Hi all,

I'm using Xenomai 3.2.2 at commit ec804ffbd, kernel 5.4.228, cobalt 
mode, on a Atom x5-E8000 x86-64.

Since I trarted to use the commit in message, I have a subtle segfault 
when I close my application.

I managed to reduce the case in the simple code attached to the message.
If you run the script, almost always the 
xeno-test-session-segfault-mainproc generates a segfault at exit.

Analyzing the core, the involved code is always the same:

#0  0x00007ff729498400 in __hash_key () from /usr/lib/libcobalt.so.2
#1  0x00007ff729498897 in hash_remove () from /usr/lib/libcobalt.so.2
#2  0x00007ff7294b49ac in syncluster_delobj () from 
/usr/lib/libcopperplate.so.0
#3  0x00007ff7294ce06d in ?? () from /usr/lib/libalchemy.so.0
#4  0x00007ff7294b6774 in semobj_destroy () from 
/usr/lib/libcopperplate.so.0
#5  0x00007ff7294ce216 in rt_sem_delete () from /usr/lib/libalchemy.so.0
#6  0x0000559ca0298651 in SubDummyFn (arg=<optimized out>) at main_proc.c:55
#7  0x00007ff7294cca0a in ?? () from /usr/lib/libalchemy.so.0
#8  0x00007ff7294b5ce9 in ?? () from /usr/lib/libcopperplate.so.0
#9  0x00007ff729494f7e in ?? () from /usr/lib/libcobalt.so.2
#10 0x00007ff729461ea4 in start_thread (arg=<optimized out>) at 
pthread_create.c:477
#11 0x00007ff72937859f in clone () at 
../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Reverting the commit in object the segfault disappears.

Applying the commit to 3.1 branch results in the same problem.

Seems to be a corruption of the session memory shared between processes 
caused by the atexit() callback introduced by the commit.

Some notes:
- seems that it depends on when the xeno-test-session-segfault-secproc 
exits: if exit happens during the SubDummy tasks start, the segfault is 
generated, otherwise no
- seems to be related with the number of calls of the 
xeno-test-session-segfault-secproc: with only one call (change i == 2 
with i == 1 at main_proc.c:139 and remove one call in the script), the 
problem does not happen

Thanks in advance, regards.

-- 
Mauro S.