==================================================================
BUG: KASAN: use-after-free in dx_insert_block+0xe8/0x260 fs/ext4/namei.c:1387
Read of size 157024 at addr ffff888127f9b028 by task syz.8.90/761

CPU: 1 PID: 761 Comm: syz.8.90 Not tainted 6.1.128-syzkaller-1167812-g33c9d4844afc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x158/0x4e0 mm/kasan/report.c:427
 kasan_report+0x13c/0x170 mm/kasan/report.c:531
 kasan_check_range+0x294/0x2a0 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 dx_insert_block+0xe8/0x260 fs/ext4/namei.c:1387
 do_split+0x1e0e/0x2250 fs/ext4/namei.c:2080
 make_indexed_dir+0xeaf/0x1590 fs/ext4/namei.c:2392
 ext4_add_entry+0xbbf/0xed0 fs/ext4/namei.c:2504
 __ext4_link+0x4e9/0x790 fs/ext4/namei.c:3522
 ext4_link+0x1f3/0x290 fs/ext4/namei.c:3563
 vfs_link+0x645/0x7f0 fs/namei.c:4598
 do_linkat+0x34d/0x9f0 fs/namei.c:4669
 __do_sys_link fs/namei.c:4703 [inline]
 __se_sys_link fs/namei.c:4701 [inline]
 __x64_sys_link+0x86/0x90 fs/namei.c:4701
 x64_sys_call+0x282/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:87
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4d4678d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4d4752f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 00007f4d469a5fa0 RCX: 00007f4d4678d169
RDX: 0000000000000000 RSI: 0000400000000bc0 RDI: 0000400000001240
RBP: 00007f4d4680e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4d469a5fa0 R15: 00007fff11816b78
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00049fe6c0 refcount:3 mapcount:1 mapping:ffff88810054fdd0 index:0x1 pfn:0x127f9b
memcg:ffff888100336000
aops:def_blk_aops ino:700008
flags: 0x460000000032205e(referenced|uptodate|dirty|lru|workingset|private|mappedtodisk|unevictable|mlocked|zone=1)
raw: 460000000032205e dead000000000100 dead000000000001 ffff88810054fdd0
raw: 0000000000000001 ffff88810bf61d20 0000000300000000 ffff888100336000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x152c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 528, tgid 528 (udevd), ts 79080223540, free_ts 54359762496
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x213/0x220 mm/page_alloc.c:2637
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2644
 get_page_from_freelist+0x3a98/0x3b10 mm/page_alloc.c:4539
 __alloc_pages+0x234/0x610 mm/page_alloc.c:5837
 __folio_alloc+0x15/0x40 mm/page_alloc.c:5869
 __folio_alloc_node include/linux/gfp.h:245 [inline]
 folio_alloc include/linux/gfp.h:274 [inline]
 filemap_alloc_folio include/linux/pagemap.h:513 [inline]
 page_cache_ra_unbounded+0x2cb/0x800 mm/readahead.c:260
 do_page_cache_ra mm/readahead.c:312 [inline]
 force_page_cache_ra mm/readahead.c:343 [inline]
 page_cache_sync_ra+0x394/0x450 mm/readahead.c:727
 page_cache_sync_readahead include/linux/pagemap.h:1257 [inline]
 filemap_get_pages mm/filemap.c:2688 [inline]
 filemap_read+0x7fa/0x2600 mm/filemap.c:2783
 blkdev_read_iter+0x3de/0x530 block/fops.c:613
 call_read_iter include/linux/fs.h:2268 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x801/0xae0 fs/read_write.c:470
 ksys_read+0x199/0x2c0 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+0x28/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 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:1545 [inline]
 free_pcp_prepare mm/page_alloc.c:1619 [inline]
 free_unref_page_prepare+0x9f1/0xa00 mm/page_alloc.c:3581
 free_unref_page+0xb2/0x5c0 mm/page_alloc.c:3677
 free_the_page mm/page_alloc.c:830 [inline]
 __free_pages+0x61/0xf0 mm/page_alloc.c:5926
 __vunmap+0x9c6/0xb80 mm/vmalloc.c:2729
 __vfree mm/vmalloc.c:2778 [inline]
 vfree+0x5c/0x80 mm/vmalloc.c:2809
 kcov_put kernel/kcov.c:437 [inline]
 kcov_close+0x2b/0x50 kernel/kcov.c:533
 __fput+0x1e5/0x870 fs/file_table.c:320
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x24d/0x2e0 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0xbd0/0x2b80 kernel/exit.c:877
 do_group_exit+0x21a/0x2d0 kernel/exit.c:1027
 get_signal+0x169d/0x1820 kernel/signal.c:2889
 arch_do_signal_or_restart+0xb0/0x16f0 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x74/0xa0 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x26/0x130 kernel/entry/common.c:303

Memory state around the buggy address:
 ffff888127faef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888127faef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888127faf000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888127faf080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888127faf100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs error (device loop8): ext4_dx_csum_set:531: inode #2: comm syz.8.90: dir seems corrupt?  Run e2fsck -D.