REISERFS (device loop2): Using tea hash to sort names
REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage.
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BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x635/0xab0
Read of size 48 at addr ffff8880876ffff0 by task syz-executor.2/8999

CPU: 0 PID: 8999 Comm: syz-executor.2 Not tainted 6.7.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0x163/0x540 mm/kasan/report.c:475
 kasan_report+0x142/0x170 mm/kasan/report.c:588
 kasan_check_range+0x27e/0x290 mm/kasan/generic.c:187
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 leaf_paste_in_buffer+0x635/0xab0
 leaf_copy_dir_entries+0x71e/0xc60 fs/reiserfs/lbalance.c:108
 leaf_copy_boundary_item+0xbbe/0x21b0 fs/reiserfs/lbalance.c:168
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0xd1a/0x2960 fs/reiserfs/lbalance.c:726
 leaf_shift_left+0xbe/0x430 fs/reiserfs/lbalance.c:750
 balance_leaf+0x15d1/0x12510 fs/reiserfs/do_balan.c:1409
 do_balance+0x30d/0x8f0 fs/reiserfs/do_balan.c:1888
 reiserfs_insert_item+0xace/0xc30 fs/reiserfs/stree.c:2260
 reiserfs_get_block+0x20ae/0x5130 fs/reiserfs/inode.c:868
 __block_write_begin_int+0x54d/0x1ad0 fs/buffer.c:2119
 reiserfs_write_begin+0x24d/0x520 fs/reiserfs/inode.c:2767
 generic_perform_write+0x31b/0x630 mm/filemap.c:3918
 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4039
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x792/0xb20 fs/read_write.c:584
 ksys_write+0x1a0/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fef6e67cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fef6f3f20c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fef6e79bf80 RCX: 00007fef6e67cae9
RDX: 000000000000fea7 RSI: 0000000020000240 RDI: 0000000000000006
RBP: 00007fef6e6c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fef6e79bf80 R15: 00007ffe5bd8f818
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00021dbfc0 refcount:2 mapcount:0 mapping:ffff88801b08e478 index:0x21c pfn:0x876ff
memcg:ffff88802a664000
aops:def_blk_aops ino:700002
flags: 0xfff00000008124(referenced|lru|active|private|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000008124 ffffea00020b7748 ffffea0000fa8948 ffff88801b08e478
raw: 000000000000021c ffff888077651488 00000002ffffffff ffff88802a664000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x148c48(GFP_NOFS|__GFP_NOFAIL|__GFP_COMP|__GFP_HARDWALL|__GFP_MOVABLE), pid 8999, tgid 8998 (syz-executor.2), ts 372166823827, free_ts 372039200146
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1544 [inline]
 get_page_from_freelist+0x33ea/0x3570 mm/page_alloc.c:3312
 __alloc_pages+0x255/0x680 mm/page_alloc.c:4568
 alloc_pages_mpol+0x3de/0x640 mm/mempolicy.c:2133
 alloc_pages mm/mempolicy.c:2204 [inline]
 folio_alloc+0x12a/0x330 mm/mempolicy.c:2211
 filemap_alloc_folio+0xde/0x500 mm/filemap.c:974
 __filemap_get_folio+0x431/0xbb0 mm/filemap.c:1918
 grow_dev_page fs/buffer.c:1041 [inline]
 grow_buffers fs/buffer.c:1106 [inline]
 __getblk_slow fs/buffer.c:1133 [inline]
 bdev_getblk+0x246/0x6d0 fs/buffer.c:1429
 __getblk include/linux/buffer_head.h:358 [inline]
 sb_getblk include/linux/buffer_head.h:364 [inline]
 get_empty_nodes+0x719/0xd90 fs/reiserfs/fix_node.c:890
 fix_nodes+0x261b/0x8ce0 fs/reiserfs/fix_node.c:2663
 reiserfs_paste_into_item+0x656/0x880 fs/reiserfs/stree.c:2129
 reiserfs_get_block+0x2250/0x5130 fs/reiserfs/inode.c:1069
 __block_write_begin_int+0x54d/0x1ad0 fs/buffer.c:2119
 reiserfs_write_begin+0x24d/0x520 fs/reiserfs/inode.c:2767
 generic_cont_expand_simple+0x18b/0x2a0 fs/buffer.c:2473
 reiserfs_setattr+0x57d/0x1140 fs/reiserfs/inode.c:3298
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1137 [inline]
 free_unref_page_prepare+0x931/0xa60 mm/page_alloc.c:2347
 free_unref_page_list+0x5a0/0x840 mm/page_alloc.c:2533
 release_pages+0x2117/0x2400 mm/swap.c:1042
 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu+0x34c/0x4e0 mm/mmu_gather.c:300
 tlb_finish_mmu+0xd4/0x1f0 mm/mmu_gather.c:392
 exit_mmap+0x4d3/0xc60 mm/mmap.c:3321
 __mmput+0x115/0x3c0 kernel/fork.c:1349
 exit_mm+0x21f/0x300 kernel/exit.c:567
 do_exit+0x9b7/0x2750 kernel/exit.c:858
 do_group_exit+0x206/0x2c0 kernel/exit.c:1021
 __do_sys_exit_group kernel/exit.c:1032 [inline]
 __se_sys_exit_group kernel/exit.c:1030 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1030
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
 ffff8880876fff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880876fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888087700000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888087700080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888087700100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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