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kernel BUG in ext4_split_extent_at

Status: upstream: reported C repro on 2023/06/09 00:07
Reported-by: syzbot+1257631df4d42447d768@syzkaller.appspotmail.com
First crash: 1162d, last: 6d01h
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in ext4_split_extent_at ext4 -1 1 1435d 1430d 0/29 auto-closed as invalid on 2022/06/08 01:32
upstream kernel BUG in ext4_split_extent_at (2) ext4 -1 C error done 3 750d 944d 25/29 fixed on 2024/01/30 15:47
android-6-1 kernel BUG in ext4_split_extent_at missing-backport origin:upstream -1 C error error 1 487d 949d 0/2 auto-obsoleted due to no activity on 2024/12/21 09:12
android-6-1 kernel BUG in ext4_split_extent_at (2) origin:lts -1 C done 1 182d 182d 0/2 auto-obsoleted due to no activity on 2025/10/22 23:15
upstream kernel BUG in ext4_split_extent_at (3) ext4 -1 3 185d 200d 0/29 auto-obsoleted due to no activity on 2025/10/19 20:03
android-5-15 kernel BUG in ext4_split_extent_at missing-backport origin:lts -1 C error error 2 24d 229d 0/2 upstream: reported C repro on 2025/05/29 02:28
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/01/03 02:08 10m retest repro android13-5.10-lts report log
2026/01/03 02:08 13m retest repro android13-5.10-lts report log
2026/01/03 02:08 18m retest repro android13-5.10-lts report log
2026/01/03 02:08 13m retest repro android13-5.10-lts report log
2025/12/11 11:22 14m retest repro android13-5.10-lts report log
2025/12/11 11:22 40m retest repro android13-5.10-lts report log
2025/11/24 02:02 12m retest repro android13-5.10-lts OK log
2025/10/19 09:18 14m retest repro android13-5.10-lts report log
2025/10/19 09:18 7m retest repro android13-5.10-lts report log
2025/10/02 03:18 5m retest repro android13-5.10-lts report log

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:3181!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 11006 Comm: syz.5.1822 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ext4_split_extent_at+0xe4c/0xe70 fs/ext4/extents.c:3181
Code: fb ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c c0 fb ff ff 48 89 df 49 89 f6 e8 a1 5d d3 ff 4c 89 f6 e9 ad fb ff ff e8 34 6f 99 ff <0f> 0b e8 2d 6f 99 ff 0f 0b e8 26 6f 99 ff 0f 0b e8 1f 6f 99 ff 0f
RSP: 0018:ffffc90004e5ec80 EFLAGS: 00010293
RAX: ffffffff81ca354c RBX: 0000000000000027 RCX: ffff88811d06a780
RDX: 0000000000000000 RSI: 0000000000000027 RDI: 000000000000004d
RBP: ffffc90004e5edf0 R08: 0000000000000017 R09: 000000000000043b
R10: ffffed10253ecf2a R11: 1ffff110253ecf28 R12: 0000000000000017
R13: 0000000000000030 R14: 0000000000008001 R15: 0000000000000030
FS:  00007f07d88106c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb9cd557d58 CR3: 0000000110f65000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_split_extent+0x386/0x4e0 fs/ext4/extents.c:3380
 ext4_split_convert_extents fs/ext4/extents.c:3709 [inline]
 ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3870 [inline]
 ext4_ext_map_blocks+0x1084/0x5d80 fs/ext4/extents.c:4225
 ext4_map_blocks+0x978/0x1bc0 fs/ext4/inode.c:674
 mpage_map_one_extent fs/ext4/inode.c:2452 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline]
 ext4_writepages+0x11d5/0x2e00 fs/ext4/inode.c:2873
 do_writepages+0x12a/0x270 mm/page-writeback.c:2380
 __filemap_fdatawrite_range+0x2bc/0x360 mm/filemap.c:427
 filemap_write_and_wait_range+0x65/0x290 mm/filemap.c:660
 ext4_punch_hole+0x120/0xad0 fs/ext4/inode.c:4118
 ext4_fallocate+0x271/0x1a70 fs/ext4/extents.c:4758
 vfs_fallocate+0x4b4/0x590 fs/open.c:310
 madvise_remove mm/madvise.c:880 [inline]
 madvise_vma_behavior mm/madvise.c:904 [inline]
 madvise_walk_vmas mm/madvise.c:1131 [inline]
 do_madvise+0x12cf/0x1df0 mm/madvise.c:1308
 __do_sys_madvise mm/madvise.c:1322 [inline]
 __se_sys_madvise mm/madvise.c:1320 [inline]
 __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1320
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f07d89c1749
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:00007f07d8810038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f07d8c18090 RCX: 00007f07d89c1749
RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000200000000000
RBP: 00007f07d8a45f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f07d8c18128 R14: 00007f07d8c18090 R15: 00007ffcef5b49c8
Modules linked in:
---[ end trace 398ff4898059485f ]---
RIP: 0010:ext4_split_extent_at+0xe4c/0xe70 fs/ext4/extents.c:3181
Code: fb ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c c0 fb ff ff 48 89 df 49 89 f6 e8 a1 5d d3 ff 4c 89 f6 e9 ad fb ff ff e8 34 6f 99 ff <0f> 0b e8 2d 6f 99 ff 0f 0b e8 26 6f 99 ff 0f 0b e8 1f 6f 99 ff 0f
RSP: 0018:ffffc90004e5ec80 EFLAGS: 00010293
RAX: ffffffff81ca354c RBX: 0000000000000027 RCX: ffff88811d06a780
RDX: 0000000000000000 RSI: 0000000000000027 RDI: 000000000000004d
RBP: ffffc90004e5edf0 R08: 0000000000000017 R09: 000000000000043b
R10: ffffed10253ecf2a R11: 1ffff110253ecf28 R12: 0000000000000017
R13: 0000000000000030 R14: 0000000000008001 R15: 0000000000000030
FS:  00007f07d88106c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000110f65000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/19 01:24 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2025/02/12 08:04 android13-5.10-lts 6686f2996d23 f2baddf5 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2023/06/09 00:04 android13-5.10-lts 43c801dc3325 058b3a5a .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2026/01/06 12:32 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2025/12/19 23:59 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2025/02/12 06:47 android13-5.10-lts 6686f2996d23 f2baddf5 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2022/12/14 02:28 android12-5.10-lts 202ee063496e f6511626 .config strace log report syz [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2026/01/07 04:12 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2025/06/22 17:06 android13-5.10-lts d76d4cd0623a d6cdfb8a .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2025/05/29 13:35 android13-5.10-lts cf6ed0f1511d 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2025/04/02 00:26 android13-5.10-lts 094fc3778d6b b8645499 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2025/02/27 03:27 android13-5.10-lts 3f5f2283d684 6a8fcbc4 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2023/06/08 22:36 android13-5.10-lts 43c801dc3325 058b3a5a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_split_extent_at
2022/11/08 00:29 android12-5.10-lts 0118fb827bc7 6feb842b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_split_extent_at
* Struck through repros no longer work on HEAD.