Hi, > with the 4.9.0-rt1 and also the 4.9.4-rt2 kernel (x86, 64bit) I observe a strange issue > when running my multithreaded real time executable within gdb. > > Fairly often (in about 40% of all runs) the gdb stops executing with the message: > Thread 8 "MDL07-Acknowled" received signal SIGSTOP, Stopped (signal). > [Switching to Thread 0x7fffef141700 (LWP 9770)] > 0x00007ffff535b24d in read () at ../sysdeps/unix/syscall-template.S:84 > > Often it helps to enter "continue" a couple of times to continue the debugging. > However, sometimes it ends up in an endless loop of "continue" followed by a > SIGSTOP, "continue", etc. > If this issue occurs, the SIGSTOP is complained for all threads in the executable. > Different system calls are affected: read, select, pselect, clone (via pthread_create), > ... > Debugging is more or less impossible due to this issue. > No SIGSTOP is sent out by the application, the root cause for this signal is not clear > to me. > > When I reconfigured the kernel to use "Preemptible Kernel (Basic RT)" I do not > observer this issue. > Also with kernel 3.18.42-rt44 (Fully Preemptible) it works fine. I never see this issue > there. > > Any hints on how to solve the issue are highly appreciated. I did an additional analysis. The kernel version 4.1.37-rt43 is working fine, the kernel versions 4.4.39-rt50 and 4.8.11-rt7 show the same strange behavior as 4.9.0-rt1. Something on the way between 4.1.37-rt43 and 4.4.39-rt50 seems to cause the trouble. Regards Mathias -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
