syzbot ci has tested the following series
[v4] ipvlan: support mac-nat mode https://lore.kernel.org/all/20251118100046.2944392-1-skorodumov.dmitry@huawe... * [PATCH net-next 01/13] ipvlan: Support MACNAT mode * [PATCH net-next 02/13] ipvlan: macnat: Handle rx mcast-ip and unicast eth * [PATCH net-next 03/13] ipvlan: Forget all IP when device goes down * [PATCH net-next 04/13] ipvlan: Support IPv6 in macnat mode. * [PATCH net-next 05/13] ipvlan: Fix compilation warning about __be32 -> u32 * [PATCH net-next 06/13] ipvlan: Make the addrs_lock be per port * [PATCH net-next 07/13] ipvlan: Take addr_lock in ipvlan_open() * [PATCH net-next 08/13] ipvlan: Don't allow children to use IPs of main * [PATCH net-next 09/13] ipvlan: const-specifier for functions that use iaddr * [PATCH net-next 10/13] ipvlan: Common code from v6/v4 validator_event * [PATCH net-next 11/13] ipvlan: common code to handle ipv6/ipv4 address events * [PATCH net-next 12/13] ipvlan: Ignore PACKET_LOOPBACK in handle_mode_l2() * [PATCH net-next 13/13] selftests: drv-net: selftest for ipvlan-macnat mode
and found the following issue: WARNING: suspicious RCU usage in ipvlan_addr_event
Full report is available here: https://ci.syzbot.org/series/e483b93a-1063-4c8a-b0e2-89530e79768b
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WARNING: suspicious RCU usage in ipvlan_addr_event
tree: net-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/netdev/net-next.git base: c99ebb6132595b4b288a413981197eb076547c5a arch: amd64 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 config: https://ci.syzbot.org/builds/ac5af6f3-6b14-4e35-9d81-ee1522de3952/config
8021q: adding VLAN 0 to HW filter on device batadv0 ============================= WARNING: suspicious RCU usage syzkaller #0 Not tainted ----------------------------- drivers/net/ipvlan/ipvlan.h:128 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1 2 locks held by syz-executor/5984: #0: ffffffff8f2cc248 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 #1: ffffffff8f39d9b0 ((inetaddr_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90
stack backtrace: CPU: 1 UID: 0 PID: 5984 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lockdep_rcu_suspicious+0x140/0x1d0 ipvlan_addr_event+0x60b/0x950 notifier_call_chain+0x1b6/0x3e0 blocking_notifier_call_chain+0x6a/0x90 __inet_insert_ifa+0xa13/0xbf0 inet_rtm_newaddr+0xf3a/0x18b0 rtnetlink_rcv_msg+0x7cf/0xb70 netlink_rcv_skb+0x208/0x470 netlink_unicast+0x82f/0x9e0 netlink_sendmsg+0x805/0xb30 __sock_sendmsg+0x21c/0x270 __sys_sendto+0x3bd/0x520 __x64_sys_sendto+0xde/0x100 do_syscall_64+0xfa/0xfa0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f711f191503 Code: 64 89 02 48 c7 c0 ff ff ff ff eb b7 66 2e 0f 1f 84 00 00 00 00 00 90 80 3d 61 70 22 00 00 41 89 ca 74 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 55 48 83 ec 30 44 89 4c 24 RSP: 002b:00007ffc44b05f28 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f711ff14620 RCX: 00007f711f191503 RDX: 0000000000000028 RSI: 00007f711ff14670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffc44b05f44 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f711ff14670 R15: 0000000000000000 </TASK> syz-executor (5984) used greatest stack depth: 19864 bytes left
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If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com
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