general protection fault in start_creating

Status: upstream: reported on 2026/08/19 20:46
Reported-by: syzbot+489204306b2bf26cd786@syzkaller.appspotmail.com
First crash: 9d22h, last: 9d22h
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in start_creating fs 2 syz, C done 106 2255d 2285d 15/29 fixed on 2020/07/17 17:58
android-5-15 general protection fault in start_creating 2 2 7d00h 7d14h 0/2 premoderation: reported on 2026/08/22 04:50

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000002a: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000150-0x0000000000000157]
CPU: 1 PID: 4805 Comm: syz.4.129 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__lock_acquire+0xf8/0x7b50 kernel/locking/lockdep.c:4882
Code: 42 0f b6 04 00 84 c0 0f 85 2d 64 00 00 83 3d d2 6b 2e 0c 00 0f 84 ee 26 00 00 83 3d e1 00 c2 0a 00 74 2a 4c 89 e8 48 c1 e8 03 <42> 80 3c 00 00 74 12 4c 89 ef e8 f9 40 61 00 49 b8 00 00 00 00 00
RSP: 0018:ffffc9000409f460 EFLAGS: 00010002
RAX: 000000000000002a RBX: 0000000000000000 RCX: 1ffff92000813eac
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000150
RBP: ffffc9000409f690 R08: dffffc0000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1b1631e R12: 0000000000000001
R13: 0000000000000150 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fd34da096c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000035000 CR3: 000000005fd24000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 inode_lock include/linux/fs.h:787 [inline]
 start_creating+0x129/0x310 fs/debugfs/inode.c:350
 __debugfs_create_file+0x6f/0x500 fs/debugfs/inode.c:399
 debugfs_create_files block/blk-mq-debugfs.c:821 [inline]
 blk_mq_debugfs_register_ctx block/blk-mq-debugfs.c:872 [inline]
 blk_mq_debugfs_register_hctx+0x66e/0x7b0 block/blk-mq-debugfs.c:891
 blk_mq_debugfs_register+0x4a5/0x7e0 block/blk-mq-debugfs.c:843
 blk_register_queue+0x204/0x3a0 block/blk-sysfs.c:878
 device_add_disk+0x589/0xd00 block/genhd.c:490
 null_add_dev+0xe81/0x1630 drivers/block/null_blk/main.c:1913
 nullb_device_power_store+0x241/0x370 drivers/block/null_blk/main.c:390
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x30b/0x400 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2173 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd34f7b10d9
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:00007fd34da09028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd34fa38fa0 RCX: 00007fd34f7b10d9
RDX: 0000000000000002 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fd34f848024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd34fa39038 R14: 00007fd34fa38fa0 R15: 00007ffe70df1618
 </TASK>
Modules linked in:
---[ end trace 694cae515577443c ]---
RIP: 0010:__lock_acquire+0xf8/0x7b50 kernel/locking/lockdep.c:4882
Code: 42 0f b6 04 00 84 c0 0f 85 2d 64 00 00 83 3d d2 6b 2e 0c 00 0f 84 ee 26 00 00 83 3d e1 00 c2 0a 00 74 2a 4c 89 e8 48 c1 e8 03 <42> 80 3c 00 00 74 12 4c 89 ef e8 f9 40 61 00 49 b8 00 00 00 00 00
RSP: 0018:ffffc9000409f460 EFLAGS: 00010002
RAX: 000000000000002a RBX: 0000000000000000 RCX: 1ffff92000813eac
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000150
RBP: ffffc9000409f690 R08: dffffc0000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1b1631e R12: 0000000000000001
R13: 0000000000000150 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fd34da096c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000035000 CR3: 000000005fd24000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	42 0f b6 04 00       	movzbl (%rax,%r8,1),%eax
   5:	84 c0                	test   %al,%al
   7:	0f 85 2d 64 00 00    	jne    0x643a
   d:	83 3d d2 6b 2e 0c 00 	cmpl   $0x0,0xc2e6bd2(%rip)        # 0xc2e6be6
  14:	0f 84 ee 26 00 00    	je     0x2708
  1a:	83 3d e1 00 c2 0a 00 	cmpl   $0x0,0xac200e1(%rip)        # 0xac20102
  21:	74 2a                	je     0x4d
  23:	4c 89 e8             	mov    %r13,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 00 00       	cmpb   $0x0,(%rax,%r8,1) <-- trapping instruction
  2f:	74 12                	je     0x43
  31:	4c 89 ef             	mov    %r13,%rdi
  34:	e8 f9 40 61 00       	call   0x614132
  39:	49                   	rex.WB
  3a:	b8 00 00 00 00       	mov    $0x0,%eax

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/19 20:45 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in start_creating
* Struck through repros no longer work on HEAD.