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BUG: KASAN: slab-out-of-bounds in dtInsertEntry+0xe9a/0x1430 fs/jfs/jfs_dtree.c:3765
Read of size 4 at addr ffff88804ecf08cc by task syz.2.60/6450

CPU: 0 UID: 0 PID: 6450 Comm: syz.2.60 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 dtInsertEntry+0xe9a/0x1430 fs/jfs/jfs_dtree.c:3765
 dtSplitPage+0x2a83/0x3b20 fs/jfs/jfs_dtree.c:1596
 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:3717 [inline]
 open_last_lookups fs/namei.c:3816 [inline]
 path_openat+0x14f4/0x3830 fs/namei.c:4052
 do_filp_open+0x1fa/0x410 fs/namei.c:4082
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_open fs/open.c:1460 [inline]
 __se_sys_open fs/open.c:1456 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1456
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fab4e38e929
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:00007fab4f1b0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fab4e5b5fa0 RCX: 00007fab4e38e929
RDX: 0000000000000000 RSI: 000000000006827e RDI: 0000200000000180
RBP: 00007fab4e410b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fab4e5b5fa0 R15: 00007fffca5c12b8
 </TASK>

Allocated by task 6450:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_lru_noprof+0x1c6/0x3d0 mm/slub.c:4216
 jfs_alloc_inode+0x28/0x70 fs/jfs/super.c:105
 alloc_inode+0x67/0x1b0 fs/inode.c:346
 iget_locked+0xf0/0x570 fs/inode.c:1439
 jfs_iget+0x24/0x3e0 fs/jfs/inode.c:29
 jfs_lookup+0x1c5/0x380 fs/jfs/namei.c:1469
 __lookup_slow+0x297/0x3d0 fs/namei.c:1817
 lookup_slow+0x53/0x70 fs/namei.c:1834
 walk_component+0x2d2/0x400 fs/namei.c:2138
 lookup_last fs/namei.c:2639 [inline]
 path_lookupat+0x163/0x430 fs/namei.c:2663
 filename_lookup+0x212/0x570 fs/namei.c:2692
 user_path_at+0x3a/0x60 fs/namei.c:3136
 __do_sys_chdir fs/open.c:560 [inline]
 __se_sys_chdir+0x91/0x280 fs/open.c:554
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88804ecf0000
 which belongs to the cache jfs_ip of size 2232
The buggy address is located 20 bytes to the right of
 allocated 2232-byte region [ffff88804ecf0000, ffff88804ecf08b8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4ecf0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888076aa2b01
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801f3073c0 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800d000d 00000000f5000000 ffff888076aa2b01
head: 00fff00000000040 ffff88801f3073c0 dead000000000122 0000000000000000
head: 0000000000000000 00000000800d000d 00000000f5000000 ffff888076aa2b01
head: 00fff00000000003 ffffea00013b3c01 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 6450, tgid 6449 (syz.2.60), ts 108596816844, free_ts 97627292697
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 kmem_cache_alloc_lru_noprof+0x288/0x3d0 mm/slub.c:4216
 jfs_alloc_inode+0x28/0x70 fs/jfs/super.c:105
 alloc_inode+0x67/0x1b0 fs/inode.c:346
 iget_locked+0xf0/0x570 fs/inode.c:1439
 jfs_iget+0x24/0x3e0 fs/jfs/inode.c:29
 jfs_lookup+0x1c5/0x380 fs/jfs/namei.c:1469
 __lookup_slow+0x297/0x3d0 fs/namei.c:1817
 lookup_slow+0x53/0x70 fs/namei.c:1834
 walk_component+0x2d2/0x400 fs/namei.c:2138
 lookup_last fs/namei.c:2639 [inline]
 path_lookupat+0x163/0x430 fs/namei.c:2663
page last free pid 6210 tgid 6209 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_pages_ok+0xa3b/0xc10 mm/page_alloc.c:1424
 __folio_put+0x21b/0x2c0 mm/swap.c:112
 folio_put include/linux/mm.h:1356 [inline]
 free_large_kmalloc+0x145/0x200 mm/slub.c:4768
 btree_bounce_free fs/bcachefs/btree_io.c:115 [inline]
 bch2_btree_node_read_done+0x36df/0x5520 fs/bcachefs/btree_io.c:1296
 btree_node_read_work+0x40e/0xe60 fs/bcachefs/btree_io.c:1440
 bch2_btree_node_read+0x887/0x2a00 fs/bcachefs/btree_io.c:-1
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1906 [inline]
 bch2_btree_root_read+0x5f0/0x760 fs/bcachefs/btree_io.c:1928
 read_btree_roots+0x2c6/0x840 fs/bcachefs/recovery.c:615
 bch2_fs_recovery+0x261f/0x3a50 fs/bcachefs/recovery.c:1006
 bch2_fs_start+0xaaf/0xda0 fs/bcachefs/super.c:1213
 bch2_fs_get_tree+0xb39/0x1520 fs/bcachefs/fs.c:2488
 vfs_get_tree+0x92/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3902
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88804ecf0780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804ecf0800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804ecf0880: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
                                              ^
 ffff88804ecf0900: fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb
 ffff88804ecf0980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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