On 04/16, Frederic Weisbecker wrote: > > On Sun, Mar 10, 2013 at 07:41:06PM +0100, Jiri Olsa wrote: > > Adding RF EFLAGS bit to be restored on return from signal from > > the original register context before the signal was entered. > > > > This will prevent the RF flag to disappear when returning > > from exception due to the signal handler being executed. > > So that happens if, say, we get a breakpoint exception and then we > run a signal handler before returning to the ip that triggered the > breakpoint?
Afaics these changes (1 and 2) should fix the bug. Suppose that the first insn in the signal handler should trigger another bp, we should clear X86_EFLAGS_RF (2/6). Otoh, we should restore it when we return to the original insn which triggered the trap to avoid another trap. But. it seems that we have yet another problem? Suppose that the signal handler does siglongjmp() and jumps to yet another insn which should trigger the trap? Oleg. -- 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/
