r_init+0x57/0x77 [] init+0x146/0x2fd [] kernel_thread_helper+0x7/0x10 a quick look at cpu_idle_wait() shows how broken that code is on i386: it changes the init task's affinity map but never restores it ... and because all userspace tasks get forked by init, they all inherited that single-CPU affinity mask. x86_64 cloned this bug too. Signed-off-by: Ingo Molnar Cc: Andreas Friedrich Cc: Wolfgang Erig Cc: Andrew Morton Cc: Adrian Bunk Signed-off-by: Linus Torvalds /