=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G L
-----------------------------
swapper/0/0 is trying to lock:
ffff8880777b12e0 (&gpc->lock){....}-{3:3}, at: kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1819
other info that might help us debug this:
context-{2:2}
1 lock held by swapper/0/0:
#0: ffff8880777b1840 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#0: ffff8880777b1840 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#0: ffff8880777b1840 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_set_evtchn_fast+0x245/0xe80 arch/x86/kvm/xen.c:1817
stack backtrace:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_lock_invalid_wait_context kernel/locking/lockdep.c:4830 [inline]
check_wait_context kernel/locking/lockdep.c:4902 [inline]
__lock_acquire+0xfa4/0x2630 kernel/locking/lockdep.c:5187
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
__raw_read_lock_irqsave include/linux/rwlock_api_smp.h:172 [inline]
_raw_read_lock_irqsave+0x46/0x90 kernel/locking/spinlock.c:236
kvm_xen_set_evtchn_fast+0x253/0xe80 arch/x86/kvm/xen.c:1819
xen_timer_callback+0x1db/0x2a0 arch/x86/kvm/xen.c:140
__run_hrtimer kernel/time/hrtimer.c:1785 [inline]
__hrtimer_run_queues+0x1ad/0xa70 kernel/time/hrtimer.c:1849
hrtimer_interrupt+0x397/0x8c0 kernel/time/hrtimer.c:1911
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x109/0x490 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 88 81 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d a3 31 1a 00 fb f4 fc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e407e00 EFLAGS: 00000246
RAX: 000000000610cd41 RBX: ffffffff8e4975c0 RCX: ffffffff8b915c75
RDX: 0000000000000000 RSI: ffffffff8de7ad24 RDI: ffffffff8c1b1e20
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed101708679d
R10: ffff8880b8433ceb R11: 0000000000000000 R12: 0000000000000000
R13: fffffbfff1c92eb8 R14: 0000000000000000 R15: ffffffff90d9d310
arch_safe_halt arch/x86/include/asm/paravirt.h:73 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x464/0x590 kernel/sched/idle.c:352
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
rest_init+0x251/0x260 init/main.c:760
start_kernel+0x47f/0x480 init/main.c:1210
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148
----------------
Code disassembly (best guess):
0: 88 81 02 c3 cc cc mov %al,-0x33333cfe(%rcx)
6: cc int3
7: cc int3
8: 0f 1f 00 nopl (%rax)
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: 90 nop
18: 90 nop
19: 90 nop
1a: 90 nop
1b: f3 0f 1e fa endbr64
1f: 66 90 xchg %ax,%ax
21: 0f 00 2d a3 31 1a 00 verw 0x1a31a3(%rip) # 0x1a31cb
28: fb sti
29: f4 hlt
* 2a: e9 fc 35 03 00 jmp 0x3362b <-- trapping instruction
2f: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1)
36: 00 00 00
39: 66 90 xchg %ax,%ax
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop