[syzbot] [kvmarm?] kernel panic: Unhandled exception

syzbot syzbot+d173b3985bd6b9487fa1 at syzkaller.appspotmail.com
Tue Sep 9 10:52:28 PDT 2025


Hello,

syzbot found the following issue on:

HEAD commit:    9c642e6226e3 Merge branch kvm-arm64/ffa-1.2 into kvmarm-ma..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
console output: https://syzkaller.appspot.com/x/log.txt?x=14f13562580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1b1bafe30fc85201
dashboard link: https://syzkaller.appspot.com/bug?extid=d173b3985bd6b9487fa1
compiler:       Debian clang version 20.1.8 (++20250708123704+0de59a293f7a-1~exp1~20250708003721.134), Debian LLD 20.1.8
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12f13562580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15104b12580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-9c642e62.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b5f8363adcc8/vmlinux-9c642e62.xz
kernel image: https://storage.googleapis.com/syzbot-assets/95eedfb6cbc9/Image-9c642e62.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d173b3985bd6b9487fa1 at syzkaller.appspotmail.com

x8 : 59f000001fc3bb00 x7 : ffff800080aba4c0 x6 : 0000000000000000
x5 : 0000000000000001 x4 : ffff80008e7e7ac0 x3 : 0000000000000004
x2 : 0000000000021d74 x1 : 0000000000000000 x0 : 00000000c600001b
Kernel panic - not syncing: Unhandled exception
CPU: 0 UID: 0 PID: 3618 Comm: syz.2.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: linux,dummy-virt (DT)
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0x30/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 vpanic+0x22c/0x59c kernel/panic.c:430
 vpanic+0x0/0x59c kernel/panic.c:566
 el1t_64_irq_handler+0x0/0x1c arch/arm64/kernel/entry-common.c:336
 el1_abort+0x0/0x5c arch/arm64/kernel/entry-common.c:635
 el1h_64_sync+0x6c/0x70 arch/arm64/kernel/entry.S:591
 pkvm_init_host_vm+0xb8/0x160 arch/arm64/kvm/pkvm.c:234 (P)
 kvm_arch_init_vm+0x150/0x288 arch/arm64/kvm/arm.c:187
 kvm_create_vm virt/kvm/kvm_main.c:1184 [inline]
 kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5480 [inline]
 kvm_dev_ioctl+0x838/0x105c virt/kvm/kvm_main.c:5522
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __arm64_sys_ioctl+0x18c/0x244 fs/ioctl.c:584
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x90/0x2b4 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x180/0x2f4 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x58/0x74 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x164 arch/arm64/kernel/entry-common.c:879
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
Kernel Offset: disabled
CPU features: 0x00000,000068c0,17de33e1,057ffe1f
Memory Limit: none

================================
WARNING: inconsistent lock state
syzkaller #0 Not tainted
--------------------------------
inconsistent {INITIAL USE} -> {IN-NMI} usage.
syz.2.17/3618 [HC1[1]:SC0[0]:HE0:SE1] takes:
f4f000000d3ed6e8 (&k->list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
f4f000000d3ed6e8 (&k->list_lock){+.+.}-{3:3}, at: bus_to_subsys drivers/base/bus.c:68 [inline]
f4f000000d3ed6e8 (&k->list_lock){+.+.}-{3:3}, at: bus_for_each_dev+0x60/0x2a4 drivers/base/bus.c:359
{INITIAL USE} state was registered at:
  lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
  __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
  _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154
  spin_lock include/linux/spinlock.h:351 [inline]
  kobj_kset_join lib/kobject.c:180 [inline]
  kobject_add_internal+0x46c/0xee4 lib/kobject.c:231
  kobject_add_varg lib/kobject.c:374 [inline]
  kobject_add+0x10c/0x1d0 lib/kobject.c:426
  device_add+0x494/0xd78 drivers/base/core.c:3627
  device_register+0x28/0x38 drivers/base/core.c:3771
  faux_bus_init+0x1c/0x88 drivers/base/faux.c:238
  driver_init+0x30/0x58 drivers/base/init.c:35
  do_basic_setup+0x1c/0xa8 init/main.c:1363
  kernel_init_freeable+0x244/0x330 init/main.c:1579
  kernel_init+0x24/0x1d0 init/main.c:1469
  ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
irq event stamp: 1602
hardirqs last  enabled at (1601): [<ffff80008658e000>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last  enabled at (1601): [<ffff80008658e000>] _raw_spin_unlock_irqrestore+0x44/0xbc kernel/locking/spinlock.c:194
hardirqs last disabled at (1602): [<ffff800086567f28>] __panic_unhandled+0x24/0x68 arch/arm64/kernel/entry-common.c:327
softirqs last  enabled at (1368): [<ffff8000800c8bec>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (1366): [<ffff8000800c8bb8>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&k->list_lock);
  <Interrupt>
    lock(&k->list_lock);

 *** DEADLOCK ***

no locks held by syz.2.17/3618.

stack backtrace:
CPU: 0 UID: 0 PID: 3618 Comm: syz.2.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: linux,dummy-virt (DT)
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0x30/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_usage_bug+0x2f4/0x32c kernel/locking/lockdep.c:4042
 verify_lock_unused+0x78/0x88 kernel/locking/lockdep.c:5792
 lock_acquire+0x22c/0x2e0 kernel/locking/lockdep.c:5859
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 bus_to_subsys drivers/base/bus.c:68 [inline]
 bus_for_each_dev+0x60/0x2a4 drivers/base/bus.c:359
 coresight_panic_cb+0x2c/0x3c drivers/hwtracing/coresight/coresight-core.c:1586
 notifier_call_chain+0x1e8/0x65c kernel/notifier.c:85
 atomic_notifier_call_chain+0xd0/0x180 kernel/notifier.c:223
 vpanic+0x2c4/0x59c kernel/panic.c:459
 vpanic+0x0/0x59c kernel/panic.c:566
 el1t_64_irq_handler+0x0/0x1c arch/arm64/kernel/entry-common.c:336
 el1_abort+0x0/0x5c arch/arm64/kernel/entry-common.c:635
 el1h_64_sync+0x6c/0x70 arch/arm64/kernel/entry.S:591
 pkvm_init_host_vm+0xb8/0x160 arch/arm64/kvm/pkvm.c:234 (P)
 kvm_arch_init_vm+0x150/0x288 arch/arm64/kvm/arm.c:187
 kvm_create_vm virt/kvm/kvm_main.c:1184 [inline]
 kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5480 [inline]
 kvm_dev_ioctl+0x838/0x105c virt/kvm/kvm_main.c:5522
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __arm64_sys_ioctl+0x18c/0x244 fs/ioctl.c:584
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x90/0x2b4 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x180/0x2f4 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x58/0x74 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x164 arch/arm64/kernel/entry-common.c:879
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
Rebooting in 86400 seconds..


---
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