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KASAN: use-after-free Read in hpfs_get_ea

Status: upstream: reported C repro on 2025/07/27 17:30
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+91209a63bd6e8b2608e4@syzkaller.appspotmail.com
First crash: 152d, last: 4h12m
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2025/07/30 upstream (ToT) beb6c8326eb4 C [report] KASAN: use-after-free Read in hpfs_get_ea
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in hpfs_get_ea origin:upstream 19 C 372 2h51m 153d 0/3 upstream: reported C repro on 2025/07/26 19:47
upstream KASAN: use-after-free Read in hpfs_get_ea fs 19 C error 4730 48m 162d 0/29 upstream: reported C repro on 2025/07/17 19:14
linux-6.1 KASAN: use-after-free Read in hpfs_get_ea origin:upstream 19 C 729 45m 152d 0/3 upstream: reported C repro on 2025/07/27 17:28
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/08/31 05:47 1h46m bisect fix linux-6.6.y OK (0) job log log

Sample crash report:
         option from the mount to silence this warning.
=======================================================
hpfs: filesystem error: invalid number of hotfixes: 2066844986, used: 2066844985; already mounted read-only
hpfs: filesystem error: improperly stopped
hpfs: filesystem error: warning: spare dnodes used, try chkdsk
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+0x6f/0xb0 lib/string.c:288
Read of size 1 at addr ffff88806c5c98a6 by task syz.0.17/5946

CPU: 1 PID: 5946 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 strcmp+0x6f/0xb0 lib/string.c:288
 hpfs_get_ea+0x115/0xda0 fs/hpfs/ea.c:139
 hpfs_read_inode+0x19e/0x1010 fs/hpfs/inode.c:63
 hpfs_fill_super+0x12d5/0x1ec0 fs/hpfs/super.c:712
 mount_bdev+0x22b/0x2d0 fs/super.c:1643
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 do_new_mount+0x24b/0xa40 fs/namespace.c:3386
 do_mount fs/namespace.c:3726 [inline]
 __do_sys_mount fs/namespace.c:3935 [inline]
 __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc814b90e6a
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:00007ffc980ef498 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc980ef520 RCX: 00007fc814b90e6a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007ffc980ef4e0
RBP: 000020000000a000 R08: 00007ffc980ef520 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007ffc980ef4e0 R14: 0000000000009e15 R15: 0000200000000100
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001b17240 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6c5c9
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 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 5888, tgid 5888 (syz-executor), ts 89623413714, free_ts 89776496437
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 __folio_alloc+0x10/0x20 mm/page_alloc.c:4489
 vma_alloc_folio+0x47a/0x8f0 mm/mempolicy.c:2242
 alloc_page_vma include/linux/gfp.h:284 [inline]
 do_cow_fault mm/memory.c:4641 [inline]
 do_fault mm/memory.c:4755 [inline]
 do_pte_missing mm/memory.c:3688 [inline]
 handle_pte_fault mm/memory.c:5025 [inline]
 __handle_mm_fault mm/memory.c:5166 [inline]
 handle_mm_fault+0x1820/0x4920 mm/memory.c:5331
 do_user_addr_fault+0x738/0x12e0 arch/x86/mm/fault.c:1373
 handle_page_fault arch/x86/mm/fault.c:1465 [inline]
 exc_page_fault+0x67/0x110 arch/x86/mm/fault.c:1521
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
 release_pages+0x1fa0/0x2220 mm/swap.c:1022
 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
 exit_mmap+0x3f0/0xb50 mm/mmap.c:3315
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1da/0x2c0 kernel/exit.c:569
 do_exit+0x88e/0x23c0 kernel/exit.c:870
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 get_signal+0x12fc/0x1400 kernel/signal.c:2902
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87

Memory state around the buggy address:
 ffff88806c5c9780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806c5c9800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806c5c9880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff88806c5c9900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806c5c9980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (309):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/10 03:57 linux-6.6.y 0a805b6ea8cd 4e1406b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/07/27 17:53 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/27 09:15 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/26 19:28 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/25 17:57 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/24 13:04 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/24 11:44 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/24 03:22 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/19 04:31 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/18 23:49 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/13 17:26 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/13 02:11 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/04 16:50 linux-6.6.y 4791134e4aeb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/12/01 08:20 linux-6.6.y 1e89a1be4fe9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/11/23 09:42 linux-6.6.y 0a805b6ea8cd 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/11/10 02:58 linux-6.6.y 0a805b6ea8cd 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/11/03 12:57 linux-6.6.y 0a805b6ea8cd 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/11/01 23:30 linux-6.6.y e5bbb12db2c7 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/11/01 07:16 linux-6.6.y e5bbb12db2c7 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/31 06:22 linux-6.6.y e5bbb12db2c7 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/31 06:21 linux-6.6.y e5bbb12db2c7 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/27 12:34 linux-6.6.y 4a243110dc88 fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/27 04:09 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/25 10:06 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/25 04:04 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/24 08:35 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/23 21:33 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/23 15:15 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/23 14:07 linux-6.6.y f231f248323d c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/23 03:34 linux-6.6.y f231f248323d c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/22 01:40 linux-6.6.y f231f248323d 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/20 01:28 linux-6.6.y f231f248323d 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/19 09:00 linux-6.6.y 0bbbd97a442d 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/19 08:57 linux-6.6.y 0bbbd97a442d 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/16 12:01 linux-6.6.y 0bbbd97a442d 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/16 00:00 linux-6.6.y 0bbbd97a442d 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/15 16:40 linux-6.6.y 0bbbd97a442d 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/15 11:14 linux-6.6.y 0bbbd97a442d b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/14 20:08 linux-6.6.y 655054d2c3c1 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/14 18:58 linux-6.6.y 655054d2c3c1 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/14 01:25 linux-6.6.y 655054d2c3c1 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/14 00:37 linux-6.6.y 655054d2c3c1 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/13 07:38 linux-6.6.y 655054d2c3c1 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/12 22:48 linux-6.6.y 655054d2c3c1 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/12 02:20 linux-6.6.y e617101e5626 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/11 16:21 linux-6.6.y e617101e5626 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/11 00:18 linux-6.6.y e617101e5626 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/10 07:00 linux-6.6.y e617101e5626 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/10 00:13 linux-6.6.y e617101e5626 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/07/27 17:29 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2025/10/02 23:25 linux-6.6.y f34f16e5c632 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in hpfs_get_ea
2025/09/12 09:32 linux-6.6.y 60a9e718726f e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in hpfs_get_ea
* Struck through repros no longer work on HEAD.