EXT4-fs error (device loop4): ext4_mb_mark_diskspace_used:3887: comm syz.4.17: Allocating blocks 497-513 which overlap fs metadata EXT4-fs (loop4): pa ffff888111d58150: logic 128, phys. 385, len 8 EXT4-fs error (device loop4): ext4_mb_release_inode_pa:4904: group 0, free 0, pa_free 1 ------------[ cut here ]------------ kernel BUG at fs/ext4/extents.c:3186! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 371 Comm: syz.4.17 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:ext4_split_extent_at+0xe22/0xe40 fs/ext4/extents.c:3186 Code: ff ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c fc fb ff ff 4c 89 f7 49 89 d7 e8 bb e4 d2 ff 4c 89 fa e9 e9 fb ff ff e8 7e b6 93 ff <0f> 0b e8 77 b6 93 ff 0f 0b e8 70 b6 93 ff 0f 0b e8 69 b6 93 ff 0f RSP: 0018:ffffc90000ba6d00 EFLAGS: 00010283 RAX: ffffffff81d61682 RBX: 000000000000000e RCX: 0000000000080000 RDX: ffffc90002760000 RSI: 0000000000044fc6 RDI: 0000000000044fc7 RBP: ffffc90000ba6e78 R08: 0000000000000010 R09: 000000000000043b R10: dffffc0000000000 R11: ffffed10257342ea R12: dffffc0000000000 R13: 0000000000000072 R14: 0000000000000030 R15: 0000000000000010 FS: 00007f64014796c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000034000 CR3: 000000012ba5d000 CR4: 00000000003526a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ext4_split_extent+0x363/0x4c0 fs/ext4/extents.c:3385 ext4_split_convert_extents fs/ext4/extents.c:3715 [inline] ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3876 [inline] ext4_ext_map_blocks+0x10e5/0x61e0 fs/ext4/extents.c:4231 ext4_map_blocks+0x988/0x1b30 fs/ext4/inode.c:674 mpage_map_one_extent fs/ext4/inode.c:2421 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline] ext4_writepages+0x123f/0x3090 fs/ext4/inode.c:2842 do_writepages+0x473/0x6c0 mm/page-writeback.c:2388 filemap_fdatawrite_wbc+0x1f4/0x250 mm/filemap.c:409 __filemap_fdatawrite_range mm/filemap.c:442 [inline] file_write_and_wait_range+0x14d/0x220 mm/filemap.c:819 ext4_sync_file+0x1a9/0xa10 fs/ext4/fsync.c:151 vfs_fsync_range+0x190/0x1a0 fs/sync.c:188 generic_write_sync include/linux/fs.h:3038 [inline] ext4_buffered_write_iter+0x5d0/0x670 fs/ext4/file.c:277 ext4_file_write_iter+0x440/0x1540 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2212 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x835/0xfd0 fs/read_write.c:594 ksys_pwrite64 fs/read_write.c:701 [inline] __do_sys_pwrite64 fs/read_write.c:711 [inline] __se_sys_pwrite64 fs/read_write.c:708 [inline] __x64_sys_pwrite64+0x197/0x220 fs/read_write.c:708 x64_sys_call+0xa6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:19 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f6402a1e799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6401479028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007f6402c97fa0 RCX: 00007f6402a1e799 RDX: 00000000200000c1 RSI: 00002000000000c0 RDI: 000000000000000a RBP: 00007f6402ab4bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000009000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6402c98038 R14: 00007f6402c97fa0 R15: 00007ffcbcae96d8 Modules linked in: ---[ end trace 8bbd46c5eeb79f39 ]--- RIP: 0010:ext4_split_extent_at+0xe22/0xe40 fs/ext4/extents.c:3186 Code: ff ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c fc fb ff ff 4c 89 f7 49 89 d7 e8 bb e4 d2 ff 4c 89 fa e9 e9 fb ff ff e8 7e b6 93 ff <0f> 0b e8 77 b6 93 ff 0f 0b e8 70 b6 93 ff 0f 0b e8 69 b6 93 ff 0f RSP: 0018:ffffc90000ba6d00 EFLAGS: 00010283 RAX: ffffffff81d61682 RBX: 000000000000000e RCX: 0000000000080000 RDX: ffffc90002760000 RSI: 0000000000044fc6 RDI: 0000000000044fc7 RBP: ffffc90000ba6e78 R08: 0000000000000010 R09: 000000000000043b R10: dffffc0000000000 R11: ffffed10257342ea R12: dffffc0000000000 R13: 0000000000000072 R14: 0000000000000030 R15: 0000000000000010 FS: 00007f64014796c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f32709902f8 CR3: 000000012ba5d000 CR4: 00000000003526b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400