Re: [syzbot] [usb?] WARNING in spcp8x5_get_msr

[Johan Hovold <johan@kernel.org>]

On Wed, Aug 05, 2026 at 05:00:34PM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    848acc8ffe1b Merge tag 'fsverity-for-linus' of git://git.k..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17602cc6580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
> dashboard link: https://syzkaller.appspot.com/bug?extid=3b514b87202742f22c44
> compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12193e32580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1224e3b9580000
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-848acc8f.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/6fb497cc0c8d/vmlinux-848acc8f.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/663ccee34982/bzImage-848acc8f.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3b514b87202742f22c44@syzkaller.appspotmail.com
> 
> SPCP8x5 ttyUSB0: failed to set control lines: -32
> ------------[ cut here ]------------
> do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff81e258b8>] prepare_to_wait+0x98/0x380 kernel/sched/wait.c:256
> WARNING: kernel/sched/core.c:9120 at __might_sleep+0x94/0xc0 kernel/sched/core.c:9120, CPU#0: syz.0.17/5924
> Modules linked in:
> CPU: 0 UID: 0 PID: 5924 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
> 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 27 50 0f 48 89 d1 <67> 48 0f b9 3a eb db e8 9d 3a a5 00 eb 9f 89 74 24 04 e8 c2 3a a5
> RSP: 0018:ffffc90003a27558 EFLAGS: 00010286
> RAX: dffffc0000000000 RBX: ffffffff8e193c49 RCX: ffffffff81e258b8
> RDX: ffffffff81e258b8 RSI: 0000000000000001 RDI: ffffffff9125db30
> RBP: 0000000000000143 R08: 0000000000000001 R09: 000000000000015a
> R10: 0000000000000200 R11: 0000000000000000 R12: ffff8880255fa540
> R13: 0000000000000001 R14: ffffffff87b453a0 R15: dffffc0000000000
> FS:  00007fcdef59c6c0(0000) GS:ffff8880d5dd8000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fcdeddfed58 CR3: 000000002b0b3000 CR4: 0000000000352ef0
> Call Trace:
>  <TASK>
>  might_alloc include/linux/sched/mm.h:323 [inline]
>  slab_pre_alloc_hook mm/slub.c:4537 [inline]
>  slab_alloc_node mm/slub.c:4897 [inline]
>  __kmalloc_cache_noprof+0x3fd/0x6c0 mm/slub.c:5485
>  _kmalloc_noprof include/linux/slab.h:988 [inline]
>  _kzalloc_noprof include/linux/slab.h:1309 [inline]
>  spcp8x5_get_msr+0xe9/0x2d0 drivers/usb/serial/spcp8x5.c:197
>  spcp8x5_carrier_raised+0x75/0xe0 drivers/usb/serial/spcp8x5.c:243
>  serial_port_carrier_raised+0x8f/0xd0 drivers/usb/serial/usb-serial.c:757
>  tty_port_carrier_raised drivers/tty/tty_port.c:441 [inline]
>  tty_port_block_til_ready+0x43f/0x910 drivers/tty/tty_port.c:559
>  tty_port_open+0x19c/0x1f0 drivers/tty/tty_port.c:775
>  tty_open+0x3dd/0xfa0 drivers/tty/tty_io.c:2137

Just sent a fix here:

	https://lore.kernel.org/all/20260806135248.129482-1-johan@kernel.org/

Johan