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BUG: KASAN: slab-out-of-bounds in dtSplitPage+0x12c6/0x3b20 fs/jfs/jfs_dtree.c:-1
Read of size 1 at addr ffff88804dd2f695 by task syz.4.3426/17767

CPU: 1 UID: 0 PID: 17767 Comm: syz.4.3426 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 dtSplitPage+0x12c6/0x3b20 fs/jfs/jfs_dtree.c:-1
 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
 dtInsert+0x109b/0x5f40 fs/jfs/jfs_dtree.c:871
 jfs_create+0x6c8/0xa80 fs/jfs/namei.c:137
 lookup_open fs/namei.c:4409 [inline]
 open_last_lookups fs/namei.c:4509 [inline]
 path_openat+0x190f/0x3d90 fs/namei.c:4753
 do_filp_open+0x1fa/0x410 fs/namei.c:4783
 do_sys_openat2+0x121/0x1c0 fs/open.c:1432
 do_sys_open fs/open.c:1447 [inline]
 __do_sys_openat fs/open.c:1463 [inline]
 __se_sys_openat fs/open.c:1458 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1458
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0595f8f749
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:00007f05941d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f05961e6090 RCX: 00007f0595f8f749
RDX: 0000000000183042 RSI: 0000200000000740 RDI: ffffffffffffff9c
RBP: 00007f0596013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000015 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f05961e6128 R14: 00007f05961e6090 R15: 00007ffdd7590fd8
 </TASK>

Allocated by task 17745:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4948 [inline]
 slab_alloc_node mm/slub.c:5258 [inline]
 kmem_cache_alloc_lru_noprof+0x36c/0x6e0 mm/slub.c:5277
 jfs_alloc_inode+0x28/0x70 fs/jfs/super.c:105
 alloc_inode+0x6a/0x1b0 fs/inode.c:346
 iget_locked+0x135/0x6c0 fs/inode.c:1473
 jfs_iget+0x24/0x470 fs/jfs/inode.c:29
 jfs_lookup+0x1c5/0x380 fs/jfs/namei.c:1469
 __lookup_slow+0x297/0x3d0 fs/namei.c:1855
 lookup_slow+0x53/0x70 fs/namei.c:1872
 walk_component+0x2d2/0x400 fs/namei.c:2190
 lookup_last fs/namei.c:2691 [inline]
 path_lookupat+0x163/0x430 fs/namei.c:2715
 filename_lookup+0x212/0x570 fs/namei.c:2744
 user_path_at+0x3a/0x60 fs/namei.c:3536
 __do_sys_chdir fs/open.c:558 [inline]
 __se_sys_chdir+0x91/0x280 fs/open.c:552
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88804dd2ede0
 which belongs to the cache jfs_ip of size 2216
The buggy address is located 13 bytes to the right of
 allocated 2216-byte region [ffff88804dd2ede0, ffff88804dd2f688)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88804dd2a4a0 pfn:0x4dd28
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88807616ac01
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801c7fca00 dead000000000122 0000000000000000
raw: ffff88804dd2a4a0 00000000800d0009 00000000f5000000 ffff88807616ac01
head: 00fff00000000040 ffff88801c7fca00 dead000000000122 0000000000000000
head: ffff88804dd2a4a0 00000000800d0009 00000000f5000000 ffff88807616ac01
head: 00fff00000000003 ffffea0001374a01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0xd2050(__GFP_RECLAIMABLE|__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 7043, tgid 7041 (syz.4.274), ts 178522640758, free_ts 119539770027
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
 prep_new_page mm/page_alloc.c:1854 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xf56/0x1990 mm/slub.c:4651
 __slab_alloc+0x65/0x100 mm/slub.c:4774
 __slab_alloc_node mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:5246 [inline]
 kmem_cache_alloc_lru_noprof+0x3fe/0x6e0 mm/slub.c:5277
 jfs_alloc_inode+0x28/0x70 fs/jfs/super.c:105
 alloc_inode+0x6a/0x1b0 fs/inode.c:346
 new_inode+0x22/0x170 fs/inode.c:1175
 diReadSpecial+0x52/0x710 fs/jfs/jfs_imap.c:426
 jfs_mount+0x3d1/0x870 fs/jfs/jfs_mount.c:166
 jfs_fill_super+0x6bc/0xd80 fs/jfs/super.c:523
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1699
 vfs_get_tree+0x92/0x2b0 fs/super.c:1759
page last free pid 5827 tgid 5827 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 free_unref_folios+0xd22/0x1470 mm/page_alloc.c:3000
 folios_put_refs+0x584/0x670 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x49e/0x1490 mm/shmem.c:1148
 shmem_truncate_range mm/shmem.c:1260 [inline]
 shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1389
 evict+0x5f4/0xae0 fs/inode.c:837
 do_unlinkat+0x340/0x560 fs/namei.c:5412
 __do_sys_unlink fs/namei.c:5443 [inline]
 __se_sys_unlink fs/namei.c:5441 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:5441
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88804dd2f580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804dd2f600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804dd2f680: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88804dd2f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88804dd2f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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