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: use-after-free in strcmp+0xa7/0xb0 lib/string.c:283
Read of size 1 at addr ffff8880686438a6 by task syz.2.857/9860

CPU: 0 UID: 0 PID: 9860 Comm: syz.2.857 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 strcmp+0xa7/0xb0 lib/string.c:283
 hpfs_get_ea+0x1f9/0xc90 fs/hpfs/ea.c:139
 hpfs_read_inode+0x69e/0x1270 fs/hpfs/inode.c:63
 hpfs_fill_super+0x13e9/0x2230 fs/hpfs/super.c:654
 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1692
 vfs_get_tree+0x8e/0x340 fs/super.c:1815
 do_new_mount fs/namespace.c:3808 [inline]
 path_mount+0x1513/0x2000 fs/namespace.c:4123
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount fs/namespace.c:4324 [inline]
 __x64_sys_mount+0x28d/0x310 fs/namespace.c:4324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f47fdd9034a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f47feb5fe68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f47feb5fef0 RCX: 00007f47fdd9034a
RDX: 000020000000a000 RSI: 0000200000000000 RDI: 00007f47feb5feb0
RBP: 000020000000a000 R08: 00007f47feb5fef0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f47feb5feb0 R14: 0000000000009e15 R15: 0000200000000040
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x44c pfn:0x68643
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 000000000000044c 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 9812, tgid 9809 (syz.8.847), ts 551787088209, free_ts 552797490410
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2435
 shmem_alloc_folio+0x135/0x160 mm/shmem.c:1908
 shmem_alloc_and_add_folio+0x499/0xc20 mm/shmem.c:1947
 shmem_get_folio_gfp+0x67f/0x1600 mm/shmem.c:2597
 shmem_fault+0x1fe/0xa30 mm/shmem.c:2798
 __do_fault+0x10d/0x490 mm/memory.c:5152
 do_read_fault mm/memory.c:5573 [inline]
 do_fault mm/memory.c:5707 [inline]
 do_pte_missing+0xf50/0x3ba0 mm/memory.c:4234
 handle_pte_fault mm/memory.c:6052 [inline]
 __handle_mm_fault+0x152a/0x2a50 mm/memory.c:6195
 handle_mm_fault+0x589/0xd10 mm/memory.c:6364
 faultin_page mm/gup.c:1144 [inline]
 __get_user_pages+0x551/0x34a0 mm/gup.c:1446
 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1880
 __mm_populate+0x1d8/0x380 mm/gup.c:1983
page last free pid 9819 tgid 9809 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 free_unref_folios+0xa61/0x16b0 mm/page_alloc.c:2952
 folios_put_refs+0x56f/0x740 mm/swap.c:997
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x58f/0x1150 mm/shmem.c:1157
 shmem_truncate_range mm/shmem.c:1269 [inline]
 shmem_evict_inode+0x3a1/0xbe0 mm/shmem.c:1397
 evict+0x3e6/0x920 fs/inode.c:810
 iput_final fs/inode.c:1897 [inline]
 iput fs/inode.c:1923 [inline]
 iput+0x521/0x880 fs/inode.c:1909
 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:466
 __dentry_kill+0x1d0/0x600 fs/dcache.c:669
 dput.part.0+0x4b1/0x9b0 fs/dcache.c:911
 dput+0x1f/0x30 fs/dcache.c:901
 __fput+0x51c/0xb70 fs/file_table.c:476
 task_work_run+0x150/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x86f/0x2bf0 kernel/exit.c:961
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337

Memory state around the buggy address:
 ffff888068643780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888068643800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888068643880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff888068643900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888068643980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
==================================================================
BUG: KASAN: use-after-free in next_ea fs/hpfs/hpfs_fn.h:152 [inline]
BUG: KASAN: use-after-free in hpfs_get_ea+0xb51/0xc90 fs/hpfs/ea.c:138
Read of size 1 at addr ffff8880686438a3 by task syz.2.857/9860

CPU: 1 UID: 0 PID: 9860 Comm: syz.2.857 Tainted: G    B               syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 next_ea fs/hpfs/hpfs_fn.h:152 [inline]
 hpfs_get_ea+0xb51/0xc90 fs/hpfs/ea.c:138
 hpfs_read_inode+0x69e/0x1270 fs/hpfs/inode.c:63
 hpfs_fill_super+0x13e9/0x2230 fs/hpfs/super.c:654
 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1692
 vfs_get_tree+0x8e/0x340 fs/super.c:1815
 do_new_mount fs/namespace.c:3808 [inline]
 path_mount+0x1513/0x2000 fs/namespace.c:4123
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount fs/namespace.c:4324 [inline]
 __x64_sys_mount+0x28d/0x310 fs/namespace.c:4324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f47fdd9034a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f47feb5fe68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f47feb5fef0 RCX: 00007f47fdd9034a
RDX: 000020000000a000 RSI: 0000200000000000 RDI: 00007f47feb5feb0
RBP: 000020000000a000 R08: 00007f47feb5fef0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f47feb5feb0 R14: 0000000000009e15 R15: 0000200000000040
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x44c pfn:0x68643
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 000000000000044c 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 9812, tgid 9809 (syz.8.847), ts 551787088209, free_ts 552797490410
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2435
 shmem_alloc_folio+0x135/0x160 mm/shmem.c:1908
 shmem_alloc_and_add_folio+0x499/0xc20 mm/shmem.c:1947
 shmem_get_folio_gfp+0x67f/0x1600 mm/shmem.c:2597
 shmem_fault+0x1fe/0xa30 mm/shmem.c:2798
 __do_fault+0x10d/0x490 mm/memory.c:5152
 do_read_fault mm/memory.c:5573 [inline]
 do_fault mm/memory.c:5707 [inline]
 do_pte_missing+0xf50/0x3ba0 mm/memory.c:4234
 handle_pte_fault mm/memory.c:6052 [inline]
 __handle_mm_fault+0x152a/0x2a50 mm/memory.c:6195
 handle_mm_fault+0x589/0xd10 mm/memory.c:6364
 faultin_page mm/gup.c:1144 [inline]
 __get_user_pages+0x551/0x34a0 mm/gup.c:1446
 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1880
 __mm_populate+0x1d8/0x380 mm/gup.c:1983
page last free pid 9819 tgid 9809 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 free_unref_folios+0xa61/0x16b0 mm/page_alloc.c:2952
 folios_put_refs+0x56f/0x740 mm/swap.c:997
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x58f/0x1150 mm/shmem.c:1157
 shmem_truncate_range mm/shmem.c:1269 [inline]
 shmem_evict_inode+0x3a1/0xbe0 mm/shmem.c:1397
 evict+0x3e6/0x920 fs/inode.c:810
 iput_final fs/inode.c:1897 [inline]
 iput fs/inode.c:1923 [inline]
 iput+0x521/0x880 fs/inode.c:1909
 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:466
 __dentry_kill+0x1d0/0x600 fs/dcache.c:669
 dput.part.0+0x4b1/0x9b0 fs/dcache.c:911
 dput+0x1f/0x30 fs/dcache.c:901
 __fput+0x51c/0xb70 fs/file_table.c:476
 task_work_run+0x150/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x86f/0x2bf0 kernel/exit.c:961
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337

Memory state around the buggy address:
 ffff888068643780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888068643800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888068643880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff888068643900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888068643980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
hpfs: hpfs_map_sector(): read error
hpfs: hpfs_map_sector(): read error
hpfs: hpfs_map_sector(): read error
hpfs: hpfs_map_sector(): read error
hpfs: hpfs_map_4sectors(): unaligned read
hpfs: hpfs_map_4sectors(): unaligned read
hpfs: filesystem error: unable to find root dir