[23981.997415] ------------[ cut here ]------------
[23981.997494] WARNING: CPU: 4 PID: 0 at drivers/gpu/drm/nouveau/nvkm/subdev/mc/base.c:51 nvkm_mc_intr+0xf7/0x100 [nouveau]
[23981.997499] Modules linked in: fuse ntfs vfat msdos fat dm_mod iptable_filter ip_tables x_tables binfmt_misc bridge stp llc snd_hda_codec_hdmi joydev snd_hda_codec_via ppdev evdev nouveau snd_hda_codec_generic video mxm_wmi ttm snd_cmipci snd_hda_intel snd_mpu401_uart kvm_amd snd_opl3_lib sp5100_tco snd_rawmidi drm_kms_helper snd_hda_codec edac_mce_amd kvm snd_seq_device snd_hda_core serio_raw pcspkr edac_core k10temp irqbypass gameport snd_hwdep drm i2c_piix4 snd_pcm i2c_algo_bit i2c_core snd_timer fb_sys_fops snd syscopyarea sysfillrect sg sysimgblt soundcore parport_pc parport asus_atk0110 acpi_cpufreq wmi tpm_tis tpm button shpchp processor hid_generic usbhid hid sd_mod ata_generic ohci_pci psmouse pata_atiixp ahci ohci_hcd ehci_pci libahci ehci_hcd libata usbcore scsi_mod r8169 usb_common mii
[23981.997603] CPU: 4 PID: 0 Comm: swapper/4 Tainted: G        W       4.6.0-rc2-x32 #1
[23981.997608] Hardware name: System manufacturer System Product Name/M4A77T, BIOS 2401    05/18/2011
[23981.997613]  0000000000000000 ffffffff813352bf 0000000000000000 0000000000000000
[23981.997621]  ffffffff81050302 ffffffffa04f2b20 ffff88022b816980 ffff88022b816980
[23981.997627]  ffff88022d84b800 000000000000001b ffff88022d8e1400 ffffffffa04654f7
[23981.997634] Call Trace:
[23981.997637]  <IRQ>  [<ffffffff813352bf>] ? dump_stack+0x46/0x67
[23981.997655]  [<ffffffff81050302>] ? __warn+0xe2/0x100
[23981.997710]  [<ffffffffa04654f7>] ? nvkm_mc_intr+0xf7/0x100 [nouveau]
[23981.997764]  [<ffffffffa046943c>] ? nvkm_pci_intr+0x3c/0x70 [nouveau]
[23981.997773]  [<ffffffff810989fd>] ? handle_irq_event_percpu+0x5d/0xf0
[23981.997780]  [<ffffffff81098ab8>] ? handle_irq_event+0x28/0x50
[23981.997787]  [<ffffffff81038069>] ? apic_ack_edge+0x39/0x60
[23981.997793]  [<ffffffff8109be91>] ? handle_edge_irq+0x71/0x130
[23981.997800]  [<ffffffff8101aa24>] ? handle_irq+0x14/0x20
[23981.997806]  [<ffffffff8101a365>] ? do_IRQ+0x55/0xf0
[23981.997812]  [<ffffffff8159f6bf>] ? common_interrupt+0x7f/0x7f
[23981.997815]  <EOI>  [<ffffffff8102191d>] ? amd_e400_idle+0x2d/0xb0
[23981.997826]  [<ffffffff8102191b>] ? amd_e400_idle+0x2b/0xb0
[23981.997833]  [<ffffffff8108637a>] ? cpu_startup_entry+0x1ba/0x220
[23981.997838] ---[ end trace a1fdb2ba510a7ceb ]---
[23984.453445] nouveau 0000:01:00.0: timeout at drivers/gpu/drm/nouveau/nvkm/engine/gr/g84.c:169/g84_gr_tlb_flush()!
[23992.508775] nouveau 0000:01:00.0: timeout at drivers/gpu/drm/nouveau/nvkm/subdev/bar/g84.c:38/g84_bar_flush()!
[23992.508778] nouveau 0000:01:00.0: fifo: intr 04e00000
[23992.508802] nouveau 0000:01:00.0: mc: intr 0a0120e0
[23994.518276] nouveau 0000:01:00.0: timeout at drivers/gpu/drm/nouveau/nvkm/subdev/mmu/nv50.c:195/nv50_vm_flush()!
[23994.518280] nouveau 0000:01:00.0: mmu: vm flush timeout: engine 13
[23997.891927] nouveau 0000:01:00.0: gr: PGRAPH TLB flush idle timeout fail
[23997.891932] nouveau 0000:01:00.0: timeout at drivers/gpu/drm/nouveau/nvkm/subdev/bar/g84.c:38/g84_bar_flush()!
[23997.891938] nouveau 0000:01:00.0: gr: PGRAPH_STATUS 00000601 [BUSY VFETCH CCACHE_PREGEOM]
[23997.891941] nouveau 0000:01:00.0: gr: PGRAPH_VSTATUS0: 00000009 [VFETCH CCACHE]
[23997.891945] nouveau 0000:01:00.0: gr: PGRAPH_VSTATUS1: 00000000 []
[23997.891949] nouveau 0000:01:00.0: gr: PGRAPH_VSTATUS2: 00000000 []
[23999.900576] nouveau 0000:01:00.0: timeout at drivers/gpu/drm/nouveau/nvkm/engine/gr/g84.c:169/g84_gr_tlb_flush()!

As usually, lockup and reboot.
Tainted: W is from btrfs_destroy_inode, a fresh unrelated regression.