EXT4-fs (loop0): encrypted files will use data=ordered instead of data journaling mode
EXT4-fs (loop0): 1 truncate cleaned up
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none.
==================================================================
BUG: KASAN: use-after-free in ext4_search_dir+0xf8/0x1c0 fs/ext4/namei.c:1544
Read of size 1 at addr ffff888121bb3c86 by task syz-executor955/315

CPU: 0 PID: 315 Comm: syz-executor955 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348
 ext4_search_dir+0xf8/0x1c0 fs/ext4/namei.c:1544
 ext4_find_inline_entry+0x4f2/0x630 fs/ext4/inline.c:1756
 __ext4_find_entry+0x307/0x1a10 fs/ext4/namei.c:1617
 ext4_lookup_entry fs/ext4/namei.c:1774 [inline]
 ext4_lookup+0x181/0x710 fs/ext4/namei.c:1842
 lookup_one_qstr_excl+0x125/0x270 fs/namei.c:1612
 filename_create+0x23d/0x440 fs/namei.c:3884
 do_mkdirat+0x5c/0x4d0 fs/namei.c:4128
 __do_sys_mkdir fs/namei.c:4158 [inline]
 __se_sys_mkdir fs/namei.c:4156 [inline]
 __x64_sys_mkdir+0x6e/0x80 fs/namei.c:4156
 x64_sys_call+0x966/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:84
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f71ae45b427
Code: 1f 40 00 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 cb ba 01 00 66 2e 0f 1f 84 00 00 00 00 00 90 b8 53 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 d8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fff404cfef8 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f71ae45b427
RDX: 000000000399446c RSI: 00000000000001ff RDI: 0000200000000080
RBP: 0000200000000140 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000080
R13: 00007fff404cff90 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000486ecc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x121bb3
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x500cc2(GFP_HIGHUSER|__GFP_ACCOUNT), pid 273, tgid 273 (sshd-session), ts 24192229247, free_ts 24192845056
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4586
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
 __alloc_pages_node include/linux/gfp.h:236 [inline]
 alloc_pages_node include/linux/gfp.h:259 [inline]
 alloc_pages include/linux/gfp.h:270 [inline]
 pipe_write+0x588/0x1960 fs/pipe.c:501
 call_write_iter include/linux/fs.h:2282 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ef/0xd00 fs/read_write.c:584
 ksys_write+0x14a/0x260 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1580 [inline]
 free_pcp_prepare mm/page_alloc.c:1654 [inline]
 free_unref_page_prepare+0x80c/0x820 mm/page_alloc.c:3621
 free_unref_page+0x93/0x530 mm/page_alloc.c:3719
 __folio_put_small mm/swap.c:100 [inline]
 __folio_put+0xac/0xe0 mm/swap.c:123
 folio_put include/linux/mm.h:1442 [inline]
 put_page include/linux/mm.h:1494 [inline]
 anon_pipe_buf_release+0x15f/0x1d0 fs/pipe.c:138
 pipe_buf_release include/linux/pipe_fs_i.h:199 [inline]
 pipe_read+0x582/0x1070 fs/pipe.c:324
 call_read_iter include/linux/fs.h:2276 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x46e/0x930 fs/read_write.c:470
 ksys_read+0x14a/0x260 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:621
 x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888121bb3b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888121bb3c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888121bb3c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888121bb3d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888121bb3d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0): ext4_check_all_de:666: inode #12: block 7: comm syz-executor955: bad entry in directory: directory entry overrun - offset=0, inode=901261600, rec_len=7976, size=124 fake=0