Problem:

Customer was encountering RTS 105 when executing .gnt objects in RHEL 7.0 in z/390.  Intermediate codes are getting executed without any issues.

Simulation of the issue indicate the following:

[junf@mf-zrhel72cs-01 tictac]$ cobrun tictac.gnt

Load error : file '/home/junf/projects/tictac/tictac.gnt'

error code: 105, pc=0, call=1, seg=0

105     Memory allocation error

The strace output when running the .gnt  objects indicated that mprotect encountered an EACCES error or Permission denied:

57568 00:07:05 open("/dev/zero", O_RDWR) = 6

57568 00:07:05 mmap(NULL, 4784, PROT_READ|PROT_WRITE, MAP_PRIVATE, 6, 0) = 0x3fff6dd8000

57568 00:07:05 close(6)                 = 0

57568 00:07:05 mprotect(0x3fff6dd8000, 4096, PROT_READ|PROT_WRITE|PROT_EXEC) = -1 EACCES (Permission denied)

57568 00:07:05 munmap(0x3fff6dd8000, 4784) = 0

In the customer’s environment, the same error is encountered even when using root id.

Resolution:

Customer raised the issue to their Linux Admin and found that SELinux is in Enforcing Mode.

Issue was resolved when SELinux was changed to Permissive Mode.

Related Incident: 2887373