deadlock from xerror handler in steam

[zmike]

When running the latest steam beta on llvmpipe, it looks like some XError handler inside SDL is causing a deadlock by attempting to call X11_XRRGetScreenResourcesCurrent inside the handler:

#0  0x00007fb11a2ab1d9 in __futex_abstimed_wait_common () from /lib64/libc.so.6
#1  0x00007fb11a2adb79 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libc.so.6
#2  0x00007fb11a9a97b3 in _XReply (dpy=0x270629d83800, rep=0x7fb0feb00f00, extra=0, discard=0) at /usr/src/debug/libX11-1.8.4-1.fc38.x86_64/src/xcb_io.c:696
#3  0x00007fb11a9232b9 in doGetScreenResources () from /lib64/libXrandr.so.2
#4  0x00007fb11af6372e in ?? () from /home/zmike/.local/share/Steam/ubuntu12_64/libSDL3.so.0
#5  0x00007fb11af4282f in ?? () from /home/zmike/.local/share/Steam/ubuntu12_64/libSDL3.so.0
#6  0x00007fb11af67743 in ?? () from /home/zmike/.local/share/Steam/ubuntu12_64/libSDL3.so.0
#7  0x00007fb11a9a78ab in _XError (dpy=dpy@entry=0x270629d83800, rep=rep@entry=0x27062c7a6bd0) at /usr/src/debug/libX11-1.8.4-1.fc38.x86_64/src/XlibInt.c:1503
#8  0x00007fb11a9a79bf in handle_error (dpy=0x270629d83800, err=0x27062c7a6bd0, in_XReply=<optimized out>)
    at /usr/src/debug/libX11-1.8.4-1.fc38.x86_64/src/xcb_io.c:211
#9  0x00007fb11a9a7a7d in handle_response (dpy=0x270629d83800, response=0x27062c7a6bd0, in_XReply=<optimized out>)
    at /usr/src/debug/libX11-1.8.4-1.fc38.x86_64/src/xcb_io.c:403
#10 0x00007fb11a9a97cd in _XReply (dpy=dpy@entry=0x270629d83800, rep=rep@entry=0x7fb0feb01240, extra=extra@entry=0, discard=discard@entry=1)
    at /usr/src/debug/libX11-1.8.4-1.fc38.x86_64/src/xcb_io.c:722
#11 0x00007fb11a9a9b55 in XSync (dpy=0x270629d83800, discard=0) at /usr/src/debug/libX11-1.8.4-1.fc38.x86_64/src/Sync.c:44
#12 0x00007fb11a8d9dea in swrastXPutImage (draw=0x27062c4c8b80, op=3, srcx=0, srcy=0, x=0, y=0, w=1280, h=832, stride=5120, shmid=1638426, 
    data=0x7fb0cffde000 "", loaderPrivate=0x27062c46a200) at ../src/glx/drisw_glx.c:210
#13 0x00007fb11a8d9f35 in swrastPutImageShm2 (draw=0x27062c4c8b80, op=3, x=0, y=0, w=1280, h=832, stride=5120, shmid=1638426, shmaddr=0x7fb0cffde000 "", 
    offset=0, loaderPrivate=0x27062c46a200) at ../src/glx/drisw_glx.c:246
#14 0x00007fb0f08ffed1 in put_image_shm (drawable=0x27062c4c8b80, shmid=1638426, shmaddr=0x7fb0cffde000 "", offset=0, offset_x=0, x=0, y=0, width=1280, 
    height=832, stride=5120) at ../src/gallium/frontends/dri/drisw.c:88
#15 0x00007fb0f0900327 in drisw_put_image_shm (drawable=0x27062c4c8b80, shmid=1638426, shmaddr=0x7fb0cffde000 "", offset=0, offset_x=0, x=0, y=0, width=1280, 
    height=832, stride=5120) at ../src/gallium/frontends/dri/drisw.c:184
#16 0x00007fb0f1515f6d in dri_sw_displaytarget_display (ws=0x27062a271720, dt=0x27062c7a6de0, context_private=0x27062c4c8b80, box=0x0)
    at ../src/gallium/winsys/sw/dri/dri_sw_winsys.c:277
#17 0x00007fb0f154812f in llvmpipe_flush_frontbuffer (_screen=0x27062a737800, _pipe=0x27062c553000, resource=0x27062c617e00, level=0, layer=0, 
    context_private=0x27062c4c8b80, sub_box=0x0) at ../src/gallium/drivers/llvmpipe/lp_screen.c:852
#18 0x00007fb0f090039d in drisw_present_texture (pipe=0x27062c553000, drawable=0x27062c4c8b80, ptex=0x27062c617e00, sub_box=0x0)
    at ../src/gallium/frontends/dri/drisw.c:196
#19 0x00007fb0f09003fd in drisw_copy_to_front (pipe=0x27062c553000, drawable=0x27062c4c8b80, ptex=0x27062c617e00) at ../src/gallium/frontends/dri/drisw.c:212
#20 0x00007fb0f09005a2 in drisw_swap_buffers (drawable=0x27062c4c8b80) at ../src/gallium/frontends/dri/drisw.c:258
#21 0x00007fb0f08ff6af in driSwapBuffers (pdp=0x27062c4c8b80) at ../src/gallium/frontends/dri/dri_util.c:849
#22 0x00007fb11a8daf19 in driswSwapBuffers (pdraw=0x27062c46a200, target_msc=0, divisor=0, remainder=0, flush=1) at ../src/glx/drisw_glx.c:770
#23 0x00007fb11a8dcd76 in glXSwapBuffers (dpy=0x270629d83800, drawable=29360140) at ../src/glx/glxcmds.c:677
#24 0x00007fb11af668c3 in ?? () from /home/zmike/.local/share/Steam/ubuntu12_64/libSDL3.so.0
#25 0x00000000004acb75 in CCompositorGLThread::Redraw() ()
#26 0x00000000004ac938 in CCompositorGLThread::Run() ()
#27 0x00000000007a159a in SteamThreadTools::CThread::ThreadExceptionWrapper(void*) ()
#28 0x000000000079eee8 in CatchAndWriteContext_t::Invoke() ()
#29 0x000000000079eac8 in CatchAndWriteMiniDump_Impl(CatchAndWriteContext_t&) ()
#30 0x000000000079ef89 in CatchAndWriteMiniDumpForVoidPtrFn ()
#31 0x00000000007a1503 in SteamThreadTools::CThread::ThreadProc(void*) ()
#32 0x00007fb11a2ae907 in start_thread () from /lib64/libc.so.6
#33 0x00007fb11a334870 in clone3 () from /lib64/libc.so.6

X11 requests can't be made from the error handler, as this will cause a deadlock.

Mesa issue: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9345