EXT4-fs error (device loop3): ext4_mb_mark_diskspace_used:3342: comm syz.3.2851: Allocating blocks 497-513 which overlap fs metadata
EXT4-fs (loop3): pa ffff88812e1e0f18: logic 128, phys. 385, len 8
EXT4-fs error (device loop3): ext4_mb_release_inode_pa:4359: group 0, free 0, pa_free 1
==================================================================
BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2596 [inline]
BUG: KASAN: use-after-free in ext4_ext_remove_space+0x3a6a/0x4920 fs/ext4/extents.c:2934
Read of size 4 at addr ffff8881438a5c18 by task syz.3.2851/11707

CPU: 0 PID: 11707 Comm: syz.3.2851 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_rm_leaf fs/ext4/extents.c:2596 [inline]
 ext4_ext_remove_space+0x3a6a/0x4920 fs/ext4/extents.c:2934
 ext4_ext_truncate+0x169/0x1f0 fs/ext4/extents.c:4467
 ext4_truncate+0xaea/0x1290 fs/ext4/inode.c:4373
 ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
 ext4_write_begin+0xd78/0x15a0 fs/ext4/inode.c:1276
 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_pwrite64 fs/read_write.c:712 [inline]
 __do_sys_pwrite64 fs/read_write.c:722 [inline]
 __se_sys_pwrite64 fs/read_write.c:719 [inline]
 __x64_sys_pwrite64+0x191/0x220 fs/read_write.c:719
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fcffe25b749
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:00007fcffccc3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fcffe4b1fa0 RCX: 00007fcffe25b749
RDX: 00000000200000c1 RSI: 00002000000000c0 RDI: 0000000000000009
RBP: 00007fcffe2dff91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000009000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcffe4b2038 R14: 00007fcffe4b1fa0 R15: 00007fffa59dc758

The buggy address belongs to the page:
page:ffffea00050e2940 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1438a5
flags: 0x4000000000000000()
raw: 4000000000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 9, migratetype Movable, gfp_mask 0x1c24ca(GFP_TRANSHUGE), pid 30, ts 397855044230, free_ts 397855117159
 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:5370
 __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]
 alloc_khugepaged_hugepage mm/khugepaged.c:907 [inline]
 khugepaged_alloc_hugepage mm/khugepaged.c:919 [inline]
 khugepaged_prealloc_page mm/khugepaged.c:949 [inline]
 khugepaged_do_scan mm/khugepaged.c:2287 [inline]
 khugepaged+0x2fe/0xeb0 mm/khugepaged.c:2345
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
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_pages_ok+0x7fc/0x820 mm/page_alloc.c:1629
 free_compound_page+0x73/0x90 mm/page_alloc.c:710
 free_transhuge_page+0x20c/0x230 mm/huge_memory.c:2783
 destroy_compound_page include/linux/mm.h:970 [inline]
 __put_compound_page+0x77/0xb0 mm/swap.c:117
 __put_page+0xbd/0xe0 mm/swap.c:133
 put_page include/linux/mm.h:1268 [inline]
 khugepaged_do_scan mm/khugepaged.c:2308 [inline]
 khugepaged+0x838/0xeb0 mm/khugepaged.c:2345
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Memory state around the buggy address:
 ffff8881438a5b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881438a5b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881438a5c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff8881438a5c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881438a5d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
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