Comment 12 for bug 1409393

It just happened again , with 3.13.0-46-lowlatency #79 & 1:7.7+1ubuntu8.1 :

Radeon CP lockup stall dmesg :

[393791.346730] radeon 0000:01:00.0: GPU lockup CP stall for more than 10000msec
[393791.346741] radeon 0000:01:00.0: GPU lockup (waiting for 0x0000000000000004 last fence id 0x0000000000000002 on ring 5)
[393791.346748] [drm:uvd_v1_0_ib_test] *ERROR* radeon: fence wait failed (-35).
[393791.346755] [drm:radeon_ib_ring_tests] *ERROR* radeon: failed testing IB on ring 5 (-35).
[393791.908949] radeon 0000:01:00.0: GPU lockup CP stall for more than 10562msec
[393791.908961] radeon 0000:01:00.0: GPU lockup (waiting for 0x0000000000000003 last fence id 0x0000000000000002 on ring 5)

Xorg server frozen:

(gdb) where
#0 0x00007fb3b8e5a337 in ioctl () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007fb3ba1413a4 in drmIoctl () from /usr/lib/x86_64-linux-gnu/libdrm.so.2
#2 0x00007fb3ba1436bf in drmCommandWriteRead () from /usr/lib/x86_64-linux-gnu/libdrm.so.2
#3 0x00007fb3b4ca6357 in ?? () from /usr/lib/x86_64-linux-gnu/libdrm_radeon.so.1
#4 0x00007fb3b4ef5738 in ?? () from /usr/lib/xorg/modules/drivers/radeon_drv.so
#5 0x00007fb3b4ef5ba8 in ?? () from /usr/lib/xorg/modules/drivers/radeon_drv.so
#6 0x00007fb3bb2a8054 in _CallCallbacks ()
#7 0x00007fb3bb3f9dd6 in WriteToClient ()
#8 0x00007fb3bb2addf2 in WriteEventsToClient ()
#9 0x00007fb3bb37a66a in ?? ()
#10 0x00007fb3bb38013d in DamageReportDamage ()
#11 0x00007fb3bb38082a in ?? ()
#12 0x00007fb3bb383b43 in ?? ()
#13 0x00007fb3bb29f3d1 in ?? ()
#14 0x00007fb3bb2a2f0e in ?? ()
#15 0x00007fb3bb2a6d9a in ?? ()
#16 0x00007fb3b8d8aec5 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
#17 0x00007fb3bb2921ee in _start ()
(gdb) info regs
Undefined info command: "regs". Try "help info".
(gdb) info reg
rax 0xfffffffffffffe00 -512
rbx 0xffffffff 4294967295
rcx 0xffffffffffffffff -1
rdx 0x7fb3bb8135c8 140409921680840
rsi 0xc0206466 3223348326
rdi 0xc 12
rbp 0x7fb3bb8135c8 0x7fb3bb8135c8
rsp 0x7fff7cb6a060 0x7fff7cb6a060
r8 0x4030de 4206814
r9 0x5b 91
r10 0xc16 3094
r11 0x246 582
r12 0xc0206466 3223348326
r13 0xc 12
r14 0x7fb3be74ac20 140409971190816
r15 0x7fff7cb6a250 140735285731920
rip 0x7fb3ba1413a4 0x7fb3ba1413a4 <drmIoctl+52>
eflags 0x246 [ PF ZF IF ]
cs 0x33 51
ss 0x2b 43
ds 0x0 0
es 0x0 0
fs 0x0 0
gs 0x0 0