==================================================================
BUG: KASAN: use-after-free in dx_insert_block fs/ext4/namei.c:1358 [inline]
BUG: KASAN: use-after-free in do_split+0x1995/0x1e30 fs/ext4/namei.c:2044
Read of size 157024 at addr ffff888123d26028 by task syz.3.96/787

CPU: 1 PID: 787 Comm: syz.3.96 Not tainted 5.10.239-syzkaller-1007860-g6de38b5f6c2b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 dx_insert_block fs/ext4/namei.c:1358 [inline]
 do_split+0x1995/0x1e30 fs/ext4/namei.c:2044
 make_indexed_dir+0xd58/0x13f0 fs/ext4/namei.c:2348
 ext4_add_entry+0xc05/0xf10 fs/ext4/namei.c:2460
 __ext4_link+0x4db/0x760 fs/ext4/namei.c:3647
 ext4_link+0x1de/0x270 fs/ext4/namei.c:3688
 vfs_link+0x684/0x880 fs/namei.c:4213
 do_linkat+0x381/0x660 fs/namei.c:4281
 __do_sys_link fs/namei.c:4310 [inline]
 __se_sys_link fs/namei.c:4308 [inline]
 __x64_sys_link+0x68/0x80 fs/namei.c:4308
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f335e742809
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:00007f335e1c1058 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 00007f335e907fa0 RCX: 00007f335e742809
RDX: 0000000000000000 RSI: 0000000020000bc0 RDI: 0000000020001240
RBP: 00007f335e7b593e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f335e907fa0 R15: 00007ffc5f8d8dd8

The buggy address belongs to the page:
page:ffffea00048f4980 refcount:3 mapcount:1 mapping:ffff88810feb97d0 index:0x1 pfn:0x123d26
aops:def_blk_aops ino:0
flags: 0x400000000032201e(referenced|uptodate|dirty|lru|private|mappedtodisk|unevictable|mlocked)
raw: 400000000032201e ffffea0004989dc8 ffffea0004a93808 ffff88810feb97d0
raw: 0000000000000001 ffff88811a653540 0000000300000000 ffff888128f92000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff888128f92000
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 787, ts 72060066176, free_ts 69582873758
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357
 __alloc_pages include/linux/gfp.h:544 [inline]
 __alloc_pages_node include/linux/gfp.h:557 [inline]
 alloc_pages_node include/linux/gfp.h:571 [inline]
 alloc_pages include/linux/gfp.h:590 [inline]
 __page_cache_alloc include/linux/pagemap.h:290 [inline]
 pagecache_get_page+0x642/0x930 mm/filemap.c:1848
 find_or_create_page include/linux/pagemap.h:402 [inline]
 grow_dev_page fs/buffer.c:976 [inline]
 grow_buffers fs/buffer.c:1045 [inline]
 __getblk_slow fs/buffer.c:1072 [inline]
 __getblk_gfp+0x212/0x780 fs/buffer.c:1370
 sb_getblk include/linux/buffer_head.h:361 [inline]
 ext4_getblk fs/ext4/inode.c:878 [inline]
 ext4_bread_batch+0x1cc/0x720 fs/ext4/inode.c:944
 __ext4_find_entry+0xedc/0x1970 fs/ext4/namei.c:1643
 ext4_lookup_entry fs/ext4/namei.c:1746 [inline]
 ext4_lookup+0x292/0x840 fs/ext4/namei.c:1814
 lookup_open fs/namei.c:3226 [inline]
 open_last_lookups fs/namei.c:3317 [inline]
 path_openat+0x1127/0x3160 fs/namei.c:3506
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3536
 do_sys_openat2+0x14c/0x6d0 fs/open.c:1217
 do_sys_open fs/open.c:1233 [inline]
 __do_sys_creat fs/open.c:1309 [inline]
 __se_sys_creat fs/open.c:1303 [inline]
 __x64_sys_creat+0x8e/0xb0 fs/open.c:1303
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x12e/0x9b0 mm/page_alloc.c:3443
 release_pages+0xe38/0xe80 mm/swap.c:1103
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:356
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x175/0x300 mm/mmu_gather.c:326
 exit_mmap+0x2fc/0x540 mm/mmap.c:3383
 __mmput+0x93/0x2f0 kernel/fork.c:1153
 mmput+0x4e/0x150 kernel/fork.c:1176
 exit_mm kernel/exit.c:539 [inline]
 do_exit+0x9ae/0x2480 kernel/exit.c:859
 do_group_exit+0x141/0x310 kernel/exit.c:986
 get_signal+0xf7d/0x12e0 kernel/signal.c:2793
 arch_do_signal_or_restart+0xbf/0x10f0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169
 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline]
 syscall_exit_to_user_mode+0x68/0x90 kernel/entry/common.c:274
 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
 ffff888123d30f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888123d30f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888123d31000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888123d31080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888123d31100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop3): ext4_dx_csum_set:529: inode #2: comm syz.3.96: dir seems corrupt?  Run e2fsck -D.