syzbot


KASAN: slab-use-after-free Read in ntfs_iget5

Status: upstream: reported on 2025/08/19 13:23
Reported-by: syzbot+6d08037c33272de1e5a0@syzkaller.appspotmail.com
First crash: 214d, last: 1d10h
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Read in ntfs_iget5 ntfs3 19 C done done 3633 795d 1429d 25/29 fixed on 2024/03/20 11:33
upstream BUG: unable to handle kernel paging request in ntfs_iget5 ntfs3 8 1 678d 674d 0/29 auto-obsoleted due to no activity on 2024/08/10 16:42
linux-6.1 KASAN: use-after-free Read in ntfs_iget5 19 7 855d 1102d 0/3 auto-obsoleted due to no activity on 2024/02/25 08:58
linux-5.15 KASAN: use-after-free Read in ntfs_iget5 19 5 922d 1063d 0/3 auto-obsoleted due to no activity on 2023/12/20 11:31
linux-5.15 KASAN: slab-out-of-bounds Read in ntfs_iget5 19 31 212d 474d 0/3 auto-obsoleted due to no activity on 2025/11/29 13:33
linux-5.15 KASAN: use-after-free Read in ntfs_iget5 (2) 19 5 619d 719d 0/3 auto-obsoleted due to no activity on 2024/10/18 06:28
linux-5.15 KASAN: use-after-free Read in ntfs_iget5 (3) 19 4 10d 68d 0/3 upstream: reported on 2026/01/12 20:01
linux-6.1 KASAN: use-after-free Read in ntfs_iget5 (2) origin:upstream 19 C error 50 1d22h 722d 0/3 upstream: reported C repro on 2024/03/29 09:18

Sample crash report:
loop2: detected capacity change from 0 to 4096
==================================================================
BUG: KASAN: slab-use-after-free in ntfs_iget5+0x152/0x38a0 fs/ntfs3/inode.c:536
Read of size 8 at addr ffff88805b1f8ca0 by task syz.2.5103/17405

CPU: 1 PID: 17405 Comm: syz.2.5103 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
 ntfs_iget5+0x152/0x38a0 fs/ntfs3/inode.c:536
 ntfs_fill_super+0x28d8/0x4450 fs/ntfs3/super.c:1274
 get_tree_bdev+0x3f3/0x520 fs/super.c:1591
 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: 0033:0x7ff3f3f9da0a
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:00007ff3f4de1e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ff3f4de1ee0 RCX: 00007ff3f3f9da0a
RDX: 0000200000000080 RSI: 000020000001f740 RDI: 00007ff3f4de1ea0
RBP: 0000200000000080 R08: 00007ff3f4de1ee0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000020000001f740
R13: 00007ff3f4de1ea0 R14: 000000000001f74c R15: 0000200000000180
 </TASK>

Allocated by task 10983:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc_lru+0x111/0x2d0 mm/slub.c:3526
 alloc_inode_sb include/linux/fs.h:2946 [inline]
 reiserfs_alloc_inode+0x2a/0xc0 fs/reiserfs/super.c:642
 alloc_inode fs/inode.c:261 [inline]
 iget5_locked+0xa2/0x260 fs/inode.c:1314
 reiserfs_fill_super+0x11d7/0x23b0 fs/reiserfs/super.c:2053
 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

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 __call_rcu_common kernel/rcu/tree.c:2721 [inline]
 call_rcu+0x153/0x950 kernel/rcu/tree.c:2837
 destroy_inode fs/inode.c:316 [inline]
 evict+0x835/0x8d0 fs/inode.c:720
 reiserfs_fill_super+0x1479/0x23b0 fs/reiserfs/super.c:2078
 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

The buggy address belongs to the object at ffff88805b1f86a0
 which belongs to the cache reiser_inode_cache of size 1568
The buggy address is located 1536 bytes inside of
 freed 1568-byte region [ffff88805b1f86a0, ffff88805b1f8cc0)

The buggy address belongs to the physical page:
page:ffffea00016c7e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88805b1f93e0 pfn:0x5b1f8
head:ffffea00016c7e00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88802fdd0b01
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888140acac80 dead000000000122 0000000000000000
raw: ffff88805b1f93e0 0000000080130010 00000001ffffffff ffff88802fdd0b01
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d20d0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 9742, tgid 9741 (syz.2.1737), ts 277341232669, free_ts 244134154903
 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
 alloc_slab_page+0x5d/0x160 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5d/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc_lru+0x1aa/0x2d0 mm/slub.c:3526
 alloc_inode_sb include/linux/fs.h:2946 [inline]
 reiserfs_alloc_inode+0x2a/0xc0 fs/reiserfs/super.c:642
 alloc_inode fs/inode.c:261 [inline]
 iget5_locked+0xa2/0x260 fs/inode.c:1314
 reiserfs_fill_super+0x11d7/0x23b0 fs/reiserfs/super.c:2053
 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
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+0x32/0x2e0 mm/page_alloc.c:2458
 __slab_free+0x35a/0x400 mm/slub.c:3736
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11a/0x2d0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 locks_alloc_lock fs/locks.c:271 [inline]
 flock_lock_inode+0x22e/0x17f0 fs/locks.c:1039
 flock_lock_inode_wait fs/locks.c:2018 [inline]
 locks_lock_inode_wait+0x10e/0x480 fs/locks.c:2045
 locks_lock_file_wait include/linux/filelock.h:346 [inline]
 __do_sys_flock fs/locks.c:2115 [inline]
 __se_sys_flock+0x49a/0x600 fs/locks.c:2069
 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:
 ffff88805b1f8b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805b1f8c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805b1f8c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                               ^
 ffff88805b1f8d00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff88805b1f8d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/20 15:16 linux-6.6.y 4fc00fe35d46 ac6f1dff .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2026/03/06 00:10 linux-6.6.y 4fc00fe35d46 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2026/02/19 18:32 linux-6.6.y 7a137e9bfa0e c8d8c52d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2026/01/30 10:48 linux-6.6.y 2cf6f68313dc bfa73b7b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2026/01/23 09:44 linux-6.6.y cbb31f77b879 e2b1b6e6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2026/01/19 22:15 linux-6.6.y cbb31f77b879 572effc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2025/11/25 01:18 linux-6.6.y 1e89a1be4fe9 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2025/10/06 10:51 linux-6.6.y e617101e5626 91305dbe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2025/10/01 23:43 linux-6.6.y 147338df3487 267f56c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2025/08/20 02:21 linux-6.6.y bb9c90ab9c5a 79512909 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2025/08/19 13:22 linux-6.6.y bb9c90ab9c5a 254a27c1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in ntfs_iget5
2026/03/17 20:06 linux-6.6.y 4fc00fe35d46 c8810548 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in ntfs_iget5
2026/01/25 21:09 linux-6.6.y cbb31f77b879 55756628 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in ntfs_iget5
* Struck through repros no longer work on HEAD.