==================================================================
BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x471/0x4b0
Read of size 2 at addr ffff88810fdb5c2a by task sshd/5831

CPU: 1 UID: 0 PID: 5831 Comm: sshd 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:
 <IRQ>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 rose_timer_expiry+0x471/0x4b0
 call_timer_fn+0x17e/0x5f0
 __run_timer_base+0x61a/0x860
 run_timer_softirq+0xb7/0x180
 handle_softirqs+0x286/0x870
 do_softirq+0xec/0x180
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0
 __dev_queue_xmit+0x1d79/0x3b50
 ip_finish_output2+0xd03/0x1160
 ip_output+0x2a1/0x3c0
 __ip_queue_xmit+0x118d/0x1c30
 __tcp_transmit_skb+0x2215/0x3680
 tcp_write_xmit+0x1862/0x67f0
 tcp_sendmsg_locked+0x2b9f/0x5620
 tcp_sendmsg+0x2f/0x50
 __sock_sendmsg+0x19c/0x270
 sock_write_iter+0x258/0x330
 vfs_write+0x5c9/0xb30
 ksys_write+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4de0d16bf2
Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffcbc3d4de8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000008024 RCX: 00007f4de0d16bf2
RDX: 0000000000008024 RSI: 000055c3e1477cc0 RDI: 0000000000000004
RBP: 000055c3e140e110 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000055c3bdccaaa4
R13: 0000000000000174 R14: 000055c3bdccb3e8 R15: 00007ffcbc3d4e58
 </TASK>

Allocated by task 22705:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x27a/0x4f0
 fib6_info_alloc+0x30/0xf0
 ip6_route_info_create+0x142/0x860
 ip6_route_add+0x49/0x1b0
 addrconf_add_dev+0x24f/0x340
 addrconf_init_auto_addrs+0x57c/0xa30
 addrconf_notify+0xacc/0x1010
 notifier_call_chain+0x1b6/0x3e0
 __dev_notify_flags+0x18d/0x2e0
 netif_change_flags+0xe8/0x1a0
 dev_change_flags+0x130/0x260
 devinet_ioctl+0xbb4/0x1b50
 inet_ioctl+0x3c0/0x4c0
 sock_do_ioctl+0xdc/0x300
 sock_ioctl+0x576/0x790
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 15:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kfree+0x18e/0x440
 rcu_core+0xcab/0x1770
 handle_softirqs+0x286/0x870
 run_ksoftirqd+0x9b/0x100
 smpboot_thread_fn+0x542/0xa60
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 call_rcu+0x157/0x9c0
 fib6_del+0x111f/0x1550
 fib6_clean_node+0x29f/0x590
 fib6_walk_continue+0x67b/0x910
 fib6_walk+0x149/0x290
 __fib6_clean_all+0x234/0x380
 rt6_disable_ip+0x120/0x720
 addrconf_ifdown+0x15d/0x1880
 addrconf_notify+0x1bc/0x1010
 notifier_call_chain+0x1b6/0x3e0
 netif_close_many+0x29c/0x410
 unregister_netdevice_many_notify+0x7b9/0x1ff0
 unregister_netdevice_queue+0x33c/0x380
 __tun_detach+0xda4/0x1560
 tun_chr_close+0x10a/0x1c0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88810fdb5c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 42 bytes inside of
 freed 512-byte region [ffff88810fdb5c00, ffff88810fdb5e00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10fdb4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 057ff00000000002 ffffea00043f6d01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12175, tgid 12174 (syz.1.1696), ts 155921200213, free_ts 154088330786
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x370
 ___slab_alloc+0xbeb/0x1410
 __kmalloc_cache_noprof+0x296/0x3d0
 __genradix_ptr_alloc+0x352/0x4a0
 __genradix_prealloc+0x44/0x90
 sctp_stream_init+0x14b/0x440
 sctp_connect_new_asoc+0x3a6/0x690
 sctp_sendmsg+0x155c/0x2810
 __sock_sendmsg+0x19c/0x270
 ____sys_sendmsg+0x52d/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __sys_sendmmsg+0x227/0x430
page last free pid 5711 tgid 5711 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __put_partials+0x156/0x1a0
 put_cpu_partial+0x17c/0x250
 __slab_free+0x2d5/0x3c0
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 __kmalloc_noprof+0x224/0x4f0
 unregister_netdevice_many_notify+0x88e/0x1ff0
 default_device_exit_batch+0x819/0x890
 ops_undo_list+0x525/0x990
 cleanup_net+0x4c5/0x800
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770

Memory state around the buggy address:
 ffff88810fdb5b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810fdb5b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810fdb5c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff88810fdb5c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810fdb5d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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