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BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x471/0x4b0
Read of size 2 at addr ffff888038dc102a by task syz.2.3749/20730

CPU: 0 UID: 0 PID: 20730 Comm: syz.2.3749 Not tainted 6.16.0-syzkaller-12063-g37816488247d #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
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:_raw_read_unlock_irqrestore+0xa8/0x110
Code: 74 05 e8 0b 01 4c f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 53 a8 14 f6 65 8b 05 cc 9b 24 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc900079a7d00 EFLAGS: 00000206
RAX: d522c0bc3a10c300 RBX: 0000000000000a06 RCX: d522c0bc3a10c300
RDX: 0000000000000000 RSI: ffffffff8d9b4943 RDI: 0000000000000001
RBP: ffffc900079a7d98 R08: ffffffff8fa34737 R09: 1ffffffff1f468e6
R10: dffffc0000000000 R11: fffffbfff1f468e7 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8f597fc0 R15: 1ffff92000f34fa0
 netlink_create+0xfa/0x590
 __sock_create+0x4b3/0x9f0
 __sys_socket+0xd7/0x1b0
 __x64_sys_socket+0x7a/0x90
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2519990b07
Code: f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f251a754fa8 EFLAGS: 00000286 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f2519bb6180 RCX: 00007f2519990b07
RDX: 0000000000000010 RSI: 0000000000000003 RDI: 0000000000000010
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000240 R11: 0000000000000286 R12: 0000000000000000
R13: 00007f2519bb6218 R14: 00007f2519bb6180 R15: 00007ffe669745e8
 </TASK>

Allocated by task 19684:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x230/0x3d0
 inetdev_init+0x7d/0x500
 inetdev_event+0x301/0x15b0
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 __ip_tunnel_create+0x3e7/0x560
 ip_tunnel_init_net+0x2ba/0x800
 ops_init+0x35c/0x5c0
 setup_net+0x10c/0x320
 copy_net_ns+0x31b/0x4d0
 create_new_namespaces+0x3f3/0x720
 unshare_nsproxy_namespaces+0x11c/0x170
 ksys_unshare+0x4c8/0x8c0
 __x64_sys_unshare+0x38/0x50
 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
 inetdev_event+0x81c/0x15b0
 notifier_call_chain+0x1b6/0x3e0
 unregister_netdevice_many_notify+0x14d7/0x1ff0
 ops_undo_list+0x3dc/0x990
 setup_net+0x2d3/0x320
 copy_net_ns+0x31b/0x4d0
 create_new_namespaces+0x3f3/0x720
 unshare_nsproxy_namespaces+0x11c/0x170
 ksys_unshare+0x4c8/0x8c0
 __x64_sys_unshare+0x38/0x50
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888038dc1000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 42 bytes inside of
 freed 512-byte region [ffff888038dc1000, ffff888038dc1200)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888038dc2800 pfn:0x38dc0
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801a441c80 ffffea00008ead10 ffffea0000e2f510
raw: ffff888038dc2800 0000000000100006 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801a441c80 ffffea00008ead10 ffffea0000e2f510
head: ffff888038dc2800 0000000000100006 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000e37001 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 5838, tgid 5838 (syz-executor), ts 57882252889, free_ts 0
 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_noprof+0x305/0x4f0
 fib6_info_alloc+0x30/0xf0
 ip6_route_info_create+0x142/0x860
 ip6_route_add+0x49/0x1b0
 add_v4_addrs+0x8b3/0xbd0
 addrconf_init_auto_addrs+0x6da/0xa30
 addrconf_notify+0xacc/0x1010
 notifier_call_chain+0x1b6/0x3e0
 __dev_notify_flags+0x18d/0x2e0
 netif_change_flags+0xe8/0x1a0
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888038dc0f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888038dc0f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888038dc1000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888038dc1080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888038dc1100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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