Hi Sebastian, > > On 2017-01-24 09:15:59 [+0000], Koehrer Mathias (ETAS/ESW5) wrote: > > 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 also tried to generate an easy useable test case - without success so far. The issue occurs with our (large) application. Some observations I have made: - Whenever the issue occurs, at least one thread was in the system call "clone" - either called by pthread_create() or by system(). I got this information by calling "info thr" inside gdb. - I removed the calls to pthread_setschedparam() to avoid running the threads in SCHED_FIFO scheduling. Even there I got the issue. It seems not to be related to threads running in real time priority. My tooling (Debian testing/stretch): gdb 7.12 gcc 6.2.1 Regards Mathias ��.n��������+%������w��{.n�����{�����ǫ���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f