=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G L
-----------------------------
pr/ttyS0/32 is trying to lock:
ffff88807b839bc8 (&gpc->lock){....}-{3:3}, at: kvm_xen_set_evtchn_fast+0x208/0x8d0 arch/x86/kvm/xen.c:1872
other info that might help us debug this:
context-{2:2}
locks held by pr/ttyS0/32: 2, on CPU#1:
#0: ffffffff90033d78 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
#0: ffffffff90033d78 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:529 [inline]
#0: ffffffff90033d78 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
#1: ffff88807b83a118 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:249 [inline]
#1: ffff88807b83a118 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:356 [inline]
#1: ffff88807b83a118 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_set_evtchn_fast+0x1d2/0x8d0 arch/x86/kvm/xen.c:1870
stack backtrace:
CPU: 1 UID: 0 PID: 32 Comm: pr/ttyS0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_lock_invalid_wait_context kernel/locking/lockdep.c:4874 [inline]
check_wait_context kernel/locking/lockdep.c:4946 [inline]
__lock_acquire+0xf5b/0x2de0 kernel/locking/lockdep.c:5238
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
__raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
_raw_read_lock_irqsave+0x48/0x60 kernel/locking/spinlock.c:271
kvm_xen_set_evtchn_fast+0x208/0x8d0 arch/x86/kvm/xen.c:1872
xen_timer_callback+0x109/0x220 arch/x86/kvm/xen.c:139
__run_hrtimer kernel/time/hrtimer.c:2079 [inline]
__hrtimer_run_queues+0x371/0xa10 kernel/time/hrtimer.c:2136
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2255
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:221
Code: f7 e8 bd 42 9c f5 f7 c3 00 02 00 00 74 05 e8 d0 e1 c8 f5 9c 58 a9 00 02 00 00 75 29 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 84 34 8d f5 65 48 8b 05 bc e0 d8 08 48 85 c0 74 18 5b 41 5e e9
RSP: 0000:ffffc90000a87ca8 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000206 RCX: 8000000000000001
RDX: 0000000000000000 RSI: ffffffff8e6a7727 RDI: 0000000000000001
RBP: ffffc90000a87e18 R08: ffffffff91bdf8bf R09: 1ffffffff237bf17
R10: dffffc0000000000 R11: fffffbfff237bf18 R12: 0000000000000002
R13: ffff88801faabe80 R14: ffffffff9c205e40 R15: dffffc0000000000
nbcon_emit_one kernel/printk/nbcon.c:1165 [inline]
nbcon_kthread_func+0x724/0x8d0 kernel/printk/nbcon.c:1271
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
----------------
Code disassembly (best guess):
0: f7 e8 imul %eax
2: bd 42 9c f5 f7 mov $0xf7f59c42,%ebp
7: c3 ret
8: 00 02 add %al,(%rdx)
a: 00 00 add %al,(%rax)
c: 74 05 je 0x13
e: e8 d0 e1 c8 f5 call 0xf5c8e1e3
13: 9c pushf
14: 58 pop %rax
15: a9 00 02 00 00 test $0x200,%eax
1a: 75 29 jne 0x45
1c: f7 c3 00 02 00 00 test $0x200,%ebx
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 84 34 8d f5 call 0xf58d34b3 <-- trapping instruction
2f: 65 48 8b 05 bc e0 d8 mov %gs:0x8d8e0bc(%rip),%rax # 0x8d8e0f3
36: 08
37: 48 85 c0 test %rax,%rax
3a: 74 18 je 0x54
3c: 5b pop %rbx
3d: 41 5e pop %r14
3f: e9 .byte 0xe9