UBSAN: array-index-out-of-bounds in dtSplitPage

Status: upstream: reported C repro on 2024/12/29 06:57
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+63c40a3ef45fce944739@syzkaller.appspotmail.com
First crash: 599d, last: 1d13h
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2025/10/17 upstream (ToT) 6f3b6e91f720 C [report] KASAN: slab-out-of-bounds Read in dtSplitPage
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 UBSAN: array-index-out-of-bounds in dtSplitPage origin:upstream 22 syz, C 163 3d03h 425d 0/2 upstream: reported C repro on 2025/06/20 22:01
upstream KASAN: slab-use-after-free Write in dtSplitPage prio:high jfs 22 syz, C inconclusive 8023 17h54m 612d 0/29 upstream: reported C repro on 2024/12/15 23:15
linux-6.1 UBSAN: array-index-out-of-bounds in dtSplitPage origin:upstream 22 syz, C 290 3d10h 598d 0/3 upstream: reported C repro on 2024/12/30 07:45
▶ ▼ Last patch testing requests (8)
Created Duration User Patch Repo Result
2026/07/23 15:48 16m retest repro linux-5.15.y report log
2026/05/29 02:25 16m retest repro linux-5.15.y report log
2026/05/29 02:25 25m retest repro linux-5.15.y report log
2026/02/08 18:45 13m retest repro linux-5.15.y report log
2026/02/08 18:45 10m retest repro linux-5.15.y report log
2026/02/08 18:45 11m retest repro linux-5.15.y report log
2025/10/27 08:49 10m retest repro linux-5.15.y report log
2025/10/11 10:33 39m retest repro linux-5.15.y report log

Sample crash report:
loop0: detected capacity change from 0 to 32768
==================================================================
BUG: KASAN: use-after-free in dtMoveEntry fs/jfs/jfs_dtree.c:4232 [inline]
BUG: KASAN: use-after-free in dtSplitPage+0x1a2c/0x3160 fs/jfs/jfs_dtree.c:1561
Write of size 1 at addr ffff8880788cd000 by task syz.0.17/4309

CPU: 0 PID: 4309 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 dtMoveEntry fs/jfs/jfs_dtree.c:4232 [inline]
 dtSplitPage+0x1a2c/0x3160 fs/jfs/jfs_dtree.c:1561
 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
 dtInsert+0x1074/0x57e0 fs/jfs/jfs_dtree.c:871
 jfs_rename+0x89a/0x1910 fs/jfs/namei.c:1224
 vfs_rename+0xd57/0x10f0 fs/namei.c:4840
 do_renameat2+0x9e9/0xf70 fs/namei.c:4993
 __do_sys_rename fs/namei.c:5039 [inline]
 __se_sys_rename fs/namei.c:5037 [inline]
 __x64_sys_rename+0x82/0x90 fs/namei.c:5037
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa4f079c0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007ffca39ec4b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007fa4f0a23fa0 RCX: 00007fa4f079c0d9
RDX: 0000000000000000 RSI: 0000200000000f40 RDI: 00002000000003c0
RBP: 00007fa4f0833024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa4f0a23fac R14: 00007fa4f0a23fa0 R15: 00007fa4f0a23fa0
 </TASK>

Allocated by task 4108:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x92/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc+0x15d/0x280 mm/slub.c:3238
 vm_area_alloc+0x20/0xe0 kernel/fork.c:351
 __mmap_region mm/mmap.c:1782 [inline]
 mmap_region+0xbd2/0x1730 mm/mmap.c:2933
 do_mmap+0x801/0xe30 mm/mmap.c:1586
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:551
 ksys_mmap_pgoff+0x4e2/0x790 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 4108:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 remove_vma mm/mmap.c:188 [inline]
 exit_mmap+0x502/0x640 mm/mmap.c:3227
 __mmput+0x115/0x390 kernel/fork.c:1128
 exit_mm+0x632/0x7b0 kernel/exit.c:557
 do_exit+0x5b8/0x2110 kernel/exit.c:877
 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff8880788cd000
 which belongs to the cache vm_area_struct of size 200
The buggy address is located 0 bytes inside of
 200-byte region [ffff8880788cd000, ffff8880788cd0c8)
The buggy address belongs to the page:
page:ffffea0001e23340 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x788cd
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888140007a00
raw: 0000000000000000 00000000000f000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 4108, ts 58975893210, free_ts 58966849048
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc+0xf0/0x280 mm/slub.c:3238
 vm_area_alloc+0x20/0xe0 kernel/fork.c:351
 __mmap_region mm/mmap.c:1782 [inline]
 mmap_region+0xbd2/0x1730 mm/mmap.c:2933
 do_mmap+0x801/0xe30 mm/mmap.c:1586
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:551
 ksys_mmap_pgoff+0x4e2/0x790 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page_list+0x119/0x830 mm/page_alloc.c:3433
 release_pages+0x185f/0x1bd0 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:50 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:241 [inline]
 tlb_flush_mmu mm/mmu_gather.c:248 [inline]
 tlb_finish_mmu+0x1b4/0x370 mm/mmu_gather.c:371
 exit_mmap+0x3d0/0x640 mm/mmap.c:3218
 __mmput+0x115/0x390 kernel/fork.c:1128
 exit_mm+0x632/0x7b0 kernel/exit.c:557
 do_exit+0x5b8/0x2110 kernel/exit.c:877
 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff8880788ccf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880788ccf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880788cd000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880788cd080: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc
 ffff8880788cd100: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (142):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/17 05:43 linux-5.15.y aabd761612db 746171ee .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan KASAN: use-after-free Write in dtSplitPage
2026/01/23 07:41 linux-5.15.y 9eec9a14ee10 82c9c083 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/10/12 21:35 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/06/24 11:37 linux-5.15.y 1c700860e8bc e2f27c35 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in dtSplitPage
2025/04/18 01:47 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan UBSAN: array-index-out-of-bounds in dtSplitPage
2025/03/16 10:26 linux-5.15.y 0c935c049b5c e2826670 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan UBSAN: array-index-out-of-bounds in dtSplitPage
2024/12/29 06:56 linux-5.15.y 91786f140358 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan UBSAN: array-index-out-of-bounds in dtSplitPage
2026/08/19 05:20 linux-5.15.y aabd761612db 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Write in dtSplitPage
2026/08/17 04:24 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Write in dtSplitPage
2026/04/12 07:04 linux-5.15.y 91d48252ad4b 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/03/29 08:06 linux-5.15.y 91d48252ad4b b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/03/22 18:07 linux-5.15.y 91d48252ad4b 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/03/11 08:38 linux-5.15.y 91d48252ad4b 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/03/08 20:23 linux-5.15.y 91d48252ad4b 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/02/24 17:38 linux-5.15.y 3330a8d33e08 96b1aa46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/02/23 16:47 linux-5.15.y 3330a8d33e08 6beca497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/02/21 19:27 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/02/15 04:00 linux-5.15.y e45d5d41c134 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/25 16:59 linux-5.15.y 9eec9a14ee10 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/23 03:35 linux-5.15.y 9eec9a14ee10 82c9c083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/15 14:46 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/15 08:42 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/15 06:02 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/13 03:57 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/09 21:18 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/09 13:04 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/07 03:26 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/06 23:21 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/02 06:38 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2026/01/01 12:07 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/12/30 23:33 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/12/28 08:26 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/12/21 05:04 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/12/15 05:04 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/12/11 02:34 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/11/28 02:11 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/11/26 21:35 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Write in dtSplitPage
2025/11/12 04:33 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/11/12 00:09 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/11/10 02:57 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/11/09 14:24 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/11/02 07:03 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/10/12 21:07 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/09/23 10:07 linux-5.15.y 43bb85222e53 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/09/19 22:04 linux-5.15.y 43bb85222e53 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/09/19 22:04 linux-5.15.y 43bb85222e53 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/09/19 08:06 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/09/18 10:37 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/09/17 23:46 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in dtSplitPage
2025/06/11 22:52 linux-5.15.y 1c700860e8bc 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Write in dtSplitPage
2025/07/31 12:22 linux-5.15.y c79648372d02 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in dtSplitPage
* Struck through repros no longer work on HEAD.