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BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x471/0x4b0
Read of size 2 at addr ffff88802067742a by task syz.1.7945/1547

CPU: 1 UID: 0 PID: 1547 Comm: syz.1.7945 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
 __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:pfn_valid+0x30/0x490
Code: 55 41 54 53 49 89 fe e8 5e 4e 91 ff e9 f3 03 00 00 e8 54 4e 91 ff 49 bc 00 00 00 00 00 fc ff df e9 24 04 00 00 e8 40 4e 91 ff <48> c7 c0 00 b0 b1 99 48 c1 e8 03 42 80 3c 20 00 74 0c 48 c7 c7 00
RSP: 0018:ffffc90020b8f318 EFLAGS: 00000293
RAX: ffffffff822e6133 RBX: 8000000032003007 RCX: ffff888106535640
RDX: 0000000000000000 RSI: 0000000000032003 RDI: 0000000400000000
RBP: ffffc90020b8f650 R08: ffffea0000c800c7 R09: 1ffffd4000190018
R10: dffffc0000000000 R11: fffff94000190019 R12: dffffc0000000000
R13: 1ffffd400019001b R14: 0000000000032003 R15: 0000000000000000
 page_table_check_clear+0x21/0x700
 unmap_page_range+0x3445/0x4370
 unmap_vmas+0x399/0x580
 exit_mmap+0x248/0xb50
 __mmput+0x118/0x420
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4c5d78ebe9
Code: Unable to access opcode bytes at 0x7f4c5d78ebbf.
RSP: 002b:00007f4c5e5b30e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f4c5d9b6098 RCX: 00007f4c5d78ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4c5d9b6098
RBP: 00007f4c5d9b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4c5d9b6128 R14: 00007ffd16d32410 R15: 00007ffd16d324f8
 </TASK>

Allocated by task 1427:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x230/0x3d0
 __genradix_ptr_alloc+0x352/0x4a0
 __genradix_prealloc+0x44/0x90
 sctp_stream_init+0x14b/0x440
 sctp_association_new+0x10dd/0x25f0
 sctp_connect_new_asoc+0x2c5/0x690
 sctp_sendmsg+0x155c/0x2810
 __sock_sendmsg+0x19c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 1427:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kfree+0x18e/0x440
 genradix_free_recurse+0x5d/0xa0
 genradix_free_recurse+0x5d/0xa0
 sctp_stream_free+0xd5/0x110
 sctp_association_free+0x26d/0x7f0
 sctp_do_sm+0x3eba/0x5a20
 sctp_primitive_SHUTDOWN+0x98/0xc0
 sctp_close+0x409/0x900
 inet_release+0x144/0x190
 sock_close+0xc3/0x240
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 get_signal+0x11ed/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888020677400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 42 bytes inside of
 freed 512-byte region [ffff888020677400, ffff888020677600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20674
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a441c80 0000000000000000 dead000000000001
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000819d01 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 7755, tgid 7754 (syz.2.490), ts 84159510934, free_ts 76978134976
 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
 device_add+0xbe/0xb50
 netdev_register_kobject+0x178/0x310
 register_netdevice+0x126c/0x1ae0
 register_netdev+0x40/0x60
 loopback_net_init+0x75/0x150
 ops_init+0x35c/0x5c0
 setup_net+0x10c/0x320
 copy_net_ns+0x31b/0x4d0
 create_new_namespaces+0x3f3/0x720
page last free pid 5284 tgid 5284 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
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 __alloc_skb+0x112/0x2d0
 alloc_skb_with_frags+0xca/0x890
 sock_alloc_send_pskb+0x857/0x990
 unix_dgram_sendmsg+0x461/0x1850
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0

Memory state around the buggy address:
 ffff888020677300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888020677380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888020677400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888020677480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888020677500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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