hpfs: You really don't want any checks? You are crazy...
hpfs: hpfs_map_sector(): read error
hpfs: code page support is disabled
==================================================================
BUG: KASAN: slab-use-after-free in strcmp+0x6b/0xc0
Read of size 1 at addr ffff88810e0508a6 by task syz.1.235/7648

CPU: 1 UID: 0 PID: 7648 Comm: syz.1.235 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
 strcmp+0x6b/0xc0
 hpfs_get_ea+0x134/0xee0
 hpfs_read_inode+0x1a6/0x1050
 hpfs_fill_super+0x123d/0x1fa0
 get_tree_bdev_flags+0x431/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x341/0xd30
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2bec39da0a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f2bed241e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2bed241ee0 RCX: 00007f2bec39da0a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007f2bed241ea0
RBP: 000020000000a000 R08: 00007f2bed241ee0 R09: 0000000001200041
R10: 0000000001200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f2bed241ea0 R14: 0000000000009e15 R15: 0000200000000280
 </TASK>

Allocated by task 1093:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_node_track_caller_noprof+0x4db/0x7b0
 __alloc_skb+0x2c1/0x7d0
 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

Freed by task 1093:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c1/0x630
 skb_release_data+0x6f0/0x940
 __kfree_skb+0x5d/0x210
 nsim_dev_trap_report_work+0x7cf/0xb80
 process_scheduled_works+0xb02/0x1830
 worker_thread+0xa50/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff88810e050000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2214 bytes inside of
 freed 4096-byte region [ffff88810e050000, ffff88810e051000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e050
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888100042140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888100042140 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 017ff00000000003 ffffea0004381401 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 Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 7452, tgid 7451 (syz.5.206), ts 116387258777, free_ts 71849538570
 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+0x2b9/0x620
 __kmalloc_cache_noprof+0x392/0x660
 alloc_super+0x5b/0xab0
 sget_fc+0x329/0xa40
 get_tree_bdev_flags+0x214/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x341/0xd30
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6026 tgid 6025 stack trace:
 __free_frozen_pages+0xc2b/0xdb0
 __slab_free+0x263/0x2b0
 qlist_free_all+0x97/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_noprof+0x2bc/0x650
 ptlock_alloc+0x20/0x70
 pte_alloc_one+0x7a/0x370
 __pte_alloc+0x25/0x430
 do_pte_missing+0x2e9a/0x3750
 handle_mm_fault+0x1bec/0x3310
 do_user_addr_fault+0xa73/0x1340
 exc_page_fault+0x6a/0xc0
 asm_exc_page_fault+0x26/0x30

Memory state around the buggy address:
 ffff88810e050780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810e050800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810e050880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88810e050900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810e050980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
