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kernel BUG in ext4_split_extent_at

Status: upstream: reported C repro on 2023/06/09 05:14
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+5dde536eaf52fbd0073f@syzkaller.appspotmail.com
First crash: 531d, last: 70d
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (4)
Date Name Commit Repro Result
2024/04/19 android14-6.1 (ToT) dcb09569bbff C [report] kernel BUG in ext4_split_extent_at
2023/06/09 lts (merge base) b1644a0031cf C [report] kernel BUG in ext4_split_extent_at
2023/06/09 upstream (ToT) 33f2b5785a2b C [report] kernel BUG in ext4_split_extent_at
2024/04/19 upstream (ToT) dbe0a7be2838 C Didn't crash
▶ ▼ Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in ext4_split_extent_at ext4 1 1017d 1013d 0/28 auto-closed as invalid on 2022/06/08 01:32
android-5-10 kernel BUG in ext4_split_extent_at C error error 4 40d 531d 0/2 upstream: reported C repro on 2023/06/09 00:07
upstream kernel BUG in ext4_split_extent_at (2) ext4 C error done 3 332d 527d 25/28 fixed on 2024/01/30 15:47
android-5-15 kernel BUG in ext4_split_extent_at origin:upstream missing-backport syz error error 1 90d 531d 0/2 premoderation: reported syz repro on 2023/06/09 01:17
▶ ▼ Fix bisection attempts (13)
Created Duration User Patch Repo Result
2024/10/15 02:19 0m bisect fix android14-6.1 error job log
2024/09/12 07:10 2h00m bisect fix android14-6.1 OK (0) job log log
2024/08/09 14:06 1h39m bisect fix android14-6.1 OK (0) job log log
2024/06/29 16:23 1h28m bisect fix android14-6.1 OK (0) job log log
2024/05/24 02:25 1h25m bisect fix android14-6.1 OK (0) job log log
2024/03/31 00:52 1h50m bisect fix android14-6.1 OK (0) job log log
2024/02/29 17:00 1h33m bisect fix android14-6.1 OK (0) job log log
2024/01/20 14:50 1h34m bisect fix android14-6.1 OK (0) job log log
2023/12/21 07:22 3h03m bisect fix android14-6.1 OK (0) job log log
2023/11/20 17:46 1h39m bisect fix android14-6.1 OK (0) job log log
2023/10/20 08:38 1h27m bisect fix android14-6.1 OK (0) job log log
2023/09/18 21:37 1h54m bisect fix android14-6.1 OK (0) job log log
2023/07/12 02:15 3h28m bisect fix android14-6.1 OK (0) job log log

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/ext4/ext4_extents.h:200!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 1994 Comm: syz-executor331 Not tainted 6.1.25-syzkaller-00011-gf73aafc29bee #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:200 [inline]
RIP: 0010:ext4_split_extent_at+0x11d9/0x11f0 fs/ext4/extents.c:3222
Code: 4f ce ff 4c 8b 7c 24 18 48 8b 74 24 38 e9 b5 f9 ff ff e8 ba 6a 88 ff 0f 0b e8 b3 6a 88 ff 0f 0b e8 ec 66 1a 03 e8 a7 6a 88 ff <0f> 0b e8 a0 6a 88 ff 0f 0b e8 99 6a 88 ff 0f 0b 0f 1f 80 00 00 00
RSP: 0018:ffffc900035e6e60 EFLAGS: 00010293
RAX: ffffffff81eb55f9 RBX: 0000000000000000 RCX: ffff88811153e400
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900035e6fd8 R08: ffffffff81eb4942 R09: ffffed1023c47751
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881226c7010 R14: 0000000000000000 R15: ffff88810ba1af28
FS:  00007f63e3a2c700(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002003f000 CR3: 00000001111f8000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_split_extent+0x370/0x4e0 fs/ext4/extents.c:3385
 ext4_split_convert_extents fs/ext4/extents.c:3714 [inline]
 ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3876 [inline]
 ext4_ext_map_blocks+0x211e/0x71e0 fs/ext4/extents.c:4168
 ext4_map_blocks+0xa42/0x1ce0 fs/ext4/inode.c:651
 ext4_iomap_alloc fs/ext4/inode.c:3422 [inline]
 ext4_iomap_begin+0x824/0xd10 fs/ext4/inode.c:3472
 iomap_iter+0x5c1/0xbf0 fs/iomap/iter.c:74
 __iomap_dio_rw+0xddc/0x20a0 fs/iomap/direct-io.c:601
 iomap_dio_rw+0x41/0x90 fs/iomap/direct-io.c:690
 ext4_dio_write_iter fs/ext4/file.c:587 [inline]
 ext4_file_write_iter+0x1123/0x1cf0 fs/ext4/file.c:698
 call_write_iter include/linux/fs.h:2215 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x8d1/0xe80 fs/read_write.c:584
 ksys_write+0x199/0x2c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f63ebe621c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f63e3a2c2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000027 RCX: 00007f63ebe621c9
RDX: 0000000000000012 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f63ebee77b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f63ebee5140
R13: 00007f63ebee77b0 R14: 00007f63ebeb47b8 R15: 6f6f6c2f7665642f
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:200 [inline]
RIP: 0010:ext4_split_extent_at+0x11d9/0x11f0 fs/ext4/extents.c:3222
Code: 4f ce ff 4c 8b 7c 24 18 48 8b 74 24 38 e9 b5 f9 ff ff e8 ba 6a 88 ff 0f 0b e8 b3 6a 88 ff 0f 0b e8 ec 66 1a 03 e8 a7 6a 88 ff <0f> 0b e8 a0 6a 88 ff 0f 0b e8 99 6a 88 ff 0f 0b 0f 1f 80 00 00 00
RSP: 0018:ffffc900035e6e60 EFLAGS: 00010293
RAX: ffffffff81eb55f9 RBX: 0000000000000000 RCX: ffff88811153e400
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900035e6fd8 R08: ffffffff81eb4942 R09: ffffed1023c47751
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881226c7010 R14: 0000000000000000 R15: ffff88810ba1af28
FS:  00007f63e3a2c700(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f63e3a2c718 CR3: 00000001111f8000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/06/09 05:12 android14-6.1 f73aafc29bee 058b3a5a .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in ext4_split_extent_at
* Struck through repros no longer work on HEAD.