https://bugs.freedesktop.org/show_bug.cgi?id=110411

Bug ID: 110411 Summary: GUI lock up for KVM guest in drm_atomic_helper_commit_modeset_disables() Product: DRI Version: unspecified Hardware: PowerPC OS: Linux (All) Status: NEW Severity: normal Priority: medium Component: DRM/other Assignee: dri-devel@lists.freedesktop.org Reporter: dan@danny.cz

I see lock ups in KVM guests on Power9 HW on kernels 5.1 rc3 and rc4 with following in the kernel log

... dub 12 10:04:06 localhost.localdomain kernel: BUG: Unable to handle kernel instruction fetch (NULL pointer?) dub 12 10:04:06 localhost.localdomain kernel: Faulting instruction address: 0x00000000 dub 12 10:04:06 localhost.localdomain kernel: Oops: Kernel access of bad area, sig: 11 [#1] dub 12 10:04:06 localhost.localdomain kernel: LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=1024 NUMA pSeries dub 12 10:04:06 localhost.localdomain kernel: Modules linked in: xt_CHECKSUM ipt_MASQUERADE tun bridge stp llc kvm_hv kvm ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 > dub 12 10:04:06 localhost.localdomain kernel: CPU: 2 PID: 1136 Comm: Xorg Not tainted 5.1.0-0.rc4.git0.1.fc31.op.1.ppc64le #1 dub 12 10:04:06 localhost.localdomain kernel: NIP: 0000000000000000 LR: c008000002bb2bf4 CTR: 0000000000000000 dub 12 10:04:06 localhost.localdomain kernel: REGS: c0000001f2beb5e0 TRAP: 0400 Not tainted (5.1.0-0.rc4.git0.1.fc31.op.1.ppc64le) dub 12 10:04:06 localhost.localdomain kernel: MSR: 8000000040009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24882240 XER: 00000000 dub 12 10:04:06 localhost.localdomain kernel: CFAR: c008000002bb2bf0 IRQMASK: 0 GPR00: c008000002bb2904 c0000001f2beb870 c008000002bdc900 c0000000046de050 GPR04: 0000000000000003 000000000000001f c0000001fc6cf1b8 0000000000000001 GPR08: 00000000000e0000 0000000000000000 0000000000000001 c00800000289f238 GPR12: 0000000000000000 c00000000fffce00 0000000000000000 c0000001f1daa000 GPR16: 0000000000000001 0000000133e14880 ffffffffffffffff 0000000133796b90 GPR20: c0000001f2beba98 c0000001f7ebe000 c0000001f2bebc28 0000000133e0ac90 GPR24: c0000000032a5c00 c0000001f1daa000 c008000002c438e0 0000000000000001 GPR28: c0000001f1d63000 0000000000000000 c0000000046de050 c0000001f14a2400 dub 12 10:04:06 localhost.localdomain kernel: NIP [0000000000000000] (null) dub 12 10:04:06 localhost.localdomain kernel: LR [c008000002bb2bf4] drm_atomic_helper_commit_modeset_disables+0x4ac/0x510 [drm_kms_helper] dub 12 10:04:06 localhost.localdomain kernel: Call Trace: dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2beb910] [c008000002bb2f90] drm_atomic_helper_commit_tail+0x38/0xb0 [drm_kms_helper] dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2beb940] [c008000002bb30d8] commit_tail+0xd0/0xe0 [drm_kms_helper] dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2beb970] [c008000002bb3498] drm_atomic_helper_commit+0x1e0/0x1f0 [drm_kms_helper] dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2beb9b0] [c008000002841498] drm_atomic_commit+0x70/0xa0 [drm] dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2beba20] [c00800000285b068] drm_mode_atomic_ioctl+0x960/0xab8 [drm] dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2bebb60] [c00800000282888c] drm_ioctl_kernel+0xe4/0x190 [drm] dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2bebbc0] [c008000002828dc8] drm_ioctl+0x240/0x4a0 [drm] dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2bebd10] [c00000000041e4c0] do_vfs_ioctl+0x8a0/0xa50 dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2bebdb0] [c00000000041e734] ksys_ioctl+0xc4/0x110 dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2bebe00] [c00000000041e7a8] sys_ioctl+0x28/0x80 dub 12 10:04:06 localhost.localdomain kernel: [c0000001f2bebe20] [c00000000000b9e4] system_call+0x5c/0x70 dub 12 10:04:06 localhost.localdomain kernel: Instruction dump: dub 12 10:04:06 localhost.localdomain kernel: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX dub 12 10:04:06 localhost.localdomain kernel: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX dub 12 10:04:06 localhost.localdomain kernel: ---[ end trace 48e51fd2d6ea8877 ]---