EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:4113: comm syz.0.0: Allocating blocks 497-513 which overlap fs metadata
EXT4-fs (loop0): pa ffff888012032828: logic 128, phys. 385, len 8
EXT4-fs error (device loop0): ext4_mb_release_inode_pa:5364: group 0, free 0, pa_free 1
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BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2627 [inline]
BUG: KASAN: use-after-free in ext4_ext_remove_space+0x3211/0x42f0 fs/ext4/extents.c:2965
Read of size 4 at addr ffff8880556d3c18 by task syz.0.0/5344

CPU: 0 UID: 0 PID: 5344 Comm: syz.0.0 Not tainted 6.16.0-rc4-syzkaller-00348-g772b78c2abd8 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 ext4_ext_rm_leaf fs/ext4/extents.c:2627 [inline]
 ext4_ext_remove_space+0x3211/0x42f0 fs/ext4/extents.c:2965
 ext4_ext_truncate+0x17e/0x300 fs/ext4/extents.c:4484
 ext4_truncate+0x9bb/0x1100 fs/ext4/inode.c:4574
 ext4_truncate_failed_write fs/ext4/truncate.h:22 [inline]
 ext4_write_begin+0xf59/0x1680 fs/ext4/inode.c:1366
 ext4_da_write_begin+0x449/0xd20 fs/ext4/inode.c:3057
 generic_perform_write+0x2c7/0x910 mm/filemap.c:4112
 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299
 ext4_file_write_iter+0x298/0x1bc0 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x548/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f05ad98e929
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:00007f05ae82b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f05adbb6080 RCX: 00007f05ad98e929
RDX: 000000000208e24b RSI: 0000200000000280 RDI: 0000000000000009
RBP: 00007f05ada10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f05adbb6080 R15: 00007ffc864ef958
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x556d3
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000000 ffffea000155b508 ffffea000155b488 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:
 ffff8880556d3b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880556d3b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880556d3c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff8880556d3c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880556d3d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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