EXT4-fs (loop2): failed to convert unwritten extents to written extents -- potential data loss!  (inode 19, error -117)
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945
Read of size 4 at addr ffff888123539a58 by task kworker/u4:1/9

CPU: 0 PID: 9 Comm: kworker/u4:1 Not tainted 5.10.237-syzkaller-1007474-gcf6ed0f1511d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
 ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945
 ext4_ext_map_blocks+0x1de/0x5d40 fs/ext4/extents.c:4159
 ext4_map_blocks+0x978/0x1bc0 fs/ext4/inode.c:674
 ext4_convert_unwritten_extents+0x21c/0x3f0 fs/ext4/extents.c:4860
 ext4_convert_unwritten_io_end_vec+0x103/0x180 fs/ext4/extents.c:4899
 ext4_end_io_end fs/ext4/page-io.c:189 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:262 [inline]
 ext4_end_io_rsv_work+0x2b9/0x600 fs/ext4/page-io.c:276
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

The buggy address belongs to the page:
page:ffffea00048d4e40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x123539
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea00048d4e88 ffffea00048d4e08 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff888123539900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888123539980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888123539a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                    ^
 ffff888123539a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888123539b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop2): ext4_map_blocks:740: inode #19: block 29: comm kworker/u4:1: lblock 29 mapped to illegal pblock 29 (length 1)
EXT4-fs warning (device loop2): ext4_convert_unwritten_extents:4867: inode #19: block 29: len 1: ext4_ext_map_blocks returned -117
EXT4-fs error (device loop2): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop2) in ext4_reserve_inode_write:5932: Corrupt filesystem
EXT4-fs error (device loop2): ext4_convert_unwritten_extents:4868: inode #19: comm kworker/u4:1: mark_inode_dirty error
EXT4-fs (loop2): failed to convert unwritten extents to written extents -- potential data loss!  (inode 19, error -117)
EXT4-fs error (device loop2): ext4_map_blocks:740: inode #19: block 30: comm kworker/u4:1: lblock 30 mapped to illegal pblock 30 (length 1)
EXT4-fs warning (device loop2): ext4_convert_unwritten_extents:4867: inode #19: block 30: len 1: ext4_ext_map_blocks returned -117
EXT4-fs (loop2): failed to convert unwritten extents to written extents -- potential data loss!  (inode 19, error -117)
EXT4-fs error (device loop4): ext4_map_blocks:740: inode #19: block 248: comm kworker/u4:1: lblock 40 mapped to illegal pblock 248 (length 1)
EXT4-fs warning (device loop4): ext4_convert_unwritten_extents:4867: inode #19: block 40: len 1: ext4_ext_map_blocks returned -117
EXT4-fs error (device loop4): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop4) in ext4_reserve_inode_write:5932: Corrupt filesystem
EXT4-fs error (device loop4): ext4_convert_unwritten_extents:4868: inode #19: comm kworker/u4:1: mark_inode_dirty error
EXT4-fs (loop4): failed to convert unwritten extents to written extents -- potential data loss!  (inode 19, error -117)
EXT4-fs error (device loop3): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop3): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop1): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop1): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop0): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop5): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop4): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop1): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop0): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop5): __ext4_get_inode_loc:4438: comm kworker/u4:1: Invalid inode table block 34360905424 in block_group 0