KASAN: slab-out-of-bounds Read in dtSearch

Status: upstream: reported C repro on 2025/09/18 21:19
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+082a2bbdc6023d25075f@syzkaller.appspotmail.com
First crash: 309d, last: 49d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2026/06/05 linux-6.6.y (ToT) 924b4a879cbb C [report] KASAN: slab-out-of-bounds Read in dtSearch
2025/09/21 upstream (ToT) 2d5bd41a4505 C [report] KASAN: slab-out-of-bounds Read in dtSearch
2026/06/05 upstream (ToT) 06121e12c27a C Didn't crash
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Read in dtSearch jfs 19 C error done 33 935d 1398d 25/29 fixed on 2024/02/13 12:02
linux-4.14 KASAN: slab-out-of-bounds Read in dtSearch jfs 17 C 2 1241d 1399d 0/1 upstream: reported C repro on 2022/09/24 21:35
upstream KASAN: slab-use-after-free Read in dtSearch prio:high jfs 19 C inconclusive error 2308 100d 817d 0/29 upstream: reported C repro on 2024/04/29 00:37
linux-6.1 KASAN: slab-out-of-bounds Read in dtSearch (2) origin:upstream missing-backport 19 C error 79 54d 592d 0/3 upstream: reported C repro on 2024/12/09 07:03
linux-5.15 KASAN: slab-out-of-bounds Read in dtSearch origin:upstream 19 C error 204 1d06h 817d 0/3 upstream: reported C repro on 2024/04/28 11:04
linux-6.1 KASAN: slab-out-of-bounds Read in dtSearch 17 5 698d 761d 0/3 auto-obsoleted due to no activity on 2024/12/03 23:18
linux-4.19 KASAN: slab-out-of-bounds Read in dtSearch 17 C error 1 1399d 1399d 0/1 upstream: reported C repro on 2022/09/24 21:36
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2026/02/02 23:20 3m bisect fix linux-6.6.y error job log
2025/10/26 12:35 1h57m bisect fix linux-6.6.y OK (0) job log log

Sample crash report:
loop0: detected capacity change from 0 to 32768
==================================================================
BUG: KASAN: slab-out-of-bounds in ciCompare fs/jfs/jfs_dtree.c:3416 [inline]
BUG: KASAN: slab-out-of-bounds in dtSearch+0x16ab/0x21b0 fs/jfs/jfs_dtree.c:645
Read of size 1 at addr ffff88805fcfaa94 by task syz.0.18/5928

CPU: 0 PID: 5928 Comm: syz.0.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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
 ciCompare fs/jfs/jfs_dtree.c:3416 [inline]
 dtSearch+0x16ab/0x21b0 fs/jfs/jfs_dtree.c:645
 jfs_lookup+0x156/0x380 fs/jfs/namei.c:1459
 lookup_open fs/namei.c:3474 [inline]
 open_last_lookups fs/namei.c:3564 [inline]
 path_openat+0x10b8/0x3190 fs/namei.c:3794
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3824
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1421
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_creat fs/open.c:1514 [inline]
 __se_sys_creat fs/open.c:1508 [inline]
 __x64_sys_creat+0x90/0xb0 fs/open.c:1508
 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: 0033:0x7fba4778f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff16b887e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fba479e5fa0 RCX: 00007fba4778f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000580
RBP: 00007fba47813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fba479e5fa0 R14: 00007fba479e5fa0 R15: 0000000000000002
 </TASK>

The buggy address belongs to the object at ffff88805fcfa500
 which belongs to the cache jfs_ip of size 2240
The buggy address is located 1428 bytes inside of
 allocated 2240-byte region [ffff88805fcfa500, ffff88805fcfadc0)

The buggy address belongs to the physical page:
page:ffffea00017f3e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5fcf8
head:ffffea00017f3e00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888076bef101
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888018f28000 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800d000d 00000001ffffffff ffff888076bef101
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 5928, tgid 5928 (syz.0.18), ts 107975158823, free_ts 28289518628
 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
 alloc_slab_page+0x5d/0x170 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2081
 ___slab_alloc+0xc6d/0x1300 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+0x1ae/0x2e0 mm/slub.c:3526
 alloc_inode_sb include/linux/fs.h:2946 [inline]
 jfs_alloc_inode+0x28/0x60 fs/jfs/super.c:105
 alloc_inode fs/inode.c:261 [inline]
 new_inode_pseudo+0x63/0x1d0 fs/inode.c:1049
 new_inode+0x22/0x1b0 fs/inode.c:1075
 diReadSpecial+0x52/0x710 fs/jfs/jfs_imap.c:426
 jfs_mount+0x174/0x860 fs/jfs/jfs_mount.c:108
 jfs_fill_super+0x4e2/0xac0 fs/jfs/super.c:556
 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
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+0x32/0x2e0 mm/page_alloc.c:2429
 free_contig_range+0xa1/0x160 mm/page_alloc.c:6369
 destroy_args+0x80/0x850 mm/debug_vm_pgtable.c:1015
 debug_vm_pgtable+0x3cc/0x410 mm/debug_vm_pgtable.c:1400
 do_one_initcall+0x1fd/0x750 init/main.c:1250
 do_initcall_level+0x137/0x1f0 init/main.c:1312
 do_initcalls+0x69/0xd0 init/main.c:1328
 kernel_init_freeable+0x3d2/0x570 init/main.c:1565
 kernel_init+0x1d/0x1c0 init/main.c:1455
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Memory state around the buggy address:
 ffff88805fcfa980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805fcfaa00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88805fcfaa80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88805fcfab00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805fcfab80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/03 23:12 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtSearch
2025/09/19 02:56 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtSearch
2025/09/19 01:47 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtSearch
2025/09/19 00:39 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtSearch
2025/09/18 23:32 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtSearch
2025/09/18 22:28 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtSearch
2026/01/03 22:14 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 dtSearch
2025/09/18 21:19 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 dtSearch
2025/12/12 08:40 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dtSearch
2025/11/11 22:41 linux-6.6.y 0a805b6ea8cd 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan UBSAN: array-index-out-of-bounds in dtSearch
2025/11/09 15:09 linux-6.6.y 0a805b6ea8cd 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan UBSAN: array-index-out-of-bounds in dtSearch
* Struck through repros no longer work on HEAD.