syzbot


kernel BUG in ext4_split_extent_at

Status: premoderation: reported syz repro on 2023/06/09 01:17
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+d3e8517ccdcb149f2553@syzkaller.appspotmail.com
First crash: 405d, last: 34d
Cause bisection: failed (error log, bisect log)
  
Bug presence (4)
Date Name Commit Repro Result
2024/04/19 android13-5.15-lts (ToT) ad06eaf051cd C [report] kernel BUG in ext4_split_extent_at
2023/06/09 lts (merge base) d86dfc4d95cd C [report] kernel BUG in ext4_split_extent_at
2023/06/09 upstream (ToT) 8d15d5e1851b C [report] kernel BUG in ext4_split_extent_at
2024/04/19 upstream (ToT) 2668e3ae2ef3 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 891d 887d 0/27 auto-closed as invalid on 2022/06/08 01:32
android-5-10 kernel BUG in ext4_split_extent_at C error error 4 55d 405d 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 206d 401d 26/27 fixed on 2024/01/30 15:47
android-6-1 kernel BUG in ext4_split_extent_at origin:upstream missing-backport C error 1 18d 405d 0/2 upstream: reported C repro on 2023/06/09 05:14
Fix bisection attempts (7)
Created Duration User Patch Repo Result
2024/06/14 05:25 1h06m bisect fix android13-5.15-lts OK (0) job log log
2024/03/20 16:02 1h09m bisect fix android13-5.15-lts OK (0) job log log
2024/02/11 17:35 1h00m bisect fix android13-5.15-lts OK (0) job log log
2023/12/29 21:10 1h08m bisect fix android13-5.15-lts OK (0) job log log
2023/11/27 15:29 1h23m bisect fix android13-5.15-lts OK (0) job log log
2023/10/28 10:56 1h00m bisect fix android13-5.15-lts OK (0) job log log
2023/07/16 20:39 1h24m bisect fix android13-5.15-lts 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: 0 PID: 1147 Comm: syz-executor.5 Not tainted 5.15.106-syzkaller-00249-g19c0ed55a470 #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+0x10d2/0x10f0 fs/ext4/extents.c:3221
Code: f9 cf ff 4c 8b 74 24 70 48 8b 74 24 38 e9 4a fa ff ff e8 f1 b1 8e ff 0f 0b e8 ea b1 8e ff 0f 0b e8 f3 aa d9 02 e8 de b1 8e ff <0f> 0b e8 d7 b1 8e ff 0f 0b e8 d0 b1 8e ff 0f 0b 66 2e 0f 1f 84 00
RSP: 0018:ffffc900021d6e40 EFLAGS: 00010293
RAX: ffffffff81e139e2 RBX: 0000000000000000 RCX: ffff8881147d13c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900021d6fb8 R08: ffffffff81e12dd8 R09: ffffed1024521ba5
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff888114732600 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007fc501760700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002003f000 CR3: 000000011da68000 CR4: 00000000003506b0
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+0x2147/0x7250 fs/ext4/extents.c:4168
 ext4_map_blocks+0xaa7/0x1e30 fs/ext4/inode.c:646
 ext4_iomap_alloc fs/ext4/inode.c:3427 [inline]
 ext4_iomap_begin+0x824/0xd10 fs/ext4/inode.c:3477
 iomap_iter+0x5b5/0xbe0 fs/iomap/iter.c:74
 __iomap_dio_rw+0xb3a/0x1ed0 fs/iomap/direct-io.c:593
 iomap_dio_rw+0x3e/0x90 fs/iomap/direct-io.c:680
 ext4_dio_write_iter fs/ext4/file.c:576 [inline]
 ext4_file_write_iter+0x1142/0x1cc0 fs/ext4/file.c:687
 call_write_iter include/linux/fs.h:2159 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xd8a/0x1160 fs/read_write.c:594
 ksys_write+0x199/0x2c0 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:656
 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+0x61/0xcb
RIP: 0033:0x7fc509fce169
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007fc501760168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc50a0ee050 RCX: 00007fc509fce169
RDX: 0000000000000012 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007fc50a029ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffebe20efef R14: 00007fc501760300 R15: 0000000000022000
 </TASK>
Modules linked in:
---[ end trace 3f5cf2bf4cbc2007 ]---
RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:200 [inline]
RIP: 0010:ext4_split_extent_at+0x10d2/0x10f0 fs/ext4/extents.c:3221
Code: f9 cf ff 4c 8b 74 24 70 48 8b 74 24 38 e9 4a fa ff ff e8 f1 b1 8e ff 0f 0b e8 ea b1 8e ff 0f 0b e8 f3 aa d9 02 e8 de b1 8e ff <0f> 0b e8 d7 b1 8e ff 0f 0b e8 d0 b1 8e ff 0f 0b 66 2e 0f 1f 84 00
RSP: 0018:ffffc900021d6e40 EFLAGS: 00010293
RAX: ffffffff81e139e2 RBX: 0000000000000000 RCX: ffff8881147d13c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900021d6fb8 R08: ffffffff81e12dd8 R09: ffffed1024521ba5
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff888114732600 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007fc501760700(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8d08474180 CR3: 000000011da68000 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 01:16 android13-5.15-lts 19c0ed55a470 058b3a5a .config console log report syz [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-15 kernel BUG in ext4_split_extent_at
* Struck through repros no longer work on HEAD.