What is __kernel_vsyscall?

Question

I got a core that looks very different from the ones I usually get - most of the threads are in __kernel_vsyscall() :

  9 process 11334  0xffffe410 in __kern         


        

Answer 1

__kernel_vsyscal is the method used by linux-gate.so (a part of the Linux kernel) to make a system call using the fastest available method, preferably the sysenter instruction. The thing is properly explained by Johan Petersson.