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BUG: KASAN: slab-out-of-bounds in dtSplitPage+0x12c6/0x3b20
Read of size 1 at addr ffff8881a8c3c8cd by task syz.1.66/6122

CPU: 1 UID: 0 PID: 6122 Comm: syz.1.66 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+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 dtSplitPage+0x12c6/0x3b20
 dtInsert+0x109b/0x5f40
 jfs_mkdir+0x6ec/0xa70
 vfs_mkdir+0x306/0x510
 do_mkdirat+0x247/0x590
 __x64_sys_mkdirat+0x87/0xa0
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f69fc18eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f69fd06c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f69fc3e5fa0 RCX: 00007f69fc18eec9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: ffffffffffffff9c
RBP: 00007f69fc211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f69fc3e6038 R14: 00007f69fc3e5fa0 R15: 00007ffdcbb77918
 </TASK>

Allocated by task 6122:
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_lru_noprof+0x35d/0x6d0
 jfs_alloc_inode+0x28/0x70
 alloc_inode+0x6a/0x1b0
 iget_locked+0x106/0x580
 jfs_iget+0x24/0x470
 jfs_lookup+0x1c5/0x380
 __lookup_slow+0x297/0x3d0
 lookup_slow+0x53/0x70
 walk_component+0x2d2/0x400
 path_lookupat+0x163/0x430
 filename_lookup+0x212/0x570
 user_path_at+0x3a/0x60
 __se_sys_chdir+0x91/0x280
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8881a8c3c018
 which belongs to the cache jfs_ip of size 2216
The buggy address is located 13 bytes to the right of
 allocated 2216-byte region [ffff8881a8c3c018, ffff8881a8c3c8c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1a8c38
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8881692e7f01
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88816963f8c0 dead000000000122 0000000000000000
raw: 0000000000000000 00000000000d000d 00000000f5000000 ffff8881692e7f01
head: 057ff00000000040 ffff88816963f8c0 dead000000000122 0000000000000000
head: 0000000000000000 00000000000d000d 00000000f5000000 ffff8881692e7f01
head: 057ff00000000003 ffffea0006a30e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0xd2050(__GFP_RECLAIMABLE|__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5929, tgid 5926 (syz.0.23), ts 66887161450, free_ts 23170619937
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x2365/0x2440
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x96/0x3a0
 ___slab_alloc+0xe94/0x1920
 __slab_alloc+0x65/0x100
 kmem_cache_alloc_lru_noprof+0x3ef/0x6d0
 jfs_alloc_inode+0x28/0x70
 alloc_inode+0x6a/0x1b0
 new_inode+0x22/0x170
 jfs_fill_super+0x569/0xd80
 get_tree_bdev_flags+0x40e/0x4d0
 vfs_get_tree+0x92/0x2b0
 do_new_mount+0x302/0xa10
 __se_sys_mount+0x313/0x410
page last free pid 1 tgid 1 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 free_contig_range+0x1bd/0x4a0
 destroy_args+0x69/0x660
 debug_vm_pgtable+0x39f/0x3b0
 do_one_initcall+0x236/0x820
 do_initcall_level+0x104/0x190
 do_initcalls+0x59/0xa0
 kernel_init_freeable+0x334/0x4b0
 kernel_init+0x1d/0x1d0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30

Memory state around the buggy address:
 ffff8881a8c3c780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881a8c3c800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881a8c3c880: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                              ^
 ffff8881a8c3c900: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff8881a8c3c980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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