I am writing some software that monitors a guest VM using virtual-machine introspection and "hijacks" system calls under certain conditions. For example, the program might inject an int3/breakpoint into the guest kernel at the entry point to sys_open. When the breakpoint is hit, the program might set the guest instruction pointer to the address to which sys_open would have itself returned and set register RAX to some desired error-code return value. The problem I am encountering is that for some reason the process is triggering a "uprobe ... failed to handle uretprobe" message from the guest kernel. I do not yet know enough about uprobes to understand what might be causing this. Is there something in procedures such as sys_open which must execute to prevent the error which causes the kernel to print this message? -- Mike :wq