[syzbot] [net?] WARNING in rt6_multipath_rebalance (2)
From: syzbot <hidden>
Date: 2025-05-01 11:16:38
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Hello, syzbot found the following issue on: HEAD commit: cc17b4b9c332 Merge branch 'io_uring-zcrx-fix-selftests-and.. git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=125b8374580000 kernel config: https://syzkaller.appspot.com/x/.config?x=7e367ce4a19f69ba dashboard link: https://syzkaller.appspot.com/bug?extid=d842f24c4e2bae159341 compiler: Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/0e09cf367bdd/disk-cc17b4b9.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/4ab63344d74c/vmlinux-cc17b4b9.xz kernel image: https://storage.googleapis.com/syzbot-assets/14915e0e32b3/bzImage-cc17b4b9.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d842f24c4e2bae159341@syzkaller.appspotmail.com batman_adv: batadv0: Removing interface: batadv_slave_1 veth1_macvtap: left promiscuous mode veth0_macvtap: left promiscuous mode veth1_vlan: left promiscuous mode veth0_vlan: left promiscuous mode ------------[ cut here ]------------ WARNING: CPU: 0 PID: 36 at net/ipv6/route.c:4822 rt6_multipath_rebalance+0x455/0x8b0 net/ipv6/route.c:4822 Modules linked in: CPU: 0 UID: 0 PID: 36 Comm: kworker/u8:2 Not tainted 6.15.0-rc3-syzkaller-00584-gcc17b4b9c332 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Workqueue: netns cleanup_net RIP: 0010:rt6_multipath_rebalance+0x455/0x8b0 net/ipv6/route.c:4822 Code: ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 85 fe ff ff 4c 89 e7 e8 2d a0 13 f8 e9 78 fe ff ff e8 e3 aa b1 f7 eb 05 e8 dc aa b1 f7 90 <0f> 0b 90 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc RSP: 0018:ffffc90000ad6ee0 EFLAGS: 00010293 RAX: ffffffff8a0e129d RBX: ffff88802f515000 RCX: ffff8881412d9e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200015add4 R12: ffff88802f5150de R13: ffff88802f515090 R14: 0000000000000000 R15: 1ffff11005ea2a12 FS: 0000000000000000(0000) GS:ffff8881260c4000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f94077eeb68 CR3: 000000000dd36000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> fib6_ifdown+0x401/0x4c0 net/ipv6/route.c:4942 fib6_clean_node+0x24a/0x590 net/ipv6/ip6_fib.c:2249 fib6_walk_continue+0x678/0x910 net/ipv6/ip6_fib.c:2174 fib6_walk+0x149/0x290 net/ipv6/ip6_fib.c:2222 fib6_clean_tree net/ipv6/ip6_fib.c:2302 [inline] __fib6_clean_all+0x234/0x380 net/ipv6/ip6_fib.c:2318 rt6_sync_down_dev net/ipv6/route.c:4970 [inline] rt6_disable_ip+0x120/0x720 net/ipv6/route.c:4975 addrconf_ifdown+0x15d/0x1880 net/ipv6/addrconf.c:3854 addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2266 [inline] call_netdevice_notifiers net/core/dev.c:2280 [inline] dev_close_many+0x29c/0x410 net/core/dev.c:1783 unregister_netdevice_many_notify+0x834/0x2320 net/core/dev.c:12006 unregister_netdevice_many net/core/dev.c:12099 [inline] default_device_exit_batch+0x819/0x890 net/core/dev.c:12601 ops_exit_list net/core/net_namespace.c:206 [inline] ops_undo_list+0x522/0x990 net/core/net_namespace.c:253 cleanup_net+0x4c5/0x8a0 net/core/net_namespace.c:686 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup