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I've been using SDL 2 on a project for a while now and I often run it under valgrind.  I've long since discounted the memory lost errors but today I noticed these new "conditional jump depends on uninitialized values" errors.


I tested it on 2.0.3 and the latest code.  Maybe it's been there longer and I just haven't run valgrind with -v in a while.  It looks like they happen at the very beginning and my program has a lot of output so I usually just see the summary at the end.



Linux robert-desktop 3.11.0-17-generic #31-Ubuntu SMP Mon Feb 3 21:52:43 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux



My SDL window code is:
SDL_Window* window = SDL_CreateWindow("swrenderer", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, WIDTH, HEIGHT, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);





Anyway, just fyi.   Hopefully someone hasn't already reported this.






==14591== HEAP SUMMARY:
==14591==     in use at exit: 90,067 bytes in 570 blocks
==14591==   total heap usage: 63,694 allocs, 63,124 frees, 26,531,161 bytes allocated
==14591== 
==14591== Searching for pointers to 570 not-freed blocks
==14591== Checked 9,233,096 bytes
==14591== 
==14591== 22 bytes in 2 blocks are definitely lost in loss record 10 of 135
==14591==    at 0x4C2A2DB: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==14591==    by 0x5A028C1: strdup (strdup.c:42)
==14591==    by 0x6FD0F86: ??? (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FD1D94: _XimSetICValueData (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FCD439: _XimLocalCreateIC (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FB39A4: XCreateIC (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x4F13A4A: SetupWindowData (SDL_x11window.c:240)
==14591==    by 0x4F13E86: X11_CreateWindow (SDL_x11window.c:553)
==14591==    by 0x4F02E2B: SDL_CreateWindow_REAL (SDL_video.c:1289)
==14591==    by 0x4F02AAF: SDL_VideoInit_REAL (SDL_video.c:189)
==14591==    by 0x4E4681E: SDL_Init_REAL (SDL.c:173)
==14591==    by 0x413F11: setup_context() (main.cpp:309)
==14591== 
==14591== 22 bytes in 2 blocks are definitely lost in loss record 11 of 135
==14591==    at 0x4C2A2DB: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==14591==    by 0x5A028C1: strdup (strdup.c:42)
==14591==    by 0x6FD0F86: ??? (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FD1D94: _XimSetICValueData (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FCD439: _XimLocalCreateIC (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FB39A4: XCreateIC (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x4F13A4A: SetupWindowData (SDL_x11window.c:240)
==14591==    by 0x4F13E86: X11_CreateWindow (SDL_x11window.c:553)
==14591==    by 0x4F02E2B: SDL_CreateWindow_REAL (SDL_video.c:1289)
==14591==    by 0x413FAF: setup_context() (main.cpp:318)
==14591==    by 0x412F41: main (main.cpp:120)
==14591== 
==14591== 22 bytes in 2 blocks are definitely lost in loss record 12 of 135
==14591==    at 0x4C2A2DB: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==14591==    by 0x5A028C1: strdup (strdup.c:42)
==14591==    by 0x6FD0F86: ??? (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FD1D94: _XimSetICValueData (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FCD439: _XimLocalCreateIC (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x6FB39A4: XCreateIC (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x4F13A4A: SetupWindowData (SDL_x11window.c:240)
==14591==    by 0x4F13E86: X11_CreateWindow (SDL_x11window.c:553)
==14591==    by 0x4EFEC3C: SDL_RecreateWindow (SDL_video.c:1388)
==14591==    by 0x4E97A73: GL_CreateRenderer (SDL_render_gl.c:404)
==14591==    by 0x4E8EE7D: SDL_CreateRenderer_REAL (SDL_render.c:269)
==14591==    by 0x4EFF3D2: SDL_CreateWindowTexture (SDL_video.c:257)
==14591== 
==14591== 66 bytes in 2 blocks are definitely lost in loss record 82 of 135
==14591==    at 0x4C2A2DB: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==14591==    by 0x6F8E4F0: XGetWindowProperty (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==14591==    by 0x4F0AC67: X11_DispatchEvent (SDL_x11events.c:572)
==14591==    by 0x4F0B737: X11_PumpEvents (SDL_x11events.c:1017)
==14591==    by 0x4E7F518: SDL_PollEvent_REAL (SDL_events.c:402)
==14591==    by 0x4140E4: handle_events() (main.cpp:356)
==14591==    by 0x413BE3: main (main.cpp:248)
==14591== 
==14591== 79 bytes in 1 blocks are definitely lost in loss record 85 of 135
==14591==    at 0x4C2A2DB: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==14591==    by 0x8BFF4EC: ??? (in /usr/lib/nvidia-304/libGL.so.304.8
==14591==    by 0x6F722F656D6F682E: ???
==14591==    by 0x6F72702F74726561: ???
==14591==    by 0x676E696D6D617266: ???
==14591==    by 0x65704F2F2B2B432E: ???
==14591==    by 0x5F77656E2F4C476D: ???
==14591==    by 0x737463656A6F726F: ???
==14591==    by 0x6E65727773796D2E: ???
==14591==    by 0x75622F7265726563: ???
==14591==    by 0x657277732F646C68: ???
==14591==    by 0x72657265646D: ???
==14591== 
==14591== LEAK SUMMARY:
==14591==    definitely lost: 211 bytes in 9 blocks
==14591==    indirectly lost: 0 bytes in 0 blocks
==14591==      possibly lost: 0 bytes in 0 blocks
==14591==    still reachable: 89,856 bytes in 561 blocks
==14591==         suppressed: 0 bytes in 0 blocks
==14591== Reachable blocks (those to which a pointer was found) are not shown.
==14591== To see them, rerun with: --leak-check=full --show-reachable=yes
==14591== 
==14591== ERROR SUMMARY: 9 errors from 9 contexts (suppressed: 10 from 3)
==14591== 
==14591== 1 errors in context 1 of 9:
==14591== Conditional jump or move depends on uninitialised value(s)
==14591==    at 0xA5F5B58: ??? (in /usr/lib/nvidia-304/libnvidia-glcore.so.304.8
==14591==  Uninitialised value was created by a stack allocation
==14591==    at 0x4E964B0: GL_UpdateViewport (SDL_render_gl.c:934)
==14591== 
==14591== 
==14591== 1 errors in context 2 of 9:
==14591== Conditional jump or move depends on uninitialised value(s)
==14591==    at 0xA5F5AB6: ??? (in /usr/lib/nvidia-304/libnvidia-glcore.so.304.8
==14591==  Uninitialised value was created by a stack allocation
==14591==    at 0x4E964B0: GL_UpdateViewport (SDL_render_gl.c:934)
==14591== 
==14591== 
==14591== 1 errors in context 3 of 9:
==14591== Conditional jump or move depends on uninitialised value(s)
==14591==    at 0xA5F5AAD: ??? (in /usr/lib/nvidia-304/libnvidia-glcore.so.304.8
==14591==  Uninitialised value was created by a stack allocation
==14591==    at 0x4E964B0: GL_UpdateViewport (SDL_render_gl.c:934)
==14591== 
==14591== 
==14591== 1 errors in context 4 of 9:
==14591== Conditional jump or move depends on uninitialised value(s)
==14591==    at 0xA24327A: ??? (in /usr/lib/nvidia-304/libnvidia-glcore.so.304.8
==14591==    by 0xA24377F: ??? (in /usr/lib/nvidia-304/libnvidia-glcore.so.304.8
==14591==    by 0xBF65FFF: ???
==14591==  Uninitialised value was created by a stack allocation
==14591==    at 0x4E964B0: GL_UpdateViewport (SDL_render_gl.c:934)
==14591== 
--14591-- 
--14591-- used_suppression:      8 X on SUSE11 writev uninit padding
--14591-- used_suppression:      2 dl-hack3-cond-1
==14591== 
==14591== ERROR SUMMARY: 9 errors from 9 contexts (suppressed: 10 from 3)




--
Rob

robertwinkler.com

Can I see the program that triggers this, so I can reproduce it here?

Thanks,
--ryan.


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I’m almost positive the “conditional jump depends on uninitialized values" issues are false-positives within the Nvidia OpenGL library, but I don’t have a Linux dev environment set up to verify it. I seem to remember this being an issue, though, and a quick google search confirms that it used to be an issue.

-Luke

On Mar 31, 2014, at 6:28 PM, Robert Winkler wrote: