Hi Sebastian, > > > 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. > > > > can you check if one of the earlier v4.4-RT releases (maybe start with > > -rt2 or -rt1) also shows this behaviour? > > If not, would you have a testcase? > I tested with 4.4.0-rt2. > Here this issue occurs very rarely. I ran the gdb for about 30 times, and here I got > one hit. > With the other kernel versions I got the issue in 20-40% of the cases. > > I will try out the other 4.4.0 releases... I ran more tests. The kernel 4.4.1-rt4 is working fairly fine (only about one hit every 30 runs) but the kernel 4.4.1-rt5 is causing the issue very often. Here is a typical output of the gdb command "info thr" for kernel 4.4.1-rt5 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". [New Thread 0x7ffff3e03700 (LWP 13240)] [New Thread 0x7ffff3602700 (LWP 13241)] [New Thread 0x7ffff0933700 (LWP 13266)] [New Thread 0x7ffff0132700 (LWP 13267)] [New Thread 0x7fffef931700 (LWP 13268)] [New Thread 0x7fffef130700 (LWP 13269)] [New Thread 0x7fffee92f700 (LWP 13270)] [New Thread 0x7fffee12e700 (LWP 13271)] Thread 5 "RTPC.bin" received signal SIGSTOP, Stopped (signal). [Switching to Thread 0x7ffff0132700 (LWP 13267)] 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 84 ../sysdeps/unix/syscall-template.S: No such file or directory. (gdb) info thr Id Target Id Frame 1 Thread 0x7ffff7fd8500 (LWP 13220) "RTPC.bin" clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:80 2 Thread 0x7ffff3e03700 (LWP 13240) "RTPC.bin" 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 3 Thread 0x7ffff3602700 (LWP 13241) "RTPC.bin" 0x00007ffff4d902b3 in select () at ../sysdeps/unix/syscall-template.S:84 4 Thread 0x7ffff0933700 (LWP 13266) "RTPC.bin" 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 * 5 Thread 0x7ffff0132700 (LWP 13267) "RTPC.bin" 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 6 Thread 0x7fffef931700 (LWP 13268) "RTPC.bin" 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 7 Thread 0x7fffef130700 (LWP 13269) "RTPC.bin" 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 8 Thread 0x7fffee92f700 (LWP 13270) "RTPC.bin" 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 9 Thread 0x7fffee12e700 (LWP 13271) "RTPC.bin" 0x00007ffff536124d in read () at ../sysdeps/unix/syscall-template.S:84 (gdb) Regards Mathias ��.n��������+%������w��{.n�����{�����ǫ���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f