| Summary: | Simply linking against libOpenCL.so tries accessing the GPU | ||
|---|---|---|---|
| Product: | Mesa | Reporter: | Niklas Haas <bugs.freedesktop> |
| Component: | Mesa core | Assignee: | mesa-dev |
| Status: | RESOLVED MOVED | QA Contact: | mesa-dev |
| Severity: | normal | ||
| Priority: | medium | ||
| Version: | git | ||
| Hardware: | Other | ||
| OS: | All | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
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$ echo 'int main() {}' > test.c && gcc -o test test.c -lOpenCL && strace -e open ./test open("/dev/dri", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4 open("/dev/dri", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4 open("/dev/dri", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4 open("/dev/dri", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4 open("/sys/dev/char/226:128/device/drm", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 4 open("/sys/dev/char/226:128/device/drm", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5 open("/dev/dri", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5 open("/etc/nsswitch.conf", O_RDONLY|O_CLOEXEC) = 5 open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 5 open("/sys/devices/system/cpu/online", O_RDONLY|O_CLOEXEC) = 5 open("/sys/dev/char/226:128/device/drm", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5 open("/sys/dev/char/226:128/device/drm", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5 open("/sys/dev/char/226:128/device/drm", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 5 +++ exited with 0 +++ This behavior surprises me because e.g. libGL.so does not have the same sort of behavior, and neither do libvulkan.so or other third party implementations of OpenGL/OpenCL. Merely *linking* to a library should not cause any runtime GPU access. Normally I'd expect this kind of loading logic to happen when the CL device itself is initialized, similar to how OpenGL's GPU-specific drivers only get initialized when calling `glXCreateContext` and ditto for vkCreateInstance / vkCreateDevice. Context: https://bugs.gentoo.org/show_bug.cgi?id=656086 Since this behavior surprises me, I'm also filing a bug here, even though the issue is technically downstream. Maybe we could get some elaboration.