REISERFS (device loop3): Using tea hash to sort names
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BUG: KASAN: use-after-free in strlen+0x58/0x70 lib/string.c:418
Read of size 1 at addr ffff88804beccfa3 by task syz-executor.3/12203

CPU: 1 PID: 12203 Comm: syz-executor.3 Not tainted 6.6.0-syzkaller-03860-g5a6a09e97199 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
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+0x175/0x1b0 mm/kasan/report.c:588
 strlen+0x58/0x70 lib/string.c:418
 set_de_name_and_namelen fs/reiserfs/namei.c:82 [inline]
 linear_search_in_dir_item fs/reiserfs/namei.c:262 [inline]
 reiserfs_find_entry+0x982/0x19b0 fs/reiserfs/namei.c:331
 reiserfs_lookup+0x1e2/0x580 fs/reiserfs/namei.c:368
 __lookup_slow+0x282/0x3e0 fs/namei.c:1694
 lookup_one_len+0x18b/0x2d0 fs/namei.c:2746
 reiserfs_lookup_privroot+0x89/0x180 fs/reiserfs/xattr.c:977
 reiserfs_fill_super+0x21c1/0x2620 fs/reiserfs/super.c:2174
 mount_bdev+0x237/0x300 fs/super.c:1647
 legacy_get_tree+0xef/0x190 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1768
 do_new_mount+0x28f/0xae0 fs/namespace.c:3337
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f7b04e7e1ea
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:00007f7b05bfcee8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f7b05bfcf80 RCX: 00007f7b04e7e1ea
RDX: 00000000200000c0 RSI: 0000000020000040 RDI: 00007f7b05bfcf40
RBP: 00000000200000c0 R08: 00007f7b05bfcf80 R09: 000000000000800c
R10: 000000000000800c R11: 0000000000000202 R12: 0000000020000040
R13: 00007f7b05bfcf40 R14: 000000000000111d R15: 0000000020000300
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00012fb300 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x4becc
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 11925, tgid 11924 (syz-executor.0), ts 564887022971, free_ts 565747995478
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0x31db/0x3360 mm/page_alloc.c:3170
 __alloc_pages+0x255/0x670 mm/page_alloc.c:4426
 __folio_alloc+0x13/0x30 mm/page_alloc.c:4458
 vma_alloc_folio+0x48a/0x9a0 mm/mempolicy.c:2264
 shmem_alloc_folio mm/shmem.c:1658 [inline]
 shmem_alloc_and_acct_folio+0x438/0x9b0 mm/shmem.c:1683
 shmem_get_folio_gfp+0xca4/0x2b60 mm/shmem.c:2020
 shmem_get_folio mm/shmem.c:2143 [inline]
 shmem_write_begin+0x170/0x300 mm/shmem.c:2688
 generic_perform_write+0x31b/0x630 mm/filemap.c:3969
 shmem_file_write_iter+0xfc/0x120 mm/shmem.c:2865
 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+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x8c3/0x9f0 mm/page_alloc.c:2312
 free_unref_page_list+0x596/0x830 mm/page_alloc.c:2451
 release_pages+0x2113/0x23f0 mm/swap.c:1042
 __folio_batch_release+0x84/0x100 mm/swap.c:1062
 folio_batch_release include/linux/pagevec.h:83 [inline]
 shmem_undo_range+0x6ad/0x19c0 mm/shmem.c:1022
 shmem_truncate_range mm/shmem.c:1114 [inline]
 shmem_evict_inode+0x29b/0xa60 mm/shmem.c:1243
 evict+0x2a4/0x620 fs/inode.c:664
 __dentry_kill+0x436/0x650 fs/dcache.c:607
 dentry_kill+0xbb/0x290
 dput+0x21e/0x470 fs/dcache.c:913
 __fput+0x60b/0xa10 fs/file_table.c:402
 task_work_run+0x24a/0x300 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
 __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+0x50/0x110 arch/x86/entry/common.c:88

Memory state around the buggy address:
 ffff88804becce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804beccf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804beccf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff88804becd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804becd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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