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BUG: KASAN: use-after-free in bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
BUG: KASAN: use-after-free in search_by_entry_key+0x80b/0x940 fs/reiserfs/namei.c:165
Read of size 4 at addr ffff888039e84f94 by task syz-executor.2/32400

CPU: 3 PID: 32400 Comm: syz-executor.2 Not tainted 6.7.0-rc5-syzkaller-00214-gc8e97fc6b4c0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:475
 kasan_report+0xda/0x110 mm/kasan/report.c:588
 bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
 search_by_entry_key+0x80b/0x940 fs/reiserfs/namei.c:165
 reiserfs_find_entry+0x1dc/0xe70 fs/reiserfs/namei.c:322
 reiserfs_lookup+0x1f5/0x690 fs/reiserfs/namei.c:368
 __lookup_slow+0x24d/0x450 fs/namei.c:1694
 lookup_one_len+0x17d/0x1b0 fs/namei.c:2746
 reiserfs_lookup_privroot+0x94/0x200 fs/reiserfs/xattr.c:977
 reiserfs_fill_super+0x20f9/0x3160 fs/reiserfs/super.c:2174
 mount_bdev+0x1f3/0x2e0 fs/super.c:1650
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x370 fs/super.c:1771
 do_new_mount fs/namespace.c:3337 [inline]
 path_mount+0x1492/0x1ed0 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount fs/namespace.c:3863 [inline]
 __x64_sys_mount+0x293/0x310 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7ff40ee7e2aa
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:00007ff40fbcbee8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ff40fbcbf80 RCX: 00007ff40ee7e2aa
RDX: 0000000020000080 RSI: 0000000020000040 RDI: 00007ff40fbcbf40
RBP: 0000000020000080 R08: 00007ff40fbcbf80 R09: 000000000201800c
R10: 000000000201800c R11: 0000000000000202 R12: 0000000020000040
R13: 00007ff40fbcbf40 R14: 0000000000001119 R15: 0000000020000300
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0000e7a100 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x39e84
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffff7f(buddy)
raw: 00fff00000000000 ffffea0000e73508 ffffea0000cc4908 0000000000000000
raw: 0000000000000001 0000000000000002 00000000ffffff7f 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 0x100cca(GFP_HIGHUSER_MOVABLE), pid 32364, tgid 32363 (syz-executor.0), ts 657891747953, free_ts 658019621416
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1544 [inline]
 get_page_from_freelist+0xa25/0x36d0 mm/page_alloc.c:3312
 __alloc_pages+0x22e/0x2420 mm/page_alloc.c:4568
 alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133
 shmem_alloc_folio+0x10d/0x140 mm/shmem.c:1630
 shmem_alloc_and_add_folio+0x147/0x7b0 mm/shmem.c:1670
 shmem_get_folio_gfp+0x623/0x1360 mm/shmem.c:2054
 shmem_get_folio mm/shmem.c:2136 [inline]
 shmem_write_begin+0x15a/0x360 mm/shmem.c:2719
 generic_perform_write+0x278/0x600 mm/filemap.c:3918
 shmem_file_write_iter+0x110/0x140 mm/shmem.c:2895
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x64f/0xdf0 fs/read_write.c:584
 ksys_write+0x12f/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
 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:1137 [inline]
 free_unref_page_prepare+0x4fa/0xaa0 mm/page_alloc.c:2347
 free_unref_page_list+0xe6/0xb40 mm/page_alloc.c:2533
 release_pages+0x32a/0x14f0 mm/swap.c:1042
 __folio_batch_release+0x77/0xe0 mm/swap.c:1062
 folio_batch_release include/linux/pagevec.h:83 [inline]
 shmem_undo_range+0x57a/0x1140 mm/shmem.c:1004
 shmem_truncate_range mm/shmem.c:1113 [inline]
 shmem_evict_inode+0x39f/0xba0 mm/shmem.c:1241
 evict+0x2ed/0x6b0 fs/inode.c:666
 iput_final fs/inode.c:1777 [inline]
 iput.part.0+0x560/0x7b0 fs/inode.c:1803
 iput+0x5c/0x80 fs/inode.c:1793
 dentry_unlink_inode+0x292/0x430 fs/dcache.c:401
 __dentry_kill+0x3b8/0x640 fs/dcache.c:607
 dentry_kill fs/dcache.c:733 [inline]
 dput+0x7eb/0xd90 fs/dcache.c:913
 __fput+0x3b9/0xb70 fs/file_table.c:402
 task_work_run+0x14d/0x240 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x217/0x240 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x1e/0x60 kernel/entry/common.c:296

Memory state around the buggy address:
 ffff888039e84e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888039e84f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888039e84f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff888039e85000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888039e85080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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