==================================================================
BUG: KASAN: use-after-free in ext4_ext_insert_extent+0x2a72/0x4c30 fs/ext4/extents.c:2152
Read of size 324636 at addr ffff8881254f8a88 by task syz.2.16/522

CPU: 0 PID: 522 Comm: syz.2.16 Not tainted 5.10.234-syzkaller-1006652-g3f5f2283d684 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:452
 kasan_check_range+0x293/0x2a0 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 ext4_ext_insert_extent+0x2a72/0x4c30 fs/ext4/extents.c:2152
 ext4_split_extent_at+0x84a/0x1240 fs/ext4/extents.c:3229
 ext4_force_split_extent_at fs/ext4/extents.c:318 [inline]
 ext4_ext_remove_space+0x719/0x4e10 fs/ext4/extents.c:2873
 ext4_punch_hole+0x720/0xb10 fs/ext4/inode.c:4216
 ext4_fallocate+0x2e8/0x1cc0 fs/ext4/extents.c:4756
 vfs_fallocate+0x492/0x570 fs/open.c:310
 ksys_fallocate fs/open.c:333 [inline]
 __do_sys_fallocate fs/open.c:341 [inline]
 __se_sys_fallocate fs/open.c:339 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:339
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f815d563de9
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:00007f815cfb5038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f815d77d080 RCX: 00007f815d563de9
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000004
RBP: 00007f815d5e52a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001a00 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f815d77d080 R15: 00007fff5b5bfc28

The buggy address belongs to the page:
page:ffffea0004953e00 refcount:1 mapcount:1 mapping:0000000000000000 index:0x400000033 pfn:0x1254f8
anon flags: 0x4000000000080014(uptodate|lru|swapbacked)
raw: 4000000000080014 ffffea0004953d08 ffffea0004953e48 ffff88810e3e0451
raw: 0000000400000033 0000000000000000 0000000100000000 ffff88810ef3a000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff88810ef3a000
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x8100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|0x8000000), pid 518, ts 57832084301, free_ts 35385655033
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x166/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348
 __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]
 do_anonymous_page mm/memory.c:3963 [inline]
 handle_pte_fault+0x175a/0x3e10 mm/memory.c:4786
 __handle_mm_fault mm/memory.c:4944 [inline]
 handle_mm_fault+0x11d6/0x1a10 mm/memory.c:5358
 do_user_addr_fault arch/x86/mm/fault.c:1362 [inline]
 handle_page_fault arch/x86/mm/fault.c:1428 [inline]
 exc_page_fault+0x2a6/0x5b0 arch/x86/mm/fault.c:1484
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
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+0x2ae/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x122/0xb20 mm/page_alloc.c:3443
 release_pages+0xea0/0xef0 mm/swap.c:1103
 free_pages_and_swap_cache+0x8a/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+0xd0/0x180 mm/mmu_gather.c:247
 zap_pte_range mm/memory.c:1385 [inline]
 zap_pmd_range mm/memory.c:1435 [inline]
 zap_pud_range mm/memory.c:1464 [inline]
 zap_p4d_range mm/memory.c:1485 [inline]
 unmap_page_range+0x1f34/0x23b0 mm/memory.c:1506
 unmap_single_vma mm/memory.c:1551 [inline]
 unmap_vmas+0x37f/0x4f0 mm/memory.c:1583
 exit_mmap+0x2e6/0x560 mm/mmap.c:3373
 __mmput+0x95/0x2d0 kernel/fork.c:1153
 mmput+0x59/0x170 kernel/fork.c:1176
 exit_mm kernel/exit.c:539 [inline]
 do_exit+0xbda/0x2a50 kernel/exit.c:850
 do_group_exit+0x141/0x310 kernel/exit.c:985
 get_signal+0x10a0/0x1410 kernel/signal.c:2793
 arch_do_signal_or_restart+0xbd/0x17c0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0x9b/0xd0 kernel/entry/common.c:169
 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline]
 syscall_exit_to_user_mode+0xa2/0x1a0 kernel/entry/common.c:274

Memory state around the buggy address:
 ffff888125529f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888125529f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812552a000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88812552a080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812552a100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop2): ext4_free_blocks:5685: comm syz.2.16: Freeing blocks not in datazone - block = 72728140209669, count = 1
EXT4-fs (loop2): Remounting filesystem read-only
EXT4-fs error (device loop2) in ext4_reserve_inode_write:5900: Corrupt filesystem
EXT4-fs error (device loop2): ext4_punch_hole:4229: inode #16: comm syz.2.16: mark_inode_dirty error