REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x631/0xab0
Read of size 48 at addr ffff88806e3e5ff0 by task syz-executor.0/4593

CPU: 0 PID: 4593 Comm: syz-executor.0 Not tainted 5.15.175-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 print_address_description+0x63/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
 kasan_check_range+0x27e/0x290 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x631/0xab0
 leaf_copy_dir_entries+0x71a/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+0xcd0/0x28a0 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+0xd479/0x12510 fs/reiserfs/do_balan.c:1393
 do_balance+0x309/0x8f0 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x1945/0x2560 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0xa12/0x15b0 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x638/0xda0 fs/reiserfs/inode.c:2318
 reiserfs_setattr+0xa4d/0xf90 fs/reiserfs/inode.c:3409
 notify_change+0xc6d/0xf50 fs/attr.c:505
 do_truncate+0x21c/0x300 fs/open.c:65
 handle_truncate fs/namei.c:3265 [inline]
 do_open fs/namei.c:3612 [inline]
 path_openat+0x28a3/0x2f20 fs/namei.c:3742
 do_filp_open+0x21c/0x460 fs/namei.c:3769
 do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_creat fs/open.c:1345 [inline]
 __se_sys_creat fs/open.c:1339 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1339
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc1cb25cca9
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:00007fc1ca5dd0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fc1cb38af80 RCX: 00007fc1cb25cca9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 00007fc1cb2a847e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fc1cb38af80 R15: 00007ffee6de1d28
 </TASK>

The buggy address belongs to the page:
page:ffffea0001b8f940 refcount:2 mapcount:0 mapping:ffff8881408fcf30 index:0x224 pfn:0x6e3e5
memcg:ffff88802c4e4000
aops:def_blk_aops ino:700000
flags: 0xfff00000002032(referenced|lru|active|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002032 ffffea0001b8f908 ffffea0001b8f848 ffff8881408fcf30
raw: 0000000000000224 ffff888073462000 00000002ffffffff ffff88802c4e4000
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 4593, ts 87670914016, free_ts 87346714151
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x3b78/0x3d40 mm/page_alloc.c:4192
 __alloc_pages+0x272/0x700 mm/page_alloc.c:5465
 __page_cache_alloc+0xd4/0x4a0 mm/filemap.c:1022
 pagecache_get_page+0xa91/0x1010 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+0x22a/0xaf0 fs/buffer.c:1336
 sb_getblk include/linux/buffer_head.h:361 [inline]
 get_empty_nodes+0x8c1/0xd70 fs/reiserfs/fix_node.c:890
 fix_nodes+0x2615/0x8c70 fs/reiserfs/fix_node.c:2662
 reiserfs_paste_into_item+0x65d/0x880 fs/reiserfs/stree.c:2130
 reiserfs_get_block+0x226a/0x5390 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x60b/0x1650 fs/buffer.c:2012
 reiserfs_write_begin+0x346/0x810 fs/reiserfs/inode.c:2790
 generic_cont_expand_simple+0x144/0x230 fs/buffer.c:2362
 reiserfs_setattr+0x3ff/0xf90 fs/reiserfs/inode.c:3319
 notify_change+0xc6d/0xf50 fs/attr.c:505
 do_truncate+0x21c/0x300 fs/open.c:65
 do_sys_ftruncate+0x2eb/0x390 fs/open.c:193
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+0xc34/0xcf0 mm/page_alloc.c:3317
 free_unref_page_list+0x1f7/0x8e0 mm/page_alloc.c:3433
 release_pages+0x1bb9/0x1f40 mm/swap.c:963
 __pagevec_release+0x80/0xf0 mm/swap.c:983
 pagevec_release include/linux/pagevec.h:81 [inline]
 shmem_undo_range+0x67a/0x1b50 mm/shmem.c:964
 shmem_truncate_range mm/shmem.c:1063 [inline]
 shmem_evict_inode+0x21b/0xa00 mm/shmem.c:1145
 evict+0x529/0x930 fs/inode.c:622
 __dentry_kill+0x436/0x650 fs/dcache.c:586
 dentry_kill+0xbb/0x290
 dput+0xd8/0x1a0 fs/dcache.c:893
 __fput+0x636/0x8e0 fs/file_table.c:288
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86

Memory state around the buggy address:
 ffff88806e3e5f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88806e3e5f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806e3e6000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88806e3e6080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806e3e6100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================