=============================
[ BUG: Invalid wait context ]
syzkaller #0 Tainted: G L
-----------------------------
syz.0.331/7068 is trying to lock:
ffff888058bdd2d0 (&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}
2 locks held by syz.0.331/7068:
#0: ffff888039b9e1c8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11d/0x590 mm/mmap_lock.c:310
#1: ffff888058bdd850 (&kvm->srcu){.?.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#1: ffff888058bdd850 (&kvm->srcu){.?.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#1: ffff888058bdd850 (&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: 7068 Comm: syz.0.331 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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+0x1b1/0x370 kernel/locking/lockdep.c:5825
__raw_read_lock_irqsave include/linux/rwlock_api_smp.h:174 [inline]
_raw_read_lock_irqsave+0x46/0x90 kernel/locking/spinlock.c:240
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:1930 [inline]
__hrtimer_run_queues+0x142/0xa00 kernel/time/hrtimer.c:1994
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:native_pmd_val arch/x86/include/asm/pgtable_types.h:401 [inline]
RIP: 0010:pmd_none arch/x86/include/asm/pgtable.h:1010 [inline]
RIP: 0010:__handle_mm_fault+0x6b2/0x2a00 mm/memory.c:6525
Code: 89 fe e8 d1 af ab ff 4d 85 ff 0f 85 9b 04 00 00 e8 e3 b4 ab ff 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 85 b7 16 00 00 48 8b 2b 31 ff 48 83 e5 9f 48 89 ee e8 97 af ab
RSP: 0000:ffffc900038d7c78 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffff8880563e6708 RCX: ffffffff825cfcef
RDX: 1ffff1100ac7cce1 RSI: ffffffff825cfcfd RDI: ffff888026c30000
RBP: ffff8880563e7aa8 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff888039b9e140 R15: 0000000000000000
handle_mm_fault+0x36d/0xa20 mm/memory.c:6734
do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f0f56f619dc
Code: 48 8d 15 67 c4 28 00 48 8d 0c 1e 49 39 d0 49 89 48 60 0f 95 c2 48 29 d8 0f b6 d2 48 83 c8 01 48 c1 e2 02 48 09 da 48 83 ca 01 <48> 89 56 08 48 89 41 08 48 8d 4e 10 eb b0 48 8d 0d a7 d9 0c 00 ba
RSP: 002b:00007ffdabfc8bb0 EFLAGS: 00010206
RAX: 00000000000204e1 RBX: 0000000000000120 RCX: 000055555c3ceb20
RDX: 0000000000000121 RSI: 000055555c3cea00 RDI: 0000000000000004
RBP: 0000000000000010 R08: 00007f0f571ede20 R09: 0000000000000001
R10: 0000000000021000 R11: 0000000000000000 R12: 0000000000000110
R13: 0000000000000000 R14: 00007f0f571ede80 R15: 0000000000000120
----------------
Code disassembly (best guess):
0: 89 fe mov %edi,%esi
2: e8 d1 af ab ff call 0xffabafd8
7: 4d 85 ff test %r15,%r15
a: 0f 85 9b 04 00 00 jne 0x4ab
10: e8 e3 b4 ab ff call 0xffabb4f8
15: 48 89 da mov %rbx,%rdx
18: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1f: fc ff df
22: 48 c1 ea 03 shr $0x3,%rdx
26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
* 2a: 0f 85 b7 16 00 00 jne 0x16e7 <-- trapping instruction
30: 48 8b 2b mov (%rbx),%rbp
33: 31 ff xor %edi,%edi
35: 48 83 e5 9f and $0xffffffffffffff9f,%rbp
39: 48 89 ee mov %rbp,%rsi
3c: e8 .byte 0xe8
3d: 97 xchg %eax,%edi
3e: af scas %es:(%rdi),%eax
3f: ab stos %eax,%es:(%rdi)