Confirmed. For Panda 4460, observed dead lock on pre-built image:

http://releases.linaro.org/12.08/ubuntu/leb-panda/lt-panda-x11-base_20120826-270-ubuntu-desktop.img.gz

However, this wouldn't hang the board.

[   21.546112] =============================================
[   21.551818] [ INFO: possible recursive locking detected ]
[   21.557525] 3.4.0-2-linaro-lt-omap #2~ci+120825182553-Ubuntu Tainted: G         C O
[   21.565612] ---------------------------------------------
[   21.571258] Xorg/2058 is trying to acquire lock:
[   21.576110]  (psPVRSRVMutex){+.+.+.}, at: [<bf9ea3ff>] LinuxLockMutex+0xe/0x10 [omapdrm_pvr]
[   21.585021] 
[   21.585021] but task is already holding lock:
[   21.591156]  (psPVRSRVMutex){+.+.+.}, at: [<bf9ea3ff>] LinuxLockMutex+0xe/0x10 [omapdrm_pvr]
[   21.600036] 
[   21.600036] other info that might help us debug this:
[   21.606903]  Possible unsafe locking scenario:
[   21.606903] 
[   21.613128]        CPU0
[   21.615692]        ----
[   21.618225]   lock(psPVRSRVMutex);
[   21.621826]   lock(psPVRSRVMutex);
[   21.625396] 
[   21.625396]  *** DEADLOCK ***
[   21.625396] 
[   21.631622]  May be due to missing lock nesting notation
[   21.631622] 
[   21.638732] 2 locks held by Xorg/2058:
[   21.642669]  #0:  (drm_global_mutex){+.+.+.}, at: [<c02a9e21>] drm_release+0x21/0x288
[   21.650909]  #1:  (psPVRSRVMutex){+.+.+.}, at: [<bf9ea3ff>] LinuxLockMutex+0xe/0x10 [omapdrm_pvr]
[   21.660278] 
[   21.660278] stack backtrace:
[   21.664886] [<c0011011>] (unwind_backtrace+0x1/0x90) from [<c005b3bd>] (print_deadlock_bug+0x81/0xac)
[   21.674560] [<c005b3bd>] (print_deadlock_bug+0x81/0xac) from [<c005c409>] (validate_chain.isra.26+0x341/0x360)
[   21.685058] [<c005c409>] (validate_chain.isra.26+0x341/0x360) from [<c005cd2f>] (__lock_acquire+0x4d5/0x54e)
[   21.695373] [<c005cd2f>] (__lock_acquire+0x4d5/0x54e) from [<c005d19f>] (lock_acquire+0xbb/0xd8)
[   21.704620] [<c005d19f>] (lock_acquire+0xbb/0xd8) from [<c046804f>] (mutex_lock_nested+0x37/0x250)
[   21.714050] [<c046804f>] (mutex_lock_nested+0x37/0x250) from [<bf9ea3ff>] (LinuxLockMutex+0xe/0x10 [omapdrm_pvr])
[   21.724853] [<bf9ea3ff>] (LinuxLockMutex+0xe/0x10 [omapdrm_pvr]) from [<bf9e8ec9>] (LinuxMMapPerProcessDisconnect+0x16/0x4e [omapdrm_pvr])
[   21.737915] [<bf9e8ec9>] (LinuxMMapPerProcessDisconnect+0x16/0x4e [omapdrm_pvr]) from [<bf9ea6f3>] (OSPerProcessPrivateDataDeInit+0x10/0x26 [omapdrm_pvr])
[   21.752441] [<bf9ea6f3>] (OSPerProcessPrivateDataDeInit+0x10/0x26 [omapdrm_pvr]) from [<bf9eeff3>] (PVRSRVDissociateMemFromResmanKM+0x58/0x76 [omapdrm_pvr])
[   21.767181] [<bf9eeff3>] (PVRSRVDissociateMemFromResmanKM+0x58/0x76 [omapdrm_pvr]) from [<bf9ef113>] (PVRSRVPerProcessDataDisconnect+0x2a/0x3c [omapdrm_pvr])
[   21.781982] [<bf9ef113>] (PVRSRVPerProcessDataDisconnect+0x2a/0x3c [omapdrm_pvr]) from [<bf9f021f>] (PVRSRVProcessDisconnect+0xc/0xe [omapdrm_pvr])
[   21.795867] [<bf9f021f>] (PVRSRVProcessDisconnect+0xc/0xe [omapdrm_pvr]) from [<bf9e9195>] (PVRSRVRelease+0x5c/0x8c [omapdrm_pvr])
[   21.808227] [<bf9e9195>] (PVRSRVRelease+0x5c/0x8c [omapdrm_pvr]) from [<bf9f901f>] (PVRSRVDrmRelease+0x1a/0x2c [omapdrm_pvr])
[   21.820098] [<bf9f901f>] (PVRSRVDrmRelease+0x1a/0x2c [omapdrm_pvr]) from [<c0365c4f>] (dev_preclose+0x2b/0x54)
[   21.830627] [<c0365c4f>] (dev_preclose+0x2b/0x54) from [<c02a9e41>] (drm_release+0x41/0x288)
[   21.839477] [<c02a9e41>] (drm_release+0x41/0x288) from [<c00bd477>] (__fput+0x97/0x154)
[   21.847900] [<c00bd477>] (__fput+0x97/0x154) from [<c00bada5>] (filp_close+0x41/0x48)
[   21.856109] [<c00bada5>] (filp_close+0x41/0x48) from [<c00bae33>] (sys_close+0x87/0xc4)
[   21.864532] [<c00bae33>] (sys_close+0x87/0xc4) from [<c000c101>] (ret_fast_syscall+0x1/0x52)