==================================================================
BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x471/0x4b0
Read of size 2 at addr ffff88803a07ec2a by task swapper/0/0

CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.16.0-syzkaller-06620-gae633388cae3 #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
 tmigr_handle_remote+0xa32/0x13d0
 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:pv_native_safe_halt+0x13/0x20
Code: 53 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 13 6f 18 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 00000282
RAX: 0ee9db944ee7ae00 RBX: ffffffff81969b18 RCX: 0ee9db944ee7ae00
RDX: 0000000000000001 RSI: ffffffff8d9792a2 RDI: ffffffff8be30a00
RBP: ffffffff8de07eb8 R08: ffff88804b032f5b R09: 1ffff110096065eb
R10: dffffc0000000000 R11: ffffed10096065ec R12: ffffffff8fa07bf0
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a18
 default_idle+0x13/0x20
 default_idle_call+0x74/0xb0
 do_idle+0x1e8/0x510
 cpu_startup_entry+0x44/0x60
 rest_init+0x2de/0x300
 start_kernel+0x3a9/0x410
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x143/0x1c0
 common_startup_64+0x13e/0x147
 </TASK>

Allocated by task 21004:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_node_noprof+0x276/0x4e0
 allocate_slab+0x17c/0x3b0
 ___slab_alloc+0xbfc/0x1480
 kmem_cache_alloc_noprof+0x283/0x3c0
 __send_signal_locked+0x22a/0xeb0
 group_send_sig_info+0x1fd/0x260
 do_bpf_send_signal+0xa9/0x1c0
 irq_work_single+0xe1/0x240
 irq_work_run+0x155/0x2f0
 __sysvec_irq_work+0xa8/0x3d0
 sysvec_irq_work+0x9e/0xc0
 asm_sysvec_irq_work+0x1a/0x20

Freed by task 21156:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x62/0x70
 kfree+0x18e/0x440
 __free_slab+0xb9/0x1c0
 __put_partials+0x161/0x1c0
 put_cpu_partial+0x17c/0x250
 __slab_free+0x2f7/0x400
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 __kmalloc_cache_noprof+0x1be/0x3d0
 ref_tracker_alloc+0x133/0x460
 register_netdevice+0x14a3/0x1ae0
 __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

The buggy address belongs to the object at ffff88803a07ec00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 42 bytes inside of
 freed 512-byte region [ffff88803a07ec00, ffff88803a07ee00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803a07e800 pfn:0x3a07c
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 ffffea0000901210 ffffea0000e7b610
raw: ffff88803a07e800 000000000010000e 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801a441c80 ffffea0000901210 ffffea0000e7b610
head: ffff88803a07e800 000000000010000e 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000e81f01 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 5824, tgid 5824 (syz-executor), ts 67673929624, 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/0x3b0
 ___slab_alloc+0xbfc/0x1480
 __kmalloc_noprof+0x305/0x4f0
 fib6_info_alloc+0x30/0xf0
 ip6_route_info_create+0x142/0x860
 addrconf_f6i_alloc+0x1d2/0x450
 ipv6_add_addr+0x56e/0x1090
 add_addr+0x8b/0x2d0
 add_v4_addrs+0x70c/0xbd0
 addrconf_init_auto_addrs+0x6da/0xa30
 addrconf_notify+0xacc/0x1010
 notifier_call_chain+0x1b6/0x3e0
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88803a07eb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803a07eb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88803a07ec00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff88803a07ec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803a07ed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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