==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbab/0xdb0 fs/ext4/extents.c:945
Read of size 4 at addr ffff888124c10a58 by task kworker/u4:4/428

CPU: 1 PID: 428 Comm: kworker/u4:4 Not tainted 5.10.209-syzkaller-999850-ge7daca75b4c3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
 ext4_find_extent+0xbab/0xdb0 fs/ext4/extents.c:945
 ext4_ext_map_blocks+0x26d/0x6be0 fs/ext4/extents.c:4097
 ext4_map_blocks+0xaa7/0x1ec0 fs/ext4/inode.c:646
 ext4_convert_unwritten_extents+0x2a3/0x5a0 fs/ext4/extents.c:4808
 ext4_convert_unwritten_io_end_vec+0x104/0x180 fs/ext4/extents.c:4847
 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+0x358/0x690 fs/ext4/page-io.c:276
 process_one_work+0x6dc/0xbd0 kernel/workqueue.c:2301
 worker_thread+0xaea/0x1510 kernel/workqueue.c:2447
 kthread+0x34b/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:299

The buggy address belongs to the page:
page:ffffea0004930400 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x124c10
flags: 0x4000000000000000()
raw: 4000000000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff888124c10900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888124c10980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888124c10a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                    ^
 ffff888124c10a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888124c10b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop1): ext4_map_blocks:716: inode #19: block 7: comm kworker/u4:4: lblock 7 mapped to illegal pblock 7 (length 1)
EXT4-fs warning (device loop1): ext4_convert_unwritten_extents:4815: inode #19: block 7: len 1: ext4_ext_map_blocks returned -117
EXT4-fs error (device loop1): __ext4_get_inode_loc:4426: comm kworker/u4:4: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop1) in ext4_reserve_inode_write:5886: Corrupt filesystem
EXT4-fs error (device loop1): ext4_convert_unwritten_extents:4816: inode #19: comm kworker/u4:4: mark_inode_dirty error
EXT4-fs (loop1): failed to convert unwritten extents to written extents -- potential data loss!  (inode 19, error -117)
EXT4-fs error (device loop0): __ext4_get_inode_loc:4426: comm kworker/u4:4: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop0): __ext4_get_inode_loc:4426: comm kworker/u4:4: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop3): __ext4_get_inode_loc:4426: comm kworker/u4:4: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop4): ext4_map_blocks:716: inode #19: block 228: comm kworker/u4:4: lblock 20 mapped to illegal pblock 228 (length 1)
EXT4-fs warning (device loop4): ext4_convert_unwritten_extents:4815: inode #19: block 20: len 1: ext4_ext_map_blocks returned -117
EXT4-fs error (device loop4): __ext4_get_inode_loc:4426: comm kworker/u4:4: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop4) in ext4_reserve_inode_write:5886: Corrupt filesystem
EXT4-fs error (device loop4): ext4_convert_unwritten_extents:4816: inode #19: comm kworker/u4:4: 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 loop2): __ext4_get_inode_loc:4426: comm kworker/u4:4: Invalid inode table block 34360905424 in block_group 0
EXT4-fs error (device loop2): __ext4_get_inode_loc:4426: comm kworker/u4:4: Invalid inode table block 34360905424 in block_group 0