==================================================================
BUG: KASAN: use-after-free in ext4_ext_insert_extent+0x2841/0x4530 fs/ext4/extents.c:2153
Read of size 369228 at addr ffff888130fd4c3c by task syz.4.20/522

CPU: 0 PID: 522 Comm: syz.4.20 Not tainted 5.10.240-syzkaller-1008085-g1154f779f3f3 #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
 ext4_ext_insert_extent+0x2841/0x4530 fs/ext4/extents.c:2153
 ext4_ext_map_blocks+0x148f/0x5d40 fs/ext4/extents.c:4356
 ext4_map_blocks+0x978/0x1bc0 fs/ext4/inode.c:674
 _ext4_get_block+0x1bb/0x4b0 fs/ext4/inode.c:817
 ext4_get_block+0x39/0x50 fs/ext4/inode.c:834
 ext4_block_write_begin+0x567/0x1330 fs/ext4/inode.c:1101
 ext4_write_begin+0x651/0x1550 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x455/0xe80 fs/ext4/inode.c:3033
 generic_perform_write+0x2be/0x510 mm/filemap.c:3509
 ext4_buffered_write_iter+0x4b8/0x640 fs/ext4/file.c:271
 ext4_file_write_iter+0x536/0x1980 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2066 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x725/0xd60 fs/read_write.c:605
 ksys_write+0x140/0x240 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:667
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f352bf72169
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:00007f352b9c3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f352c18b080 RCX: 00007f352bf72169
RDX: 00000000002a979d RSI: 0000400000000000 RDI: 0000000000000004
RBP: 00007f352bff32a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f352c18b080 R15: 00007ffefe3f4c38

The buggy address belongs to the page:
page:ffffea0004c3f500 refcount:2 mapcount:0 mapping:ffff888110308b10 index:0x3f pfn:0x130fd4
aops:def_blk_aops ino:0
flags: 0x4000000000002014(uptodate|lru|private)
raw: 4000000000002014 ffff88810a94b020 ffffea00048b9348 ffff888110308b10
raw: 000000000000003f ffff888125bdd690 00000002ffffffff ffff88810aa70000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff88810aa70000
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 522, ts 54130721053, free_ts 0
 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_gfp include/linux/buffer_head.h:368 [inline]
 ext4_ext_grow_indepth fs/ext4/extents.c:1327 [inline]
 ext4_ext_create_new_leaf fs/ext4/extents.c:1426 [inline]
 ext4_ext_insert_extent+0x1084/0x4530 fs/ext4/extents.c:2098
 ext4_ext_map_blocks+0x148f/0x5d40 fs/ext4/extents.c:4356
 ext4_map_blocks+0x978/0x1bc0 fs/ext4/inode.c:674
 _ext4_get_block+0x1bb/0x4b0 fs/ext4/inode.c:817
 ext4_get_block+0x39/0x50 fs/ext4/inode.c:834
 ext4_block_write_begin+0x567/0x1330 fs/ext4/inode.c:1101
 ext4_write_begin+0x651/0x1550 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x455/0xe80 fs/ext4/inode.c:3033
 generic_perform_write+0x2be/0x510 mm/filemap.c:3509
 ext4_buffered_write_iter+0x4b8/0x640 fs/ext4/file.c:271
 ext4_file_write_iter+0x536/0x1980 fs/ext4/file.c:-1
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888131008f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888131008f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888131009000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888131009080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888131009100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================