REISERFS (device loop9): Using tea hash to sort names
REISERFS (device loop9): Created .reiserfs_priv - reserved for xattr storage.
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BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x615/0xab0 fs/reiserfs/lbalance.c:-1
Read of size 48 at addr ffff88805265fff0 by task syz.9.518/8581

CPU: 1 PID: 8581 Comm: syz.9.518 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x235/0x290 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x615/0xab0 fs/reiserfs/lbalance.c:-1
 leaf_copy_dir_entries+0x56c/0x8f0 fs/reiserfs/lbalance.c:108
 leaf_copy_boundary_item+0xb8c/0x2190 fs/reiserfs/lbalance.c:168
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0x85f/0xe00 fs/reiserfs/lbalance.c:726
 balance_leaf_when_delete_left fs/reiserfs/do_balan.c:167 [inline]
 balance_leaf_when_delete fs/reiserfs/do_balan.c:272 [inline]
 balance_leaf+0xc2bd/0x10ec0 fs/reiserfs/do_balan.c:1393
 do_balance+0x318/0x930 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x154d/0x1fa0 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0xa09/0x1390 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x666/0xe40 fs/reiserfs/inode.c:2318
 reiserfs_setattr+0xab3/0x1090 fs/reiserfs/inode.c:3409
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x1ac/0x240 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xf2/0x1c0 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa23b2f5799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa23954f028 EFLAGS: 00000246
 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007fa23b56efa0 RCX: 00007fa23b2f5799
RDX: 0000000000000000 RSI: 00000000000000d2 RDI: 0000200000000100
RBP: 00007fa23b38bbd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa23b56f038 R14: 00007fa23b56efa0 R15: 00007ffe4d13a7d8
 </TASK>

The buggy address belongs to the page:
page:ffffea00014997c0 refcount:2 mapcount:0 mapping:ffff888140914370 index:0x220 pfn:0x5265f
memcg:ffff888076434000
aops:def_blk_aops ino:700009
flags: 0xfff00000002032(referenced|lru|active|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002032 ffffea0001491788 ffffea0001413e08 ffff888140914370
raw: 0000000000000220 ffff888076299ae0 00000002ffffffff ffff888076434000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 8581, ts 285898017622, free_ts 285831982972
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 __page_cache_alloc+0xce/0x440 mm/filemap.c:1022
 pagecache_get_page+0x9b6/0xf10 mm/filemap.c:1940
 find_or_create_page include/linux/pagemap.h:420 [inline]
 grow_dev_page fs/buffer.c:949 [inline]
 grow_buffers fs/buffer.c:1014 [inline]
 __getblk_slow fs/buffer.c:1041 [inline]
 __getblk_gfp+0x247/0xb60 fs/buffer.c:1336
 sb_getblk include/linux/buffer_head.h:361 [inline]
 get_empty_nodes+0x56a/0x920 fs/reiserfs/fix_node.c:890
 fix_nodes+0x1ebc/0x8340 fs/reiserfs/fix_node.c:2662
 reiserfs_paste_into_item+0x60b/0x810 fs/reiserfs/stree.c:2130
 reiserfs_get_block+0x1c3a/0x42a0 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x565/0x15d0 fs/buffer.c:2012
 reiserfs_write_begin+0x34b/0x810 fs/reiserfs/inode.c:2790
 generic_cont_expand_simple+0xf0/0x1a0 fs/buffer.c:2362
 reiserfs_setattr+0x3ee/0x1090 fs/reiserfs/inode.c:3319
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x1ac/0x240 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page_list+0x119/0x820 mm/page_alloc.c:3433
 release_pages+0x186c/0x1be0 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x176/0x300 mm/mmu_gather.c:338
 unmap_region+0x344/0x3b0 mm/mmap.c:2669
 __do_munmap+0x9f8/0xdf0 mm/mmap.c:2899
 __vm_munmap+0x140/0x240 mm/mmap.c:2952
 __do_sys_munmap mm/mmap.c:2978 [inline]
 __se_sys_munmap mm/mmap.c:2974 [inline]
 __x64_sys_munmap+0x67/0x70 mm/mmap.c:2974
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88805265ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88805265ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888052660000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888052660080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888052660100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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