=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G L
-----------------------------
syz.1.8537/1246 is trying to lock:
ffff888031771bc8 (&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 syz.1.8537/1246: 4, last CPU#0:
#0: ffff88805560d1a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x27f/0xfd0 virt/kvm/kvm_main.c:4543
#1: ffff888031771b48 (&kvm->arch.xen.xen_lock){+.+.}-{4:4}, at: kvm_xen_vcpu_set_attr+0x4d/0x1230 arch/x86/kvm/xen.c:939
#2: ffff888031772118 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:213 [inline]
#2: ffff888031772118 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:320 [inline]
#2: ffff888031772118 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_vcpu_set_attr+0x8e/0x1230 arch/x86/kvm/xen.c:940
#3: ffff888031772118 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:213 [inline]
#3: ffff888031772118 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:320 [inline]
#3: ffff888031772118 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_set_evtchn_fast+0x1d2/0x8d0 arch/x86/kvm/xen.c:1870
stack backtrace:
CPU: 0 UID: 0 PID: 1246 Comm: syz.1.8537 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
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:2075 [inline]
__hrtimer_run_queues+0x371/0xa10 kernel/time/hrtimer.c:2132
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2251
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 5d 40 a2 f5 f7 c3 00 02 00 00 74 05 e8 30 d7 ce f5 9c 58 a9 00 02 00 00 75 29 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 e4 39 93 f5 65 48 8b 05 dc 40 bc 08 48 85 c0 74 18 5b 41 5e c3
RSP: 0018:ffffc90006def3e8 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000246 RCX: 8000000000000001
RDX: 0000000000000007 RSI: ffffffff8e69a4ba RDI: 0000000000000001
RBP: ffffc90006def528 R08: ffffffff919cf7bf R09: 1ffffffff2339ef7
R10: dffffc0000000000 R11: fffffbfff2339ef8 R12: 000001afca71678f
R13: ffff88805560e638 R14: ffff8880b8228600 R15: dffffc0000000000
hrtimer_start include/linux/hrtimer.h:222 [inline]
kvm_xen_start_timer+0x37f/0x5f0 arch/x86/kvm/xen.c:308
kvm_xen_vcpu_set_attr+0xb29/0x1230 arch/x86/kvm/xen.c:1166
kvm_arch_vcpu_ioctl+0x148b/0x23a0 arch/x86/kvm/x86.c:3843
kvm_vcpu_ioctl+0x7e3/0xfd0 virt/kvm/kvm_main.c:4752
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1376f9f559
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:00007f13751f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1377226090 RCX: 00007f1376f9f559
RDX: 0000200000000100 RSI: 000000004048aecb RDI: 0000000000000008
RBP: 00007f1377036b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1377226128 R14: 00007f1377226090 R15: 00007f137734fa48
----------------
Code disassembly (best guess):
0: f7 e8 imul %eax
2: 5d pop %rbp
3: 40 a2 f5 f7 c3 00 02 rex movabs %al,0x7400000200c3f7f5
a: 00 00 74
d: 05 e8 30 d7 ce add $0xced730e8,%eax
12: f5 cmc
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 e4 39 93 f5 call 0xf5933a13 <-- trapping instruction
2f: 65 48 8b 05 dc 40 bc mov %gs:0x8bc40dc(%rip),%rax # 0x8bc4113
36: 08
37: 48 85 c0 test %rax,%rax
3a: 74 18 je 0x54
3c: 5b pop %rbx
3d: 41 5e pop %r14
3f: c3 ret