=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G L
-----------------------------
syz.0.967/9187 is trying to lock:
ffff888033f85bb0 (&gpc->lock){....}-{3:3}, at: kvm_xen_set_evtchn_fast+0x1f4/0x9a0 arch/x86/kvm/xen.c:1822
other info that might help us debug this:
context-{2:2}
locks held by syz.0.967/9187: 4, last CPU#1:
#0: ffff88802c2a5428 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x27f/0xfd0 virt/kvm/kvm_main.c:4438
#1: ffff888033f85b30 (&kvm->arch.xen.xen_lock){+.+.}-{4:4}, at: kvm_xen_vcpu_set_attr+0x4d/0x1190 arch/x86/kvm/xen.c:910
#2: ffff888033f86110 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#2: ffff888033f86110 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#2: ffff888033f86110 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_vcpu_set_attr+0x8e/0x1190 arch/x86/kvm/xen.c:911
#3: ffff888033f86110 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#3: ffff888033f86110 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#3: ffff888033f86110 (&kvm->srcu){.?.+}-{0:0}, at: kvm_xen_set_evtchn_fast+0x1bc/0x9a0 arch/x86/kvm/xen.c:1820
stack backtrace:
CPU: 1 UID: 0 PID: 9187 Comm: syz.0.967 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_lock_invalid_wait_context kernel/locking/lockdep.c:4846 [inline]
check_wait_context kernel/locking/lockdep.c:4918 [inline]
__lock_acquire+0xe39/0x2cf0 kernel/locking/lockdep.c:5203
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886
__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+0x1f4/0x9a0 arch/x86/kvm/xen.c:1822
xen_timer_callback+0x109/0x220 arch/x86/kvm/xen.c:140
__run_hrtimer kernel/time/hrtimer.c:2067 [inline]
__hrtimer_run_queues+0x371/0xa10 kernel/time/hrtimer.c:2124
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2243
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 1d cb f5 f7 c3 00 02 00 00 74 05 e8 c0 2b f7 f5 9c 58 a9 00 02 00 00 75 29 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 a4 3f bc f5 65 48 8b 05 4c d0 96 07 48 85 c0 74 18 5b 41 5e e9
RSP: 0018:ffffc9001b5cf3c8 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000246 RCX: 8000000000000001
RDX: 0000000000000007 RSI: ffffffff8e23923c RDI: 0000000000000001
RBP: ffffc9001b5cf508 R08: ffffffff90583737 R09: 1ffffffff20b06e6
R10: dffffc0000000000 R11: fffffbfff20b06e7 R12: 0000004441556d50
R13: ffff88802c2a69c0 R14: ffff8880b8728180 R15: dffffc0000000000
hrtimer_start include/linux/hrtimer.h:222 [inline]
kvm_xen_start_timer+0x37f/0x5f0 arch/x86/kvm/xen.c:309
kvm_xen_vcpu_set_attr+0xaf6/0x1190 arch/x86/kvm/xen.c:1127
kvm_arch_vcpu_ioctl+0x16e7/0x3080 arch/x86/kvm/x86.c:6612
kvm_vcpu_ioctl+0x7e3/0xfd0 virt/kvm/kvm_main.c:4647
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: 0033:0x7f60a039e0d9
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:00007f60a12e8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f60a0625fa0 RCX: 00007f60a039e0d9
RDX: 0000200000000100 RSI: 000000004048aecb RDI: 0000000000000005
RBP: 00007f60a0435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f60a0626038 R14: 00007f60a0625fa0 R15: 00007f60a074fa48
----------------
Code disassembly (best guess):
0: f7 e8 imul %eax
2: bd 1d cb f5 f7 mov $0xf7f5cb1d,%ebp
7: c3 ret
8: 00 02 add %al,(%rdx)
a: 00 00 add %al,(%rax)
c: 74 05 je 0x13
e: e8 c0 2b f7 f5 call 0xf5f72bd3
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 a4 3f bc f5 call 0xf5bc3fd3 <-- trapping instruction
2f: 65 48 8b 05 4c d0 96 mov %gs:0x796d04c(%rip),%rax # 0x796d083
36: 07
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