syzbot


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

Status: upstream: reported C repro on 2025/07/05 15:47
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+8573e4c1627aa4c9aa59@syzkaller.appspotmail.com
First crash: 5d00h, last: 4d17h
Bug presence (1)
Date Name Commit Repro Result
2025/07/06 upstream (ToT) d7b8f8e20813 C [report] KASAN: slab-out-of-bounds Read in dtInsertEntry
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream UBSAN: array-index-out-of-bounds in dtInsertEntry jfs 17 C inconclusive 1294 7m 279d 0/29 upstream: reported C repro on 2024/10/03 19:10
linux-6.1 KASAN: slab-out-of-bounds Read in dtInsertEntry origin:upstream 17 C 34 2d12h 92d 0/3 upstream: reported C repro on 2025/04/08 17:54
linux-4.19 general protection fault in dtInsertEntry 19 C error 4 971d 1018d 0/1 upstream: reported C repro on 2022/09/26 01:50
linux-5.15 BUG: unable to handle kernel paging request in dtInsertEntry missing-backport origin:upstream 17 C error 329 1d16h 764d 0/3 upstream: reported C repro on 2023/06/07 09:20
upstream general protection fault in dtInsertEntry jfs 17 C inconclusive 501 332d 457d 27/29 fixed on 2024/08/14 03:44
upstream BUG: unable to handle kernel NULL pointer dereference in dtInsertEntry jfs 19 C error done 29 524d 1018d 25/29 fixed on 2024/03/20 11:33
linux-6.1 BUG: unable to handle kernel paging request in dtInsertEntry 15 C error 17 319d 764d 0/3 auto-obsoleted due to no activity on 2024/12/03 11:36
linux-4.14 general protection fault in dtInsertEntry 2 C 3 862d 1018d 0/1 upstream: reported C repro on 2022/09/25 23:44

Sample crash report:
read_mapping_page failed!
ERROR: (device loop0): txCommit: 
read_mapping_page failed!
ERROR: (device loop0): txCommit: 
==================================================================
BUG: KASAN: slab-out-of-bounds in dtInsertEntry+0xe8b/0x13e0 fs/jfs/jfs_dtree.c:3753
Read of size 4 at addr ffff888060c1370c by task syz.0.16/5950

CPU: 0 PID: 5950 Comm: syz.0.16 Not tainted 6.6.95-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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/0x230 mm/kasan/report.c:475
 kasan_report+0x117/0x150 mm/kasan/report.c:588
 dtInsertEntry+0xe8b/0x13e0 fs/jfs/jfs_dtree.c:3753
 dtSplitPage+0x2a66/0x3b10 fs/jfs/jfs_dtree.c:1596
 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
 dtInsert+0x108f/0x5f40 fs/jfs/jfs_dtree.c:871
 jfs_symlink+0x719/0xe50 fs/jfs/namei.c:1019
 vfs_symlink+0x138/0x2b0 fs/namei.c:4473
 do_symlinkat+0x1b2/0x3f0 fs/namei.c:4499
 __do_sys_symlink fs/namei.c:4520 [inline]
 __se_sys_symlink fs/namei.c:4518 [inline]
 __x64_sys_symlink+0x7e/0x90 fs/namei.c:4518
 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: 0033:0x7f828478e929
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:00007ffd84558a48 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f82849b5fa0 RCX: 00007f828478e929
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000200000000080
RBP: 00007f8284810b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f82849b5fa0 R14: 00007f82849b5fa0 R15: 0000000000000002
 </TASK>

Allocated by task 5950:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3493 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3500 [inline]
 kmem_cache_alloc_lru+0x115/0x2e0 mm/slub.c:3516
 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]
 iget_locked+0x1ad/0x840 fs/inode.c:1359
 jfs_iget+0x24/0x3c0 fs/jfs/inode.c:29
 jfs_lookup+0x1c6/0x380 fs/jfs/namei.c:1467
 __lookup_slow+0x281/0x3b0 fs/namei.c:1694
 lookup_slow+0x53/0x70 fs/namei.c:1711
 walk_component+0x2be/0x3f0 fs/namei.c:2002
 lookup_last fs/namei.c:2459 [inline]
 path_lookupat+0x169/0x440 fs/namei.c:2483
 filename_lookup+0x1f4/0x510 fs/namei.c:2512
 user_path_at_empty+0x42/0x60 fs/namei.c:2909
 user_path_at include/linux/namei.h:57 [inline]
 __do_sys_chdir fs/open.c:551 [inline]
 __se_sys_chdir+0x95/0x290 fs/open.c:545
 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

The buggy address belongs to the object at ffff888060c12e40
 which belongs to the cache jfs_ip of size 2240
The buggy address is located 12 bytes to the right of
 allocated 2240-byte region [ffff888060c12e40, ffff888060c13700)

The buggy address belongs to the physical page:
page:ffffea0001830400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x60c10
head:ffffea0001830400 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888078d3cb01
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888142eb3b40 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800d000d 00000001ffffffff ffff888078d3cb01
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 5950, tgid 5950 (syz.0.16), ts 84736685196, free_ts 74014082038
 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:1876
 allocate_slab mm/slub.c:2023 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2076
 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
 __slab_alloc mm/slub.c:3329 [inline]
 __slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc_node mm/slub.c:3475 [inline]
 slab_alloc mm/slub.c:3493 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3500 [inline]
 kmem_cache_alloc_lru+0x1ae/0x2e0 mm/slub.c:3516
 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+0x52/0x6f0 fs/jfs/jfs_imap.c:426
 jfs_mount+0x73/0x860 fs/jfs/jfs_mount.c:87
 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
 vfree+0x1a6/0x320 mm/vmalloc.c:2860
 kcov_put kernel/kcov.c:438 [inline]
 kcov_close+0x2b/0x50 kernel/kcov.c:534
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x90b/0x23c0 kernel/exit.c:883
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 get_signal+0x12fc/0x1400 kernel/signal.c:2902
 arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 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
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888060c13600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888060c13680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888060c13700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff888060c13780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888060c13800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/05 23:27 linux-6.6.y 3f5b4c104b7d 4f67c4ae .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 dtInsertEntry
2025/07/05 15:46 linux-6.6.y 3f5b4c104b7d 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtInsertEntry
2025/07/05 15:46 linux-6.6.y 3f5b4c104b7d 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-out-of-bounds Read in dtInsertEntry
* Struck through repros no longer work on HEAD.