On Fri, Oct 26, 2007 at 03:37:38PM -0400, Mathieu Desnoyers wrote: > > 1 - process A enters in a syscall, TIF_KERNEL_TRACE is cleared > 2 - we activate TIF_KERNEL_TRACE > 3 - process A returns from syscall (with wrong top of stack ?) -> segfault. > > Am I on the right track ?
Yes. The code was not designed to allow that. The syscall path has been optimized to go as fast as possible. > > Can this be a concern with TIF_SYSCALL_TRACE also ? (potential race in > ptrace ?) ptrace only changes state in stopped processes; and those are not hanging in syscalls. So no there is no race in a standard kernel. If you wanted to change it the right way would be probably to test for SYSCALL_TRACE too in the work flags and handle it there -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
