:

commit: a64ba5de5ee501e1027b1b3bc0cf3a80047cfa05 ("[PATCH net-next v2 2/2] Create netdev->neighbour association")
url: https://github.com/intel-lab-lkp/linux/commits/Gilad-Naaman/Convert-neighbour-table-to-use-hlist/20241006-145017
base: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git 8f602276d3902642fdc3429b548d73c745446601
patch link: https://lore.kernel.org/all/20241006064747.201773-3-gnaaman@drivenets.com/
patch subject: [PATCH net-next v2 2/2] Create netdev->neighbour association

in testcase: rcutorture
version: 
with following parameters:

	runtime: 300s
	test: default
	torture_type: trivial



compiler: gcc-12
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

(please refer to attached dmesg/kmsg for entire log/backtrace)


+---------------------------------------------------------------+------------+------------+
|                                                               | febd2a80c4 | a64ba5de5e |
+---------------------------------------------------------------+------------+------------+
| WARNING:suspicious_RCU_usage                                  | 0          | 6          |
| net/core/neighbour.c:#suspicious_rcu_dereference_check()usage | 0          | 6          |
+---------------------------------------------------------------+------------+------------+


If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202410091223.b011d2e6-lkp@intel.com


[    7.752029][    T1] WARNING: suspicious RCU usage
[    7.752608][    T1] 6.12.0-rc1-00351-ga64ba5de5ee5 #1 Not tainted
[    7.753375][    T1] -----------------------------
[    7.753944][    T1] net/core/neighbour.c:427 suspicious rcu_dereference_check() usage!
[    7.754874][    T1]
[    7.754874][    T1] other info that might help us debug this:
[    7.754874][    T1]
[    7.756040][    T1]
[    7.756040][    T1] rcu_scheduler_active = 2, debug_locks = 1
[    7.756973][    T1] 3 locks held by swapper/1:
[ 7.757526][ T1] #0: 4271c954 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock (net/core/rtnetlink.c:80) 
[ 7.758448][ T1] #1: 4272abf8 ((inetaddr_chain).rwsem){++++}-{3:3}, at: blocking_notifier_call_chain (kernel/notifier.c:388 kernel/notifier.c:376) 
[ 7.759702][ T1] #2: 4272a180 (&tbl->lock){+...}-{2:2}, at: __neigh_ifdown+0x1d/0x108 
[    7.760778][    T1]
[    7.760778][    T1] stack backtrace:
[    7.761508][    T1] CPU: 0 UID: 0 PID: 1 Comm: swapper Not tainted 6.12.0-rc1-00351-ga64ba5de5ee5 #1
[    7.762586][    T1] Call Trace:
[ 7.762968][ T1] ? dump_stack_lvl (lib/dump_stack.c:123 (discriminator 1)) 
[ 7.763512][ T1] ? dump_stack (lib/dump_stack.c:130) 
[ 7.764002][ T1] ? lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822) 
[ 7.764645][ T1] ? neigh_flush_dev (net/core/neighbour.c:427 (discriminator 9)) 
[ 7.765201][ T1] ? _raw_write_lock_bh (kernel/locking/spinlock.c:335) 
[ 7.765587][ T1] ? __neigh_ifdown+0x29/0x108 
[ 7.765993][ T1] ? neigh_ifdown (net/core/neighbour.c:488) 
[ 7.766325][ T1] ? arp_ifdown (net/ipv4/arp.c:1363) 
[ 7.766647][ T1] ? fib_inetaddr_event (net/ipv4/fib_frontend.c:1430 net/ipv4/fib_frontend.c:1454) 
[ 7.767026][ T1] ? notifier_call_chain (kernel/notifier.c:95) 
[ 7.767414][ T1] ? blocking_notifier_call_chain (kernel/notifier.c:388 kernel/notifier.c:376) 
[ 7.767858][ T1] ? __inet_del_ifa (net/ipv4/devinet.c:447) 
[ 7.768226][ T1] ? devinet_ioctl (net/ipv4/devinet.c:1253) 
[ 7.768589][ T1] ? ic_setup_if (net/ipv4/ipconfig.c:382) 
[ 7.768934][ T1] ? ip_auto_config (net/ipv4/ipconfig.c:1652) 
[ 7.769343][ T1] ? root_nfs_parse_addr (net/ipv4/ipconfig.c:1477) 
[ 7.769729][ T1] ? do_one_initcall (init/main.c:1269) 
[ 7.770099][ T1] ? do_initcalls (init/main.c:1330 init/main.c:1347) 
[ 7.770446][ T1] ? rest_init (init/main.c:1461) 
[ 7.770779][ T1] ? kernel_init_freeable (init/main.c:1584) 
[ 7.771175][ T1] ? kernel_init (init/main.c:1471) 
[ 7.771514][ T1] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 7.771860][ T1] ? rest_init (init/main.c:1461) 
[ 7.772192][ T1] ? ret_from_fork_asm (arch/x86/entry/entry_32.S:737) 
[ 7.772563][ T1] ? entry_INT80_32 (arch/x86/entry/entry_32.S:941) 



The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20241009/202410091223.b011d2e6-lkp@intel.com



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