| Summary: | CreateDRIDrawable can't fail gracefully | ||
|---|---|---|---|
| Product: | Mesa | Reporter: | nobled <nobled> |
| Component: | GLX | Assignee: | mesa-dev |
| Status: | RESOLVED MOVED | QA Contact: | |
| Severity: | normal | ||
| Priority: | medium | CC: | bugs.freedesktop |
| Version: | git | ||
| Hardware: | All | ||
| OS: | All | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
| Attachments: | small EGL program to produce BadDrawable error | ||
It looks like the same problem is also in glxcmds.c:glXCreateGLXPixmap (it returns the same xid whether or not driScreen->createDrawable() returned null) Okay, with debug symbols now the backtrace is:
#0 0x00434e18 in XCreateDrawable (base=0x811caa0, xDrawable=102760449,
drawable=102760449, modes=0x8170ff0) at drisw_glx.c:94
#1 driCreateDrawable (base=0x811caa0, xDrawable=102760449,
drawable=102760449, modes=0x8170ff0) at drisw_glx.c:377
#2 0x004356a7 in driFetchDrawable (gc=0x8167468, glxDrawable=102760449)
at dri_common.c:373
#3 0x004346f2 in drisw_bind_context (context=0x8167468, old=0x44a1c0,
draw=102760449, read=102760449) at drisw_glx.c:266
#4 0x00412c3f in MakeContextCurrent (dpy=0x81400c0, draw=102760449,
read=102760449, gc_user=0x8167468) at glxcurrent.c:263
#5 0x00412dd3 in glXMakeCurrent (dpy=0x81400c0, draw=102760449, gc=0x8167468)
at glxcurrent.c:287
#6 0x00462e8c in GLX_eglMakeCurrent (drv=0x80ec2e0, disp=0x80eb680,
dsurf=0x8164370, rsurf=0x8164370, ctx=0x816ed10) at egl_glx.c:760
#7 0x00454f8f in eglMakeCurrent (dpy=0x80eb680, draw=0x8164370,
read=0x8164370, ctx=0x816ed10) at eglapi.c:478
XGetVisualInfo() returned null, and that doesn't get checked for.
This patch by ajax back in May seems relevant, BTW. I'll test it (and Chad's patches) when I get a chance. http://lists.freedesktop.org/archives/mesa-dev/2011-May/007353.html Good news and bad news.
Good news: I tested in an Ubuntu Maverick chroot, and I can't reproduce the segfault -- maybe it was fixed in Xlib? (In Lucid, libX11 is version 1.3.2; in Maverick, it's 1.3.3) Now, instead of silently segfaulting, it seems to call exit(1) after giving a much more informative printout. Which is a *very slight* improvement:
(gdb) finish
Run till exit from #0 drisw_bind_context (context=0x80690b0, old=0x4871e0,
draw=106954753, read=106954753) at drisw_glx.c:267
X Error of failed request: BadDrawable (invalid Pixmap or Window parameter)
Major opcode of failed request: 55 (X_CreateGC)
Resource id in failed request: 0x6600001
Serial number of failed request: 26
Current serial number in output stream: 28
Program exited with code 01.
(gdb) quit
Bad news is, ajax's patch no longer applies cleanly to master <773556e0f537eba82d9d68d618e229140f413620>, and I tested both of Chad's patches and the bug still happens.
I'll attach a reduced testcase.
Created attachment 48483 [details]
small EGL program to produce BadDrawable error
(Unrelatedly, I had to workaround another bug in the egl_glx driver by commenting out the EGL_RENDERABLE_TYPE line: otherwise, it failed to create the EGLSurface at all because it didn't recognize it: "libEGL warning: bad surface attribute 0x3040")
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(I'm running on Ubuntu 10.04 x86-32 with mesa from the 7.10 Natty package, just for the record - but this bug is also in git and older versions.) In src/glx/glx_pbuffer.c, CreateDRIDrawable can fail, in which case it prints "failed to create drawable", but the caller has no way of knowing that it failed at all and just keeps going. Whenever I called eglCreatePbuffer, "failed to create drawable" gets printed (not sure why - because Ubuntu 10.04 has a slightly older X server?), but I got a seemingly valid EGLSurface anyway. And when I tried to use it in eglMakeCurrent(), I get a mysterious segfault: Breakpoint 4, GLX_eglMakeCurrent (drv=0x80ec2e0, disp=0x80eb680, dsurf=0x8164370, rsurf=0x8164370, ctx=0x816ed10) at egl_glx.c:738 (gdb) next (...) 760 ret = GLX_drv->glXMakeCurrent(GLX_dpy->dpy, ddraw, cctx); (gdb) next Program received signal SIGSEGV, Segmentation fault. 0x00434e18 in ?? () from /usr/lib/mesa/libGL.so.1 (gdb) bt #0 0x00434e18 in ?? () from /usr/lib/mesa/libGL.so.1 #1 0x004356a7 in ?? () from /usr/lib/mesa/libGL.so.1 #2 0x004346f2 in ?? () from /usr/lib/mesa/libGL.so.1 #3 0x00412c3f in glXMakeCurrentReadSGI () from /usr/lib/mesa/libGL.so.1 #4 0x00412dd3 in glXMakeCurrent () from /usr/lib/mesa/libGL.so.1 #5 0x00462e8c in GLX_eglMakeCurrent (drv=0x80ec2e0, disp=0x80eb680, dsurf=0x8164370, rsurf=0x8164370, ctx=0x816ed10) at egl_glx.c:760 #6 0x00454f8f in eglMakeCurrent (dpy=0x80eb680, draw=0x8164370, read=0x8164370, ctx=0x816ed10) at eglapi.c:478