kern/54999: kernel panic in drm gem cma code

[coypu%sdf.org@localhost]

>Number:         54999
>Category:       kern
>Synopsis:       kernel panic in drm gem cma code
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Feb 21 23:00:00 +0000 2020
>Originator:     coypu
>Release:        NetBSD 9.99.47
>Organization:
>Environment:
NetBSD arm64 9.99.47 NetBSD 9.99.47 (GENERIC64) #0: Fri Feb 21 17:12:50 UTC 2020  fly@ovh:/home/fedora/arm64/sys/arch/evbarm/compile/GENERIC64 evbarm

>Description:
Switch between vt and xorg somewhat quickly. Obtain panic.

panic: Trap: Data Abort (EL1): Translation Fault L1 with read access for 0000000000000058: pc ffffffc0000826f4: opcode b9405820: ldr w0, [x1,#88]

cpu1: Begin traceback...
trace fp ffffffc0556cf680
fp ffffffc0556cf6a0 vpanic() at ffffffc0004aece8 netbsd:vpanic+0x160
fp ffffffc0556cf710 panic() at ffffffc0004aeddc netbsd:panic+0x44
fp ffffffc0556cf7a0 data_abort_handler() at ffffffc0000889dc netbsd:data_abort_handler+0x49c
tf ffffffc0556cf820 el1_trap() at ffffffc00008538c netbsd:el1_trap
---- trapframe 0xffffffc0556cf820 (304 bytes) ----
    pc=ffffffc0000826f4,   spsr=0000000060000005
   esr=0000000096000005,    far=0000000000000058
    x0=ffff0000bf965208,     x1=0000000000000000
    x2=ffffffc054a00000,     x3=00000000007e9000
    x4=0000000000000000,     x5=0000000000000000
    x6=ffffffc0000826c8,     x7=ffff0000bf659c80
    x8=0000000000000004,     x9=0000000000000001
   x10=0000000000000000,    x11=000000000000003f
   x12=fffffc0001f54c35,    x13=fffffc0001f54c35
   x14=00000002002e7648,    x15=ffff00007d530d50
   x16=0000f1061e4ee300,    x17=0000f1061dd55558
   x18=0000000000000006,    x19=0000000000000000
   x20=00000000007e9000,    x21=0000000000000000
   x22=ffffffc054a00000,    x23=ffff0000bf965208
   x24=0000000000000000,    x25=ffffffc0556cfcb0
   x26=ffffffc0556cfcb0,    x27=ffffffc0556cfda0
   x28=0000000080000000, fp=x29=ffffffc0556cfb50
lr=x30=ffffffc0003161b8,     sp=ffffffc0556cfb50
------------------------------------------------
fp ffffffc0556cfb50 _bus_dmamap_load() at ffffffc0000826f4 netbsd:_bus_dmamap_load+0x2c
fp ffffffc0556cfba0 drm_gem_cma_create_internal() at ffffffc0003161b4 netbsd:drm_gem_cma_create_internal+0xd4
fp ffffffc0556cfbf0 drm_gem_cma_dumb_create() at ffffffc000316634 netbsd:drm_gem_cma_dumb_create+0x4c
fp ffffffc0556cfc50 drm_ioctl() at ffffffc00033c5e0 netbsd:drm_ioctl+0x130
fp ffffffc0556cfd30 drm_ioctl_shim() at ffffffc000315860 netbsd:drm_ioctl_shim+0x38
fp ffffffc0556cfd40 sys_ioctl() at ffffffc0004bbfe4 netbsd:sys_ioctl+0x404
fp ffffffc0556cfe20 syscall() at ffffffc000086d64 netbsd:syscall+0x18c
tf ffffffc0556cfed0 el0_trap() at ffffffc0000853f8 netbsd:el0_trap
---- trapframe 0xffffffc0556cfed0 (304 bytes) ----
    pc=0000f1061dd5555c,   spsr=0000000060000000
   esr=0000000056000036,    far=0000f1061dba8200
    x0=000000000000000a,     x1=00000000c02064b2
    x2=0000ffffffe473c0,     x3=0000f1061e70b218
    x4=0000ffffffe473cc,     x5=000000000021e3b0
    x6=0000000000000000,     x7=0000f1061e62a0c0
    x8=0000f1061e629ca8,     x9=0000000000000006
   x10=0000000000000040,    x11=0000000000000001
   x12=00000002002e74e0,    x13=00000002002e76d0
   x14=00000002002e7648,    x15=0000f1061d72b6e0
   x16=0000f1061e4ee300,    x17=0000f1061dd55558
   x18=0000000000000006,    x19=0000f1061d72b6c0
   x20=0000ffffffe473c0,    x21=00000000c02064b2
   x22=000000000000000a,    x23=000000000000000a
   x24=0000f1061d8f97a0,    x25=00000002003a8090
   x26=00000002003b0db0,    x27=00000002003a7000
   x28=0000000000000000, fp=x29=0000ffffffe47350
lr=x30=0000f1061e4d7480,     sp=0000ffffffe47350
------------------------------------------------
cpu1: End traceback...

dump to dev 92,17 not possible
rebooting...

>How-To-Repeat:

>Fix: