WARNING in hpet_read

Status: upstream: reported on 2026/08/01 00:34
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+fc3a448093c17a792368@syzkaller.appspotmail.com
First crash: 11d, last: 21h15m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
dfe657b6 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ WARNING in hpet_read 2026/07/30 00:00 2026/07/30 00:00 2026/07/30 00:49 2377cd3d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] WARNING in hpet_read 0 (1) 2026/08/01 00:34

Sample crash report:
ntfs3: Unknown parameter ''
------------[ cut here ]------------
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff85a89f8b>] hpet_read+0x21b/0x6a0 drivers/char/hpet.c:285
WARNING: kernel/sched/core.c:9120 at __might_sleep+0x94/0xc0 kernel/sched/core.c:9120, CPU#0: syz.3.1644/11381
Modules linked in:
CPU: 0 UID: 0 PID: 11381 Comm: syz.3.1644 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__might_sleep+0x97/0xc0 kernel/sched/core.c:9120
Code: 8b 94 24 70 18 00 00 48 85 d2 75 14 48 83 c4 08 89 ee 48 89 df 31 d2 5b 5d 41 5c e9 33 fc ff ff 48 8d 3d 0c 30 4f 0f 48 89 d1 <67> 48 0f b9 3a eb db e8 5d 3c a5 00 eb 9f 89 74 24 04 e8 82 3c a5
RSP: 0018:ffffc90005d6fbc0 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: ffffffff8c52f500 RCX: ffffffff85a89f8b
RDX: ffffffff85a89f8b RSI: 0000000000000001 RDI: ffffffff9124e430
RBP: 0000000000000135 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880235a2540
R13: 0000000000000000 R14: ffff8880385fb340 R15: ffffed10046b47b6
FS:  00007f8a4a2c06c0(0000) GS:ffff8880d5dec000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5b0b027dac CR3: 0000000038681000 CR4: 0000000000352ef0
DR0: 00000000000006c5 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __might_fault+0x8b/0x140 mm/memory.c:7290
 hpet_read+0x56f/0x6a0 drivers/char/hpet.c:309
 vfs_read+0x1e4/0xb40 fs/read_write.c:572
 ksys_read+0x12a/0x250 fs/read_write.c:716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8a4939e0d9
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:00007f8a4a2c0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f8a49626090 RCX: 00007f8a4939e0d9
RDX: 0000000000000037 RSI: 0000200000000080 RDI: 0000000000000003
RBP: 00007f8a49435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8a49626128 R14: 00007f8a49626090 R15: 00007fff6c6daf28
 </TASK>
----------------
Code disassembly (best guess):
   0:	8b 94 24 70 18 00 00 	mov    0x1870(%rsp),%edx
   7:	48 85 d2             	test   %rdx,%rdx
   a:	75 14                	jne    0x20
   c:	48 83 c4 08          	add    $0x8,%rsp
  10:	89 ee                	mov    %ebp,%esi
  12:	48 89 df             	mov    %rbx,%rdi
  15:	31 d2                	xor    %edx,%edx
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	41 5c                	pop    %r12
  1b:	e9 33 fc ff ff       	jmp    0xfffffc53
  20:	48 8d 3d 0c 30 4f 0f 	lea    0xf4f300c(%rip),%rdi        # 0xf4f3033
  27:	48 89 d1             	mov    %rdx,%rcx
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb db                	jmp    0xc
  31:	e8 5d 3c a5 00       	call   0xa53c93
  36:	eb 9f                	jmp    0xffffffd7
  38:	89 74 24 04          	mov    %esi,0x4(%rsp)
  3c:	e8                   	.byte 0xe8
  3d:	82                   	(bad)
  3e:	3c a5                	cmp    $0xa5,%al

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/07 12:42 upstream f9a2394a2348 e4ef95d6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in hpet_read
2026/07/28 19:42 upstream 3b5f4b83c4ab 4a865b71 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in hpet_read
2026/07/28 09:53 upstream 62cc90241548 4a865b71 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in hpet_read
* Struck through repros no longer work on HEAD.