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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: 254d, last: 22h39m
Fix bisection: failed (error log, bisect log)
  
▶ ▼ 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 487 1d13h 255d 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 7378 54m 264d 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 924 12h07m 254d 0/3 upstream: reported C repro on 2025/07/27 17:28
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2026/03/18 03:14 4m bisect fix linux-6.6.y error job log
2025/08/31 05:47 1h46m bisect fix linux-6.6.y OK (0) job log log

Sample crash report:
hpfs: filesystem error: improperly stopped; already mounted read-only
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+0x6b/0xb0 lib/string.c:288
Read of size 1 at addr ffff8880617368a6 by task syz.0.17/5924

CPU: 1 PID: 5924 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 strcmp+0x6b/0xb0 lib/string.c:288
 hpfs_get_ea+0x135/0xed0 fs/hpfs/ea.c:139
 hpfs_read_inode+0x1a7/0x1050 fs/hpfs/inode.c:63
 hpfs_fill_super+0x135e/0x1fe0 fs/hpfs/super.c:712
 mount_bdev+0x221/0x2d0 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+0x2e7/0x3d0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9f4c79da8a
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:00007ffc3d5e5f68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc3d5e5ff0 RCX: 00007f9f4c79da8a
RDX: 0000200000000080 RSI: 0000200000009ec0 RDI: 00007ffc3d5e5fb0
RBP: 0000200000000080 R08: 00007ffc3d5e5ff0 R09: 0000000003a00041
R10: 0000000003a00041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007ffc3d5e5fb0 R14: 0000000000009e3e R15: 0000200000000040
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000185cd80 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x61736
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea0001b485c8 ffffea0001b28708 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 5923, tgid 5923 (modprobe), ts 99191321933, free_ts 99197438783
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581
 prep_new_page mm/page_alloc.c:1588 [inline]
 get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4500
 __folio_alloc+0x10/0x20 mm/page_alloc.c:4532
 vma_alloc_folio+0x47a/0x8f0 mm/mempolicy.c:2240
 wp_page_copy mm/memory.c:3094 [inline]
 do_wp_page+0x1272/0x35f0 mm/memory.c:3469
 handle_pte_fault mm/memory.c:5063 [inline]
 __handle_mm_fault mm/memory.c:5188 [inline]
 handle_mm_fault+0x135d/0x4c00 mm/memory.c:5353
 do_user_addr_fault+0xac8/0x12c0 arch/x86/mm/fault.c:1322
 handle_page_fault arch/x86/mm/fault.c:1463 [inline]
 exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
 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:1181 [inline]
 free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2504
 release_pages+0x1f7a/0x2200 mm/swap.c:1022
 tlb_batch_pages_flush mm/mmu_gather.c:99 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:294 [inline]
 tlb_flush_mmu+0x379/0x510 mm/mmu_gather.c:301
 tlb_finish_mmu+0xf9/0x220 mm/mmu_gather.c:425
 exit_mmap+0x428/0xb90 mm/mmap.c:3315
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1f2/0x2c0 kernel/exit.c:569
 do_exit+0x8dd/0x2460 kernel/exit.c:870
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 __do_sys_exit_group kernel/exit.c:1035 [inline]
 __se_sys_exit_group kernel/exit.c:1033 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888061736780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888061736800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888061736880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff888061736900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888061736980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (355):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/29 18:41 linux-6.6.y c09fbcd31ae6 b5ceaad2 .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
2025/11/10 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
2026/04/06 23:44 linux-6.6.y 80de0a958133 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2026/03/31 09:19 linux-6.6.y c09fbcd31ae6 aeea1c72 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2026/03/31 05:14 linux-6.6.y c09fbcd31ae6 d0af506e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2026/03/29 18:19 linux-6.6.y c09fbcd31ae6 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2026/02/16 02:42 linux-6.6.y 1b4ef5214f17 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2026/02/05 18:31 linux-6.6.y 2cf6f68313dc 4936e85c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: use-after-free Read in hpfs_get_ea
2026/01/11 14:58 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
2026/01/08 18:35 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
2026/01/08 18:31 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
2026/01/07 11:29 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
2026/01/07 10:19 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
2026/01/06 20:58 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
2026/01/06 19:21 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
2026/01/02 11:28 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
2025/12/31 20:35 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
2025/12/30 01:25 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
2025/12/29 04:43 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
2025/12/28 21:42 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
2025/12/27 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
2025/07/27 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
2026/03/30 01:52 linux-6.6.y c09fbcd31ae6 b5ceaad2 .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
2026/01/09 23:52 linux-6.6.y 5fa4793a2d2d d6526ea3 .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
2026/01/08 19:02 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: out-of-bounds 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
* Struck through repros no longer work on HEAD.