REISERFS (device loop0): journal params: device loop0, size 512, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using r5 hash to sort names
==================================================================
BUG: KASAN: use-after-free in reiserfs_get_unused_objectid+0x22d/0x480 fs/reiserfs/objectid.c:87
Read of size 250888 at addr ffff88806db40058 by task syz-executor.0/3891

CPU: 1 PID: 3891 Comm: syz-executor.0 Not tainted 5.15.174-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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
 memmove+0x25/0x60 mm/kasan/shadow.c:54
 reiserfs_get_unused_objectid+0x22d/0x480 fs/reiserfs/objectid.c:87
 reiserfs_new_inode+0x2b8/0x1d90 fs/reiserfs/inode.c:1952
 reiserfs_mkdir+0x5ac/0x8f0 fs/reiserfs/namei.c:845
 xattr_mkdir fs/reiserfs/xattr.c:76 [inline]
 create_privroot fs/reiserfs/xattr.c:889 [inline]
 reiserfs_xattr_init+0x348/0x730 fs/reiserfs/xattr.c:1012
 reiserfs_fill_super+0x226a/0x2690 fs/reiserfs/super.c:2179
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 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: 0033:0x7f6fc329605a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f6fc2615ee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6fc2615f80 RCX: 00007f6fc329605a
RDX: 0000000020000080 RSI: 0000000020000040 RDI: 00007f6fc2615f40
RBP: 0000000020000080 R08: 00007f6fc2615f80 R09: 0000000000008008
R10: 0000000000008008 R11: 0000000000000246 R12: 0000000020000040
R13: 00007f6fc2615f40 R14: 0000000000001138 R15: 00000000200000c0
 </TASK>

The buggy address belongs to the page:
page:ffffea0001b6d000 refcount:3 mapcount:0 mapping:ffff8880183308b0 index:0x10 pfn:0x6db40
memcg:ffff888019acc000
aops:def_blk_aops ino:700000
flags: 0xfff00000002022(referenced|active|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002022 0000000000000000 dead000000000122 ffff8880183308b0
raw: 0000000000000010 ffff888072e833a0 00000003ffffffff ffff888019acc000
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 3891, ts 72225354308, free_ts 15734979540
 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
 __bread_gfp+0x2a/0x390 fs/buffer.c:1381
 sb_bread include/linux/buffer_head.h:337 [inline]
 read_super_block+0x91/0x7e0 fs/reiserfs/super.c:1606
 reiserfs_fill_super+0x90a/0x2690 fs/reiserfs/super.c:1968
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 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
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+0x95/0x2d0 mm/page_alloc.c:3396
 free_contig_range+0x95/0xf0 mm/page_alloc.c:9384
 destroy_args+0xfe/0x980 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x40d/0x470 mm/debug_vm_pgtable.c:1331
 do_one_initcall+0x22b/0x7a0 init/main.c:1302
 do_initcall_level+0x157/0x210 init/main.c:1375
 do_initcalls+0x49/0x90 init/main.c:1391
 kernel_init_freeable+0x425/0x5c0 init/main.c:1615
 kernel_init+0x19/0x290 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff88806db43f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88806db43f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806db44000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88806db44080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806db44100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================