Setting a hardware breakpoint at the rex64 sysret
instruction at the end of int_ret_from_sys_call causes the system to triple fault and reboot when the breakpoint is triggered. Appears to be related the same problem as the lockup. This function can be stepped over and traced through with the TRAP FLAG set so long as a hardware breakpoint is set somewhere in the function. Otherwise upon exist the system hard hangs. If you break exactly on that instruction -- reboot. If you break a few instructions before it and single step through the call it works. If you step through the call with no breakpoint the system hard hangs. Same behavior as when you try to step from inside an nmi handler. Looks related. Caused somewhere in the way exception handlers are coded for sure. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/