ML rebooting without notice..!

[50548]

WTH is happening here..? This is already the third time an automatic reboot happens after waking from sleep. The main error message is this, followed of course by many other details:

Spinlock acquisition timed out: lock=0xffffff80523ccd98

And these are the Console messages from the time the reboot occurred:

17/11/12 15:06:50,587 WindowServer[117]: CGXSetWindowBackgroundBlurRadius: Invalid window 0xffffffff
17/11/12 15:06:50,588 loginwindow[62]: find_shared_window: WID -1
17/11/12 15:06:50,588 loginwindow[62]: CGSGetWindowTags: Invalid window 0xffffffff
17/11/12 15:06:50,588 loginwindow[62]: find_shared_window: WID -1
17/11/12 15:06:50,588 loginwindow[62]: CGSSetWindowTags: Invalid window 0xffffffff
17/11/12 15:06:50,741 WindowServer[117]: Created shield window 0x619 for display 0x042801c0
17/11/12 15:06:50,741 WindowServer[117]: device_generate_desktop_screenshot: authw 0x7fb97ac8a4f0(2000), shield 0x7fb97c60fcd0(2001)
17/11/12 15:06:50,756 WindowServer[117]: device_generate_lock_screen_screenshot: authw 0x7fb97ac8a4f0(2000), shield 0x7fb97c60fcd0(2001)
17/11/12 15:07:41,242 mdworker[14093]: Unable to talk to lsboxd
17/11/12 15:07:41,245 mdworker[14095]: Unable to talk to lsboxd
17/11/12 15:07:41,248 mdworker[14094]: Unable to talk to lsboxd
17/11/12 15:07:41,289 sandboxd[14097]: ([14093]) mdworker(14093) deny mach-lookup com.apple.ls.boxd
17/11/12 15:07:41,293 sandboxd[14097]: ([14095]) mdworker(14095) deny mach-lookup com.apple.ls.boxd
17/11/12 15:07:41,296 sandboxd[14097]: ([14094]) mdworker(14094) deny mach-lookup com.apple.ls.boxd
17/11/12 15:07:41,000 kernel[0]: Sandbox: sandboxd(14097) deny mach-lookup com.apple.coresymbolicationd
17/11/12 15:11:41,945 mdworker[14117]: Unable to talk to lsboxd
17/11/12 15:11:41,948 mdworker[14116]: Unable to talk to lsboxd
17/11/12 15:11:41,955 mdworker[14115]: Unable to talk to lsboxd
17/11/12 15:11:41,991 sandboxd[14119]: ([14117]) mdworker(14117) deny mach-lookup com.apple.ls.boxd
17/11/12 15:11:41,994 sandboxd[14119]: ([14116]) mdworker(14116) deny mach-lookup com.apple.ls.boxd
17/11/12 15:11:41,997 sandboxd[14119]: ([14115]) mdworker(14115) deny mach-lookup com.apple.ls.boxd
17/11/12 15:11:42,000 kernel[0]: Sandbox: sandboxd(14119) deny mach-lookup com.apple.coresymbolicationd
17/11/12 15:12:14,165 com.apple.time[11]: Next maintenance wake [Backup Interval]: <date: 0x7fa8a5509c70> Sat Nov 17 16:00:16 2012 CET (approx)
17/11/12 15:12:14,165 com.apple.time[11]: Requesting maintenance wake [Backup Interval]: <date: 0x7fa8a5509c70> Sat Nov 17 16:00:16 2012 CET (approx)
17/11/12 15:12:39,000 bootlog[0]: BOOT_TIME 1353161559 0
17/11/12 15:12:40,000 kernel[0]: PMAP: PCID enabled

Can anyone help me here?