REISERFS (device loop4): Using r5 hash to sort names
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BUG: KASAN: use-after-free in reiserfs_get_unused_objectid+0x231/0x490 fs/reiserfs/objectid.c:87
Read of size 250888 at addr ffff88803b267058 by task syz-executor.4/23051

CPU: 1 PID: 23051 Comm: syz-executor.4 Not tainted 6.3.0-rc3-syzkaller-00031-g1e760fa3596e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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:319 [inline]
 print_report+0x163/0x540 mm/kasan/report.c:430
 kasan_report+0x176/0x1b0 mm/kasan/report.c:536
 kasan_check_range+0x283/0x290 mm/kasan/generic.c:187
 __asan_memmove+0x29/0x70 mm/kasan/shadow.c:94
 reiserfs_get_unused_objectid+0x231/0x490 fs/reiserfs/objectid.c:87
 reiserfs_new_inode+0x2bc/0x1da0 fs/reiserfs/inode.c:1944
 reiserfs_mkdir+0x5b0/0x8f0 fs/reiserfs/namei.c:845
 xattr_mkdir fs/reiserfs/xattr.c:76 [inline]
 create_privroot fs/reiserfs/xattr.c:882 [inline]
 reiserfs_xattr_init+0x34c/0x730 fs/reiserfs/xattr.c:1005
 reiserfs_fill_super+0x2207/0x2620 fs/reiserfs/super.c:2175
 mount_bdev+0x271/0x3a0 fs/super.c:1380
 legacy_get_tree+0xef/0x190 fs/fs_context.c:610
 vfs_get_tree+0x8c/0x270 fs/super.c:1510
 do_new_mount+0x28f/0xae0 fs/namespace.c:3042
 do_mount fs/namespace.c:3385 [inline]
 __do_sys_mount fs/namespace.c:3594 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3571
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fcb0928d62a
Code: 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcb0a0c8f88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000001138 RCX: 00007fcb0928d62a
RDX: 0000000020000080 RSI: 0000000020000040 RDI: 00007fcb0a0c8fe0
RBP: 00007fcb0a0c9020 R08: 00007fcb0a0c9020 R09: 0000000000008008
R10: 0000000000008008 R11: 0000000000000202 R12: 0000000020000080
R13: 0000000020000040 R14: 00007fcb0a0c8fe0 R15: 00000000200000c0
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0000ec99c0 refcount:2 mapcount:0 mapping:ffff88801c12dff8 index:0x10 pfn:0x3b267
memcg:ffff888017db4000
aops:def_blk_aops ino:700004
flags: 0xfff00000002032(referenced|lru|active|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002032 ffffea0000ec9988 ffff88807b77f030 ffff88801c12dff8
raw: 0000000000000010 ffff888034b02828 00000002ffffffff ffff888017db4000
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 23051, tgid 23046 (syz-executor.4), ts 659903706559, free_ts 658644583316
 prep_new_page mm/page_alloc.c:2552 [inline]
 get_page_from_freelist+0x3246/0x33c0 mm/page_alloc.c:4325
 __alloc_pages+0x255/0x670 mm/page_alloc.c:5591
 folio_alloc+0x1e/0x60 mm/mempolicy.c:2293
 filemap_alloc_folio+0xde/0x500 mm/filemap.c:976
 __filemap_get_folio+0x719/0xe50 mm/filemap.c:1970
 pagecache_get_page+0x2c/0x240 mm/folio-compat.c:99
 find_or_create_page include/linux/pagemap.h:632 [inline]
 grow_dev_page fs/buffer.c:989 [inline]
 grow_buffers fs/buffer.c:1054 [inline]
 __getblk_slow fs/buffer.c:1081 [inline]
 __getblk_gfp+0x215/0xa40 fs/buffer.c:1376
 __bread_gfp+0x2e/0x380 fs/buffer.c:1410
 sb_bread include/linux/buffer_head.h:341 [inline]
 read_super_block+0x91/0x800 fs/reiserfs/super.c:1604
 reiserfs_fill_super+0x912/0x2620 fs/reiserfs/super.c:1966
 mount_bdev+0x271/0x3a0 fs/super.c:1380
 legacy_get_tree+0xef/0x190 fs/fs_context.c:610
 vfs_get_tree+0x8c/0x270 fs/super.c:1510
 do_new_mount+0x28f/0xae0 fs/namespace.c:3042
 do_mount fs/namespace.c:3385 [inline]
 __do_sys_mount fs/namespace.c:3594 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3571
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1453 [inline]
 free_pcp_prepare mm/page_alloc.c:1503 [inline]
 free_unref_page_prepare+0xe2f/0xe70 mm/page_alloc.c:3387
 free_unref_page_list+0x596/0x830 mm/page_alloc.c:3528
 release_pages+0x219e/0x2470 mm/swap.c:1042
 __pagevec_release+0x84/0x100 mm/swap.c:1062
 pagevec_release include/linux/pagevec.h:63 [inline]
 folio_batch_release include/linux/pagevec.h:132 [inline]
 shmem_undo_range+0x6b6/0x1dd0 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1041 [inline]
 shmem_evict_inode+0x258/0x9f0 mm/shmem.c:1156
 evict+0x2a4/0x620 fs/inode.c:665
 __dentry_kill+0x436/0x650 fs/dcache.c:607
 dentry_kill+0xbb/0x290
 dput+0x1f3/0x420 fs/dcache.c:913
 __fput+0x5e4/0x890 fs/file_table.c:329
 task_work_run+0x24a/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:296
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86

Memory state around the buggy address:
 ffff88803b267f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88803b267f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88803b268000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88803b268080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88803b268100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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