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BUG: KASAN: slab-use-after-free in ocfs2_fault+0xdb/0x440
Read of size 8 at addr ffff888172af8658 by task syz.5.172/7226

CPU: 0 UID: 0 PID: 7226 Comm: syz.5.172 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:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_report+0xba/0x230
 kasan_report+0x117/0x150
 ocfs2_fault+0xdb/0x440
 __do_fault+0x138/0x390
 do_pte_missing+0x228f/0x3490
 handle_mm_fault+0x1bec/0x3310
 __get_user_pages+0x165b/0x29d0
 populate_vma_page_range+0x2be/0x3c0
 __mm_populate+0x25f/0x390
 vm_mmap_pgoff+0x3aa/0x4f0
 ksys_mmap_pgoff+0x51e/0x760
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f700839c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f70092e5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f7008615fa0 RCX: 00007f700839c799
RDX: 00000000027ffff7 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007f7008432c99 R08: 0000000000000007 R09: 0000000000002000
R10: 0000000004012011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7008616038 R14: 00007f7008615fa0 R15: 00007fff8c213f98
 </TASK>

Allocated by task 7226:
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x2bc/0x650
 vm_area_alloc+0x24/0x140
 mmap_region+0x10eb/0x2240
 do_mmap+0xc39/0x10c0
 vm_mmap_pgoff+0x2c9/0x4f0
 ksys_mmap_pgoff+0x51e/0x760
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 4826:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 slab_free_after_rcu_debug+0x126/0x220
 rcu_core+0x7cd/0x1070
 handle_softirqs+0x22a/0x870
 do_softirq+0x76/0xd0
 __local_bh_enable_ip+0xf8/0x130
 __alloc_skb+0x1aa/0x7d0
 nsim_dev_trap_report_work+0x29a/0xb80
 process_scheduled_works+0xb02/0x1830
 worker_thread+0xa50/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 kmem_cache_free+0x426/0x630
 vms_complete_munmap_vmas+0x929/0xc60
 __mmap_complete+0x7b/0x5e0
 mmap_region+0x1d91/0x2240
 do_mmap+0xc39/0x10c0
 vm_mmap_pgoff+0x2c9/0x4f0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888172af8600
 which belongs to the cache vm_area_struct of size 256
The buggy address is located 88 bytes inside of
 freed 256-byte region [ffff888172af8600, ffff888172af8700)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x172af8
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888172af8121
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff8881012d2b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000018000150015 00000000f5000000 ffff888172af8121
head: 057ff00000000040 ffff8881012d2b40 dead000000000100 dead000000000122
head: 0000000000000000 0000018000150015 00000000f5000000 ffff888172af8121
head: 057ff00000000001 ffffea0005cabe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 7228, tgid 7228 (udevadm), ts 118500369108, free_ts 109701114777
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x24dc/0x2580
 __alloc_frozen_pages_noprof+0x18d/0x380
 allocate_slab+0x77/0x660
 refill_objects+0x331/0x3c0
 __pcs_replace_empty_main+0x2f9/0x5e0
 kmem_cache_alloc_noprof+0x37d/0x650
 vm_area_dup+0x2b/0x680
 __split_vma+0x1dc/0xa40
 vms_gather_munmap_vmas+0x32d/0x1370
 mmap_region+0x85b/0x2240
 do_mmap+0xc39/0x10c0
 vm_mmap_pgoff+0x2c9/0x4f0
 ksys_mmap_pgoff+0x51e/0x760
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 23 tgid 23 stack trace:
 __free_frozen_pages+0xc2b/0xdb0
 rcu_core+0x7cd/0x1070
 handle_softirqs+0x22a/0x870
 run_ksoftirqd+0x36/0x60
 smpboot_thread_fn+0x541/0xa50
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

Memory state around the buggy address:
 ffff888172af8500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888172af8580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888172af8600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff888172af8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888172af8700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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