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From: syzbot <syzbot+fc3a448093c17a792368@syzkaller.appspotmail.com>
To: arnd@arndb.de, clemens@ladisch.de, gregkh@linuxfoundation.org,
	 linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [kernel?] WARNING in hpet_read
Date: Fri, 31 Jul 2026 17:34:22 -0700	[thread overview]
Message-ID: <6a6d3f0e.f794c993.27aeb.000b.GAE@google.com> (raw)

Hello,

syzbot found the following issue on:

HEAD commit:    3b5f4b83c4ab Merge tag 'for-7.2-rc5-tag' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=166438c6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=fc3a448093c17a792368
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-3b5f4b83.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ed6d6b480fd7/vmlinux-3b5f4b83.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5a591a74024/bzImage-3b5f4b83.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fc3a448093c17a792368@syzkaller.appspotmail.com

------------[ cut here ]------------
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff85a8f43b>] 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#2: syz.1.801/8558
Modules linked in:
CPU: 2 UID: 0 PID: 8558 Comm: syz.1.801 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 1a 50 0f 48 89 d1 <67> 48 0f b9 3a eb db e8 9d 34 a5 00 eb 9f 89 74 24 04 e8 c2 34 a5
RSP: 0018:ffffc90004597bc0 EFLAGS: 00010282
RAX: dffffc0000000000 RBX: ffffffff8c5307a0 RCX: ffffffff85a8f43b
RDX: ffffffff85a8f43b RSI: 0000000000000001 RDI: ffffffff9125ce30
RBP: 0000000000000135 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88802a984a80
R13: 0000000000000000 R14: ffff88802d6bb880 R15: ffffed1005530c5e
FS:  00007f9517ad76c0(0000) GS:ffff8880d5fdc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9517ad6ff8 CR3: 0000000041f16000 CR4: 0000000000352ef0
DR0: 0000000000000005 DR1: 0000000000000005 DR2: 0000000000040004
DR3: 000000000000000a 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: 0033:0x7f9516b9de99
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:00007f9517ad7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f9516e26090 RCX: 00007f9516b9de99
RDX: 0000000000002020 RSI: 0000200000000d40 RDI: 0000000000000005
RBP: 00007f9516c33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9516e26128 R14: 00007f9516e26090 R15: 00007ffc906d2838
 </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 1a 50 0f 	lea    0xf501a0c(%rip),%rdi        # 0xf501a33
  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 9d 34 a5 00       	call   0xa534d3
  36:	eb 9f                	jmp    0xffffffd7
  38:	89 74 24 04          	mov    %esi,0x4(%rsp)
  3c:	e8                   	.byte 0xe8
  3d:	c2 34 a5             	ret    $0xa534


---
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                 reply	other threads:[~2026-08-01  0:34 UTC|newest]

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