I ran into this about a month about and it happens with the beta and normal steam client. It seems like each interaction that I do with the steam client has a chance to freeze it. It could be such a simple thing as just selecting a game in my library to moving focus back to the steam client after I were on an other workspace.

I can trigger it really fast by quickly moving my mouse over the "STORE LIBRARY COMMUNITY" back and forth so that dropdown menus are spawned and removed in a quick fashion. Then after a few seconds of doing that, the steam client will freeze for me and it will not redraw itself. The tray icon is not responding to clicks either and I have to kill it.

If it froze when a drop down menu were visible the dropdown menu is now visiable on all workspaces till I kill steam...

When it freezes it also makes Xorg max out one of my cpu cores.

I started steam with "DEBUGGER=gdb steam" and then did a "ctrl+c" when it had froze to get the following backtrace. I should note that I tried to use the bundled libxcb before and it didn't help. As you can see it also happens with my system libxcb.

Backtrace:

(gdb) bt
#0  0xf7fd9b89 in __kernel_vsyscall ()
#1  0xf7bb9d5b in poll () from /lib32/libc.so.6
#2  0xf7ac0f65 in _xcb_conn_wait () from /usr/lib32/libxcb.so.1
#3  0xf7ac31b6 in xcb_wait_for_special_event () from /usr/lib32/libxcb.so.1
#4  0xf73213b9 in dri3_find_back () from /usr/lib32/libGL.so.1
#5  0xf7322339 in loader_dri3_get_buffers () from /usr/lib32/libGL.so.1
#6  0xf6afff53 in dri2_allocate_textures () from /usr/lib32/dri/radeonsi_dri.so
#7  0xf6afcc43 in dri_st_framebuffer_validate () from /usr/lib32/dri/radeonsi_dri.so
#8  0xf6a2b8df in st_framebuffer_validate () from /usr/lib32/dri/radeonsi_dri.so
#9  0xf6a2ce00 in st_manager_validate_framebuffers () from /usr/lib32/dri/radeonsi_dri.so
[#10](/issue/ValveSoftware/steam-for-linux/10) 0xf69d9fcf in st_validate_state () from /usr/lib32/dri/radeonsi_dri.so
[#11](/issue/ValveSoftware/steam-for-linux/11) 0xf69e239e in st_Clear () from /usr/lib32/dri/radeonsi_dri.so
[#12](/issue/ValveSoftware/steam-for-linux/12) 0xf689a95c in _mesa_Clear () from /usr/lib32/dri/radeonsi_dri.so
[#13](/issue/ValveSoftware/steam-for-linux/13) 0xef692211 in ?? () from /home/zed/.local/share/Steam/ubuntu12_32/vgui2_s.so
[#14](/issue/ValveSoftware/steam-for-linux/14) 0xef694dc5 in ?? () from /home/zed/.local/share/Steam/ubuntu12_32/vgui2_s.so
[#15](/issue/ValveSoftware/steam-for-linux/15) 0xef6a4a0d in ?? () from /home/zed/.local/share/Steam/ubuntu12_32/vgui2_s.so
[#16](/issue/ValveSoftware/steam-for-linux/16) 0xf234c350 in ?? () from /home/zed/.local/share/Steam/ubuntu12_32/steamui.so
[#17](/issue/ValveSoftware/steam-for-linux/17) 0xf2364d2b in ?? () from /home/zed/.local/share/Steam/ubuntu12_32/steamui.so
[#18](/issue/ValveSoftware/steam-for-linux/18) 0xf236edc5 in ?? () from /home/zed/.local/share/Steam/ubuntu12_32/steamui.so
[#19](/issue/ValveSoftware/steam-for-linux/19) 0x5659541a in RunSteam(int, char**, bool) ()
[#20](/issue/ValveSoftware/steam-for-linux/20) 0x5657de32 in ?? ()
[#21](/issue/ValveSoftware/steam-for-linux/21) 0xf7af65e7 in __libc_start_main () from /lib32/libc.so.6
[#22](/issue/ValveSoftware/steam-for-linux/22) 0x565806d9 in _start ()

Steam system info:

Computer Information:
    Manufacturer:  Unknown
    Model:  Unknown
    Form Factor: Desktop
    No Touch Input Detected

Processor Information:
    CPU Vendor:  AuthenticAMD
    CPU Family:  0x15
    CPU Model:  0x1
    CPU Stepping:  0x2
    CPU Type:  0x0
    Speed:  4000 Mhz
    8 logical processors
    8 physical processors
    HyperThreading:  Unsupported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Supported
    SSE41:  Supported
    SSE42:  Supported
    AES:  Supported
    AVX:  Supported
    CMPXCHG16B:  Supported
    LAHF/SAHF:  Supported
    PrefetchW:  Unsupported

Network Information:
    Network Speed:  

Operating System Version:
    "NAME=Gentoo" (64 bit)
    Kernel Name:  Linux
    Kernel Version:  4.4.5-gentoo
    X Server Vendor:  The X.Org Foundation
    X Server Release:  11899001
    X Window Manager:  awesome
    Steam Runtime Version:  steam-runtime-release_2016-02-23

Video Card:
    Driver:  X.Org Gallium 0.4 on AMD HAWAII (DRM 2.43.0, LLVM 3.9.0)

    Driver Version:  3.0 Mesa 11.3.0-devel (git-1e8435c)
    OpenGL Version: 3.0
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 59 Hz
    VendorID Not Detected
    DeviceID Not Detected
    Number of Monitors:  1
    Number of Video Cards Not Detected
    Primary Display Resolution:  1920 x 1200
    Desktop Resolution: 1920 x 1200
    Primary Display Size: 20,39" x 12,76"  (24,02" diag)
                                            51,8cm x 32,4cm  (61,0cm diag)
    Primary VRAM: 4096 MB

Sound card:
    Audio device: ICE1724 - multitrack

Memory:
    RAM:  11961 Mb

Miscellaneous:
    UI Language:  English
    LANG:  sv_SE.utf8
    Microphone:  Not set
    Total Hard Disk Space Available:  1877664 Mb
    Largest Free Hard Disk Block:  1135637 Mb
    VR Headset: None detected