This completes the new infrastructure patch, and replaces the
cred_guard_mutex with an exec_guard_mutex, and a boolean, that
is set, when a dead-lock situation is detected.

I also change ptrace_traceme to use the new mutex, but I consider
it a bug, that it didn't take any mutex previously since it calls
security_ptrace_traceme, and all the security modules operate under
the assumption that execve is not operating in parallel.

This patch fixes the test case tools/testing/selftests/ptrace/vmaccess:

[==========] Running 2 tests from 1 test cases.
[ RUN      ] global.vmaccess
[       OK ] global.vmaccess
[ RUN      ] global.attach
[       OK ] global.attach  <= this was still failing
[==========] 2 / 2 tests passed.
[  PASSED  ]

Yes, it is an API change, but only in some very special case,
so I would exepect this to be un-noticeable to user space applications.

Bernd Edlinger (2):
  exec: Fix dead-lock in de_thread with ptrace_attach
  doc: Update documentation of ->exec_*_mutex

 Documentation/security/credentials.rst | 29 +++++++++++++++-------
 fs/exec.c                              | 44 +++++++++++++++++++++++++++-------
 fs/proc/base.c                         | 13 ++++++----
 include/linux/sched/signal.h           | 14 +++++++----
 init/init_task.c                       |  2 +-
 kernel/cred.c                          |  2 +-
 kernel/fork.c                          |  2 +-
 kernel/ptrace.c                        | 20 +++++++++++++---
 kernel/seccomp.c                       | 15 +++++++-----
 9 files changed, 102 insertions(+), 39 deletions(-)

-- 
1.9.1