Comment 2 for bug 1989964

[335842.604] (WW) glamor: Failed to allocate 128x88 FBO due to GL_OUT_OF_MEMORY.
[335842.604] (WW) glamor: Expect reduced performance.
[335844.555] (EE) glamor0: GL error: GL_OUT_OF_MEMORY in glMapBuffer(map failed)

followed by

[335844.561] (EE) glamor0: GL error: GL_INVALID_OPERATION in glUnmapBuffer(buffer is not mapped)

It looks like a failed allocation is not detected, and an illegal unmap follows.

From a distant it looks like an application is exhausting the Xserver memory, en the Xserver is not robust enough to report these problems to the application program and stay unaffected.

When it is followed by a segmentation error later it sure looks like memory corruption, due to not detecting the failure return from glMapBuffer.