------------[ cut here ]------------
WARNING: CPU: 1 PID: 8966 at drivers/gpu/drm/vkms/vkms_crtc.c:21 vkms_vblank_simulate+0x150/0x154 drivers/gpu/drm/vkms/vkms_crtc.c:21
Modules linked in:
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 8966 Comm: kworker/1:0 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: ARM-Versatile Express
Workqueue: events nsim_dev_trap_report_work
Backtrace: 
[<81802550>] (dump_backtrace) from [<818027c4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:252)
 r7:00000080 r6:60000193 r5:00000000 r4:82b58344
[<818027ac>] (show_stack) from [<81809e98>] (__dump_stack lib/dump_stack.c:79 [inline])
[<818027ac>] (show_stack) from [<81809e98>] (dump_stack+0xb8/0xe8 lib/dump_stack.c:120)
[<81809de0>] (dump_stack) from [<81803358>] (panic+0x130/0x378 kernel/panic.c:231)
 r7:81f48198 r6:82a390a4 r5:00000000 r4:82c6b0d0
[<81803228>] (panic) from [<802446f4>] (__warn+0xb0/0x164 kernel/panic.c:605)
 r3:82a2248c r2:00000000 r1:00000000 r0:81f48198
 r7:00000015
[<80244644>] (__warn) from [<81803608>] (warn_slowpath_fmt+0x68/0xd4 kernel/panic.c:628)
 r7:809fa964 r6:00000015 r5:81fcbd70 r4:00000000
[<818035a4>] (warn_slowpath_fmt) from [<809fa964>] (vkms_vblank_simulate+0x150/0x154 drivers/gpu/drm/vkms/vkms_crtc.c:21)
 r8:00fe4c00 r7:83cea720 r6:82a22498 r5:00000000 r4:83ceb390
[<809fa814>] (vkms_vblank_simulate) from [<80307ebc>] (__run_hrtimer kernel/time/hrtimer.c:1537 [inline])
[<809fa814>] (vkms_vblank_simulate) from [<80307ebc>] (__hrtimer_run_queues+0xd4/0x690 kernel/time/hrtimer.c:1601)
 r9:86820000 r8:ddfdb3e0 r7:ddfdb380 r6:82a22498 r5:00000000 r4:83ceb390
[<80307de8>] (__hrtimer_run_queues) from [<80308da0>] (hrtimer_interrupt+0x14c/0x2e0 kernel/time/hrtimer.c:1663)
 r10:ddfdb4d8 r9:ddfdb498 r8:ddfdb458 r7:ddfdb4a0 r6:ddfdb4e0 r5:20000193
 r4:ddfdb380
[<80308c54>] (hrtimer_interrupt) from [<8114c308>] (timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline])
[<80308c54>] (hrtimer_interrupt) from [<8114c308>] (arch_timer_handler_virt+0x30/0x38 drivers/clocksource/arm_arch_timer.c:658)
 r10:86821d08 r9:86821d70 r8:86821cd8 r7:8348d940 r6:82a22c34 r5:0000001c
 r4:8348b000
[<8114c2d8>] (arch_timer_handler_virt) from [<802df904>] (handle_percpu_devid_irq+0xa4/0x19c kernel/irq/chip.c:930)
[<802df860>] (handle_percpu_devid_irq) from [<802d8730>] (generic_handle_irq_desc include/linux/irqdesc.h:158 [inline])
[<802df860>] (handle_percpu_devid_irq) from [<802d8730>] (generic_handle_irq kernel/irq/irqdesc.c:652 [inline])
[<802df860>] (handle_percpu_devid_irq) from [<802d8730>] (__handle_domain_irq+0xb0/0x120 kernel/irq/irqdesc.c:689)
 r10:86821d08 r9:86821d70 r8:00000001 r7:00000000 r6:828ad498 r5:00000000
 r4:828ad498 r3:00010001
[<802d8680>] (__handle_domain_irq) from [<8088af70>] (handle_domain_irq include/linux/irqdesc.h:176 [inline])
[<802d8680>] (__handle_domain_irq) from [<8088af70>] (gic_handle_irq+0x84/0xac drivers/irqchip/irq-gic.c:370)
 r10:60000013 r9:86820000 r8:e000200c r7:828ad4bc r6:e0002000 r5:86821d70
 r4:82a22c34
[<8088aeec>] (gic_handle_irq) from [<80200abc>] (__irq_svc+0x5c/0x94 arch/arm/kernel/entry-armv.S:205)
Exception stack(0x86821d70 to 0x86821db8)
1d60:                                     00000001 821137b8 20000093 002d1099
1d80: 834016c0 86706000 00000000 86821e08 86821e0c 86706000 60000013 86821df4
1da0: 86821d68 86821dc0 8181dacc 804af504 20000013 ffffffff
 r9:86820000 r8:86821e0c r7:86821da4 r6:ffffffff r5:20000013 r4:804af504
[<804af4a0>] (slab_free_freelist_hook) from [<804b30cc>] (slab_free mm/slub.c:3161 [inline])
[<804af4a0>] (slab_free_freelist_hook) from [<804b30cc>] (kfree+0xf8/0x4f8 mm/slub.c:4213)
 r10:81332f1c r9:86944160 r8:86944244 r7:86706f00 r6:86706000 r5:834016c0
 r4:de12e000
[<804b2fd4>] (kfree) from [<81332f1c>] (skb_free_head net/core/skbuff.c:650 [inline])
[<804b2fd4>] (kfree) from [<81332f1c>] (skb_release_data+0x170/0x174 net/core/skbuff.c:671)
 r10:85b6f000 r9:86944160 r8:86944244 r7:86706f00 r6:866d99c0 r5:85b7ca68
 r4:00000000
[<81332dac>] (skb_release_data) from [<81334be4>] (skb_release_all net/core/skbuff.c:725 [inline])
[<81332dac>] (skb_release_data) from [<81334be4>] (__kfree_skb net/core/skbuff.c:739 [inline])
[<81332dac>] (skb_release_data) from [<81334be4>] (consume_skb net/core/skbuff.c:895 [inline])
[<81332dac>] (skb_release_data) from [<81334be4>] (consume_skb+0x48/0x90 net/core/skbuff.c:889)
 r7:00000068 r6:81b6d95c r5:85b7ca68 r4:866d99c0
[<81334b9c>] (consume_skb) from [<80ce4ad8>] (nsim_dev_trap_report drivers/net/netdevsim/dev.c:586 [inline])
[<81334b9c>] (consume_skb) from [<80ce4ad8>] (nsim_dev_trap_report_work+0x2a8/0x318 drivers/net/netdevsim/dev.c:611)
 r5:85b7ca68 r4:866d99c0
[<80ce4830>] (nsim_dev_trap_report_work) from [<80269484>] (process_one_work+0x2d4/0x998 kernel/workqueue.c:2275)
 r10:00000008 r9:82a22498 r8:82bfd34e r7:ddfe6400 r6:ddfe2d00 r5:86d09780
 r4:85b6f000
[<802691b0>] (process_one_work) from [<80269bac>] (worker_thread+0x64/0x54c kernel/workqueue.c:2421)
 r10:00000008 r9:86820000 r8:82a06d00 r7:ddfe2d38 r6:86d09794 r5:ddfe2d00
 r4:86d09780
[<80269b48>] (worker_thread) from [<80271d20>] (kthread+0x184/0x1a4 kernel/kthread.c:292)
 r10:8695fe64 r9:86d09780 r8:80269b48 r7:00000000 r6:86820000 r5:86c267c0
 r4:86d09700
[<80271b9c>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:158)
Exception stack(0x86821fb0 to 0x86821ff8)
1fa0:                                     00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:80271b9c
 r4:86c267c0
Rebooting in 86400 seconds..