panic: pmap_zero_page: CMAP3 busy

On just fetched -current :

....
Mounting root from nfs:
NFS ROOT: 10.0.0.6:/
panic: pmap_zero_page: CMAP3 busy
Debugger("panic")
Stopped at      Debugger+0x53:  xchgl   %ebx,in_Debugger.0
db> tr
Debugger(0,c1b4c7a0,0,c0f4b59c,0) at Debugger+0x53
_end(c0f4b580,c0f4b584,c0f48ab0,c0f48ab8,0) at 0xc0f4b580
_end(c0f4b500,c0f4b504,c0f48980,c0f48988,0) at 0xc1b4c5ac
_end(c0f4b480,c0f4b484,c0f48850,c0f48858,0) at 0xc1b4c790
_end(c0f4b400,c0f4b404,c0f48720,c0f48728,0) at 0xc1b4c974
_end(c0f4b380,c0f4b384,c0f485f0,c0f485f8,0) at 0xc1b4cb58
_end(c0f4b300,c0f4b304,c0f484c0,c0f484c8,0) at 0xc1b4cd3c
_end(c0f4b280,c0f4b284,c0f48390,c0f48398,0) at 0xc1b68000
_end(c0f4b200,c0f4b204,c0f48260,c0f48268,0) at 0xc1b681e4
_end(c0f4b180,c0f4b184,c0f48130,c0f48138,0) at 0xc1b683c8
_end(c0f4b100,c0f4b104,c1b695f0,c1b695f8,0) at 0xc1b685ac
_end(c0f4bb00,c0f4bb04,c0f474c0,c0f474c8,0) at 0xc1b68790
_end(c0f4ba80,c0f4ba84,c0f47390,c0f47398,0) at 0xc1b68974
_end(c0f4ba00,c0f4ba04,c0f47260,c0f47268,0) at 0xc0f4d1e4
_end(c0f4b980,c0f4b984,c0f47130,c0f47138,0) at 0xc0f4d3c8
_end(c0f4b900,c0f4b904,c0f47000,c0f47008,0) at 0xc0f4d5ac
_end(c0f4b880,c0f4b884,c0f4e260,c0f4e268,0) at 0xc0f4d790
_end(c0f4b800,c0f4b804,c0f4e130,c0f4e138,0) at 0xc0f4d974
_end(c0f4b780,c0f4b784,c0f4e000,c0f4e008,0) at 0xc0f4db58
_end(c0f4b700,c0f4b704,c0f48e40,c0f48e48,0) at 0xc0f4dd3c
_end(c0f4b680,c0f4b684,c0f48d10,c0f48d18,0) at 0xc1b4c000
_end(c0f4c000,c0f4c004,c0f48000,c0f48008,0) at 0xc1b4c1e4
_end(c0f4bf00,c0f4bf04,c0f47e40,c0f47e48,0) at 0xc1b4c3c8
_end(c0f4be80,c0f4be84,c0f47d10,c0f47d18,0) at 0xc0f46000
_end(c0f4be00,c0f4be04,c0f47be0,c0f47be8,0) at 0xc0f461e4
_end(c0f4bd80,c0f4bd84,c0f47ab0,c0f47ab8,0) at 0xc0f463c8
_end(c0f4bd00,c0f4bd04,c0f47980,c0f47988,0) at 0xc0f465ac
_end(c0f4bc80,c0f4bc84,c0f47850,c0f47858,0) at 0xc0f46790
_end(c0f4bc00,c0f4bc04,c0f47720,c0f47728,0) at 0xc0f46974
_end(c0f4bb80,c0f4bb84,c0f475f0,c0f475f8,0) at 0xc0f46b58
_end(c05fbb00,c05fbb04,c05fb9c0,c05fb9c8,0) at 0xc0f46d3c
_end() at 0xc0f4d000
db> 

Two days ago was OK.

-a