syzbot

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kernel BUG at fs/ext4/extents.c:2142!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 551 Comm: syz.3.48 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_ext_insert_extent+0x4790/0x47d0 fs/ext4/extents.c:2142
Code: ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c c6 e8 ff ff 4c 89 f7 e8 e1 52 d1 ff e9 b9 e8 ff ff e8 b7 20 8c ff 0f 0b e8 b0 20 8c ff <0f> 0b e8 a9 20 8c ff 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 40
RSP: 0018:ffffc900019c6560 EFLAGS: 00010293
RAX: ffffffff81e54c50 RBX: ffff88813482c400 RCX: ffff88811d3d3cc0
RDX: 0000000000000000 RSI: 00000000000000b6 RDI: 00000000000000b6
RBP: ffffc900019c6710 R08: ffff888115e0234f R09: 1ffff11022bc0469
R10: dffffc0000000000 R11: ffffed1022bc046a R12: 00000000000000b6
R13: ffff8881341d4050 R14: ffff88813482c538 R15: 00000000000000b6
FS:  000055556e642500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffe70 CR3: 000000011e2b6000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_split_extent_at+0x7d4/0xf70 fs/ext4/extents.c:3236
 ext4_split_extent+0x1ba/0x4c0 fs/ext4/extents.c:3355
 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+0x10e5/0x61d0 fs/ext4/extents.c:4231
 ext4_map_blocks+0x9d8/0x1b70 fs/ext4/inode.c:679
 mpage_map_one_extent fs/ext4/inode.c:2435 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2488 [inline]
 ext4_writepages+0x1409/0x30e0 fs/ext4/inode.c:2856
 do_writepages+0x3a4/0x5f0 mm/page-writeback.c:2494
 filemap_fdatawrite_wbc+0x128/0x190 mm/filemap.c:408
 __filemap_fdatawrite_range mm/filemap.c:441 [inline]
 file_write_and_wait_range+0x159/0x230 mm/filemap.c:794
 ext4_sync_file+0x1a9/0xa10 fs/ext4/fsync.c:151
 vfs_fsync_range+0x1a1/0x1b0 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2980 [inline]
 ext4_buffered_write_iter+0x573/0x630 fs/ext4/file.c:292
 ext4_file_write_iter+0x191/0x1500 fs/ext4/file.c:-1
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_write+0x665/0xb40 fs/read_write.c:861
 vfs_iter_write+0x7d/0xa0 fs/read_write.c:902
 iter_file_splice_write+0x69e/0xcd0 fs/splice.c:685
 do_splice_from fs/splice.c:763 [inline]
 direct_splice_actor+0xf7/0x130 fs/splice.c:930
 splice_direct_to_actor+0x4ad/0xb30 fs/splice.c:885
 do_splice_direct+0x1c2/0x2d0 fs/splice.c:973
 do_sendfile+0x5ed/0xea0 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x199/0x1f0 fs/read_write.c:1309
 x64_sys_call+0x62c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcb7c79c799
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:00007ffe6abb4fb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fcb7ca15fa0 RCX: 00007fcb7c79c799
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007fcb7c832bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000003ffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb7ca15fac R14: 00007fcb7ca15fa0 R15: 00007fcb7ca15fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_insert_extent+0x4790/0x47d0 fs/ext4/extents.c:2142
Code: ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c c6 e8 ff ff 4c 89 f7 e8 e1 52 d1 ff e9 b9 e8 ff ff e8 b7 20 8c ff 0f 0b e8 b0 20 8c ff <0f> 0b e8 a9 20 8c ff 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 40
RSP: 0018:ffffc900019c6560 EFLAGS: 00010293
RAX: ffffffff81e54c50 RBX: ffff88813482c400 RCX: ffff88811d3d3cc0
RDX: 0000000000000000 RSI: 00000000000000b6 RDI: 00000000000000b6
RBP: ffffc900019c6710 R08: ffff888115e0234f R09: 1ffff11022bc0469
R10: dffffc0000000000 R11: ffffed1022bc046a R12: 00000000000000b6
R13: ffff8881341d4050 R14: ffff88813482c538 R15: 00000000000000b6
FS:  000055556e642500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555680e44e8 CR3: 000000011e2b6000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400