syzbot

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BUG: KASAN: use-after-free in dev_net include/linux/netdevice.h:2220 [inline]
BUG: KASAN: use-after-free in ipv6_get_ifaddr+0x4b6/0x560 net/ipv6/addrconf.c:2001
Read of size 8 at addr ffff88805b93e588 by task kworker/1:24/2745

CPU: 1 PID: 2745 Comm: kworker/1:24 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rcu_gp process_srcu
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:641
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 dev_net include/linux/netdevice.h:2220 [inline]
 ipv6_get_ifaddr+0x4b6/0x560 net/ipv6/addrconf.c:2001
 ndisc_send_rs+0x188/0x720 net/ipv6/ndisc.c:668
 addrconf_rs_timer+0x30f/0x6e0 net/ipv6/addrconf.c:3879
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1146
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline]
RIP: 0010:queue_delayed_work_on+0x12a/0x210 kernel/workqueue.c:1673
Code: 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 d8 00 00 00 48 83 3d 1e 2f 66 08 00 0f 84 9a 00 00 00 e8 8b 0f 28 00 48 89 df 57 9d <0f> 1f 44 00 00 e8 7c 0f 28 00 44 89 f8 48 83 c4 10 5b 41 5c 41 5d
RSP: 0018:ffffc90008637bd0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffff8880a0162400 RBX: 0000000000000293 RCX: 0000000000000006
RDX: 0000000000000000 RSI: ffffffff814d81a5 RDI: 0000000000000293
RBP: ffffc90008637c08 R08: 1ffffffff16a3371 R09: fffffbfff16a3372
R10: fffffbfff16a3371 R11: ffffffff8b519b8f R12: 0000000000000200
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
 queue_delayed_work include/linux/workqueue.h:509 [inline]
 srcu_reschedule kernel/rcu/srcutree.c:1226 [inline]
 srcu_reschedule+0xd7/0x130 kernel/rcu/srcutree.c:1209
 process_srcu+0x125/0xe10 kernel/rcu/srcutree.c:1239
 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 10138:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529
 __do_kmalloc_node mm/slab.c:3616 [inline]
 __kmalloc_node+0x4e/0x70 mm/slab.c:3623
 kmalloc_node include/linux/slab.h:578 [inline]
 kvmalloc_node+0x68/0x100 mm/util.c:574
 kvmalloc include/linux/mm.h:645 [inline]
 kvzalloc include/linux/mm.h:653 [inline]
 alloc_netdev_mqs+0x98/0xe40 net/core/dev.c:9797
 vti6_init_net+0x244/0x810 net/ipv6/ip6_vti.c:1119
 ops_init+0xb3/0x420 net/core/net_namespace.c:137
 setup_net+0x2d5/0x8b0 net/core/net_namespace.c:327
 copy_net_ns+0x29e/0x5a0 net/core/net_namespace.c:468
 create_new_namespaces+0x403/0xb50 kernel/nsproxy.c:108
 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:229
 ksys_unshare+0x444/0x980 kernel/fork.c:2955
 __do_sys_unshare kernel/fork.c:3023 [inline]
 __se_sys_unshare kernel/fork.c:3021 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3021
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 13476:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 __netdev_name_node_alt_destroy+0x1ff/0x2a0 net/core/dev.c:322
 netdev_name_node_alt_destroy+0x57/0x80 net/core/dev.c:334
 rtnl_alt_ifname net/core/rtnetlink.c:3518 [inline]
 rtnl_linkprop.isra.0+0x575/0x6f0 net/core/rtnetlink.c:3567
 rtnl_dellinkprop+0x46/0x60 net/core/rtnetlink.c:3588
 rtnetlink_rcv_msg+0x45e/0xaf0 net/core/rtnetlink.c:5438
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5456
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 ____sys_sendmsg+0x753/0x880 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430
 __do_sys_sendmsg net/socket.c:2439 [inline]
 __se_sys_sendmsg net/socket.c:2437 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88805b93e000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1416 bytes inside of
 4096-byte region [ffff88805b93e000, ffff88805b93f000)
The buggy address belongs to the page:
page:ffffea00016e4f80 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00016e4608 ffffea00016e5908 ffff8880aa402000
raw: 0000000000000000 ffff88805b93e000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805b93e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805b93e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805b93e580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88805b93e600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805b93e680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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