kernel BUG in ext4_ext_insert_extent

Status: auto-obsoleted due to no activity on 2026/10/18 22:51
Reported-by: syzbot+e67f274f1d95b6782e59@syzkaller.appspotmail.com
First crash: 390d, last: 165d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in ext4_ext_insert_extent (2) prio:high ext4 -1 syz, C done error 38 219d 555d 0/29 auto-obsoleted due to no activity on 2026/09/04 00:06
android-54 kernel BUG in ext4_ext_insert_extent -1 1 1728d 1728d 0/2 auto-closed as invalid on 2022/05/24 20:39
upstream kernel BUG in ext4_ext_insert_extent ext4 -1 1 2054d 2050d 0/29 auto-closed as invalid on 2021/06/02 20:11
android-6-1 kernel BUG in ext4_ext_insert_extent origin:upstream missing-backport -1 syz error 9 201d 247d 0/2 auto-obsoleted due to no activity on 2026/10/11 15:30
android-5-15 kernel BUG in ext4_ext_insert_extent origin:upstream missing-backport -1 syz, C error 13 166d 253d 0/2 auto-obsoleted due to no activity on 2026/08/16 07:33
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/10/18 22:35 16m retest repro android13-5.10-lts no crash job log log
2026/09/03 05:49 38m retest repro android13-5.10-lts no crash job log log
2026/09/03 05:49 17m retest repro android13-5.10-lts no crash job log log
2026/09/03 05:49 19m retest repro android13-5.10-lts no crash job log log
2026/09/03 05:49 11m retest repro android13-5.10-lts no crash job log log
2026/09/03 05:49 11m retest repro android13-5.10-lts no crash job log log
2026/08/25 16:09 13m retest repro android13-5.10-lts no crash job log log
2026/08/25 16:09 13m retest repro android13-5.10-lts no crash job log log
2026/08/25 16:09 15m retest repro android13-5.10-lts no crash job log log
2026/08/25 16:09 15m retest repro android13-5.10-lts no crash job log log

Sample crash report:
EXT4-fs (loop2): pa ffff88813458a2a0: logic 16, phys. 177, len 21
EXT4-fs error (device loop2): ext4_mb_release_inode_pa:4367: group 0, free 19, pa_free 18
------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:2135!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 1891 Comm: syz.2.412 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:ext4_ext_insert_extent+0x4592/0x45d0 fs/ext4/extents.c:2135
Code: ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c 08 e9 ff ff 48 89 df e8 ff 50 d4 ff e9 fb e8 ff ff e8 75 cf 99 ff 0f 0b e8 6e cf 99 ff <0f> 0b e8 67 cf 99 ff 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 30
RSP: 0018:ffffc90000d560e0 EFLAGS: 00010293
RAX: ffffffff81cae782 RBX: ffff888140996400 RCX: ffff888112164f00
RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000010
RBP: ffffc90000d56290 R08: ffff88811cbc8f1f R09: 1ffff110239791e3
R10: dffffc0000000000 R11: ffffed10239791e4 R12: 0000000000000010
R13: 1ffff110215d7f88 R14: ffff888140996424 R15: 0000000000000010
FS:  00007f69fd7596c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8e2ae614c0 CR3: 000000010f335000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_ext_map_blocks+0x1709/0x5e00 fs/ext4/extents.c:4372
 ext4_map_blocks+0x985/0x1bd0 fs/ext4/inode.c:674
 _ext4_get_block+0x1d1/0x4e0 fs/ext4/inode.c:817
 ext4_get_block_unwritten+0x2a/0x40 fs/ext4/inode.c:848
 ext4_block_write_begin+0x573/0x1340 fs/ext4/inode.c:1101
 ext4_write_begin+0x67e/0x1690 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x478/0xf10 fs/ext4/inode.c:3033
 generic_perform_write+0x2ce/0x540 mm/filemap.c:3509
 ext4_buffered_write_iter+0x4b8/0x640 fs/ext4/file.c:271
 ext4_file_write_iter+0x53f/0x1980 fs/ext4/file.c:-1
 __kernel_write+0x535/0x910 fs/read_write.c:550
 dump_emit+0x246/0x370 fs/coredump.c:855
 dump_user_range+0x6a/0x1a0 fs/coredump.c:908
 elf_core_dump+0x2866/0x2cc0 fs/binfmt_elf.c:2290
 do_coredump+0x1ba3/0x28e0 fs/coredump.c:817
 get_signal+0xf23/0x12e0 kernel/signal.c:2779
 arch_do_signal_or_restart+0xe2/0x11d0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199
 irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:287
 irqentry_exit+0x12/0x60 kernel/entry/common.c:375
 exc_general_protection+0x1ca/0x250 arch/x86/kernel/traps.c:557
 asm_exc_general_protection+0x1e/0x30 arch/x86/include/asm/idtentry.h:565
RIP: 0033:0x7f69fecfede1
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:00002000000000b0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f69fef77fa0 RCX: 00007f69fecfedd9
RDX: 00002000000000c0 RSI: 00002000000000b0 RDI: 0000000000008400
RBP: 00007f69fed94d69 R08: 0000200000000180 R09: 0000200000000180
R10: 0000200000000100 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f69fef78038 R14: 00007f69fef77fa0 R15: 00007ffd69e7e288
Modules linked in:
---[ end trace 412407d5e7c16e24 ]---
RIP: 0010:ext4_ext_insert_extent+0x4592/0x45d0 fs/ext4/extents.c:2135
Code: ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c 08 e9 ff ff 48 89 df e8 ff 50 d4 ff e9 fb e8 ff ff e8 75 cf 99 ff 0f 0b e8 6e cf 99 ff <0f> 0b e8 67 cf 99 ff 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 30
RSP: 0018:ffffc90000d560e0 EFLAGS: 00010293
RAX: ffffffff81cae782 RBX: ffff888140996400 RCX: ffff888112164f00
RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000010
RBP: ffffc90000d56290 R08: ffff88811cbc8f1f R09: 1ffff110239791e3
R10: dffffc0000000000 R11: ffffed10239791e4 R12: 0000000000000010
R13: 1ffff110215d7f88 R14: ffff888140996424 R15: 0000000000000010
FS:  00007f69fd7596c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056426aa3daf8 CR3: 000000010f335000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/06 17:46 android13-5.10-lts 95a92a883bae 1dddfd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/03/07 02:47 android13-5.10-lts 9a301c292a32 5cb44a80 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/03/07 02:02 android13-5.10-lts 9a301c292a32 5cb44a80 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/03/05 21:56 android13-5.10-lts dad37bbb13a8 d20b04c8 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/03/04 01:02 android13-5.10-lts dad37bbb13a8 4180d919 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/03/04 00:19 android13-5.10-lts dad37bbb13a8 4180d919 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/02/22 17:12 android13-5.10-lts e8b14e1cefe8 6e7b5511 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/02/22 13:57 android13-5.10-lts e8b14e1cefe8 6e7b5511 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2026/02/22 13:30 android13-5.10-lts e8b14e1cefe8 6e7b5511 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2025/12/19 12:24 android13-5.10-lts e253c52bbdfc d6526ea3 .config console log report syz / log [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_ext_insert_extent
2025/09/23 23:01 android13-5.10-lts 911f602c2237 e667a34f .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
2025/09/23 22:41 android13-5.10-lts 911f602c2237 e667a34f .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_ext_insert_extent
* Struck through repros no longer work on HEAD.