WARNING in spcp8x5_get_msr

Status: upstream: reported C repro on 2026/08/29 04:43
Reported-by: syzbot+cfb963fd0a2755ba9b85@syzkaller.appspotmail.com
First crash: 3d13h, last: 2d18h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in spcp8x5_get_msr -1 syz, C 12 2d20h 3d08h 0/3 upstream: reported C repro on 2026/08/29 09:36
linux-6.1 WARNING in spcp8x5_get_msr -1 syz 2 2d18h 2d19h 0/3 upstream: reported syz repro on 2026/08/29 22:38
upstream WARNING in spcp8x5_get_msr prio:low usb -1 syz, C 103 3d21h 26d 21/29 upstream: reported C repro on 2026/08/06 00:00

Sample crash report:
SPCP8x5 ttyUSB0: failed to set control lines: -110
SPCP8x5 ttyUSB0: Set UART format 0x30b failed (error = -32)
SPCP8x5 ttyUSB0: failed to set control lines: -32
SPCP8x5 ttyUSB0: Set UART format 0x107 failed (error = -32)
SPCP8x5 ttyUSB0: failed to set control lines: -32
------------[ cut here ]------------
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8165d2f1>] prepare_to_wait+0x171/0x200 kernel/sched/wait.c:277
WARNING: CPU: 1 PID: 5934 at kernel/sched/core.c:10139 __might_sleep+0xa6/0xe0 kernel/sched/core.c:-1
Modules linked in:
CPU: 1 PID: 5934 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__might_sleep+0xa6/0xe0 kernel/sched/core.c:10135
Code: 5d e9 5e 00 00 00 c6 05 e6 60 18 0d 01 48 89 fb 48 c7 c7 20 5d ca 8a 41 89 f6 89 ee 48 89 ca e8 20 97 f2 ff 48 89 df 44 89 f6 <0f> 0b eb c9 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 77 ff ff ff 49
RSP: 0018:ffffc90003407438 EFLAGS: 00010246
RAX: ad46e1db5d491000 RBX: ffffffff8c81ce0a RCX: ffff88802e0bbc00
RDX: 0000000000000000 RSI: 0000000000000132 RDI: ffffffff8c81ce0a
RBP: 0000000000000001 R08: ffffc90003407047 R09: 1ffff92000680e08
R10: dffffc0000000000 R11: fffff52000680e09 R12: 0000000000000000
R13: 00000000ffffffff R14: 0000000000000132 R15: dffffc0000000000
FS:  00007f770ce2a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056268ff95300 CR3: 00000000738c0000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 might_alloc include/linux/sched/mm.h:306 [inline]
 slab_pre_alloc_hook+0x4a/0x300 mm/slab.h:714
 slab_alloc_node mm/slub.c:3477 [inline]
 __kmem_cache_alloc_node+0x53/0x250 mm/slub.c:3534
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 spcp8x5_get_msr+0xd3/0x2a0 drivers/usb/serial/spcp8x5.c:209
 spcp8x5_carrier_raised+0x31/0x80 drivers/usb/serial/spcp8x5.c:255
 serial_port_carrier_raised+0x86/0xb0 drivers/usb/serial/usb-serial.c:762
 tty_port_carrier_raised drivers/tty/tty_port.c:448 [inline]
 tty_port_block_til_ready+0x443/0x8a0 drivers/tty/tty_port.c:567
 tty_open+0x48c/0xcc0 drivers/tty/tty_io.c:2144
 chrdev_open+0x58c/0x600 fs/char_dev.c:414
 do_dentry_open+0x880/0x14b0 fs/open.c:929
 do_open fs/namei.c:3683 [inline]
 path_openat+0x284f/0x3270 fs/namei.c:3844
 do_filp_open+0x1f2/0x430 fs/namei.c:3871
 do_sys_openat2+0x134/0x1d0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f770bf9e159
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:00007f770ce2a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f770c225fa0 RCX: 00007f770bf9e159
RDX: 0000000000000041 RSI: 0000200000000b00 RDI: ffffffffffffff9c
RBP: 00007f770c035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f770c226038 R14: 00007f770c225fa0 R15: 00007ffee5db0288
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/29 11:58 linux-6.6.y a4a971135a2f 2f52988a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in spcp8x5_get_msr
2026/08/29 23:38 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in spcp8x5_get_msr
2026/08/29 23:38 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in spcp8x5_get_msr
2026/08/29 19:13 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in spcp8x5_get_msr
2026/08/29 19:12 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in spcp8x5_get_msr
2026/08/29 04:43 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in spcp8x5_get_msr
* Struck through repros no longer work on HEAD.