pidns: kill the unnecessary CLONE_NEWPID in copy_process()
authorOleg Nesterov <oleg@redhat.com>
Wed, 11 Sep 2013 21:19:40 +0000 (14:19 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 11 Sep 2013 22:56:19 +0000 (15:56 -0700)
commit5167246a8ad617df55717c2d901da5e2aedffcfa
tree170259b1cad5dd2f1ff6bd46db39a2ac25aa07b4
parente79f525e99b04390ca4d2366309545a836c03bf1
pidns: kill the unnecessary CLONE_NEWPID in copy_process()

Commit 8382fcac1b81 ("pidns: Outlaw thread creation after
unshare(CLONE_NEWPID)") nacks CLONE_NEWPID if the forking process
unshared pid_ns.  This is correct but unnecessary, copy_pid_ns() does
the same check.

Remove the CLONE_NEWPID check to cleanup the code and prepare for the
next change.

Test-case:

static int child(void *arg)
{
return 0;
}

static char stack[16 * 1024];

int main(void)
{
pid_t pid;

assert(unshare(CLONE_NEWUSER | CLONE_NEWPID) == 0);

pid = clone(child, stack + sizeof(stack) / 2,
CLONE_NEWPID | SIGCHLD, NULL);
assert(pid < 0 && errno == EINVAL);

return 0;
}

clone(CLONE_NEWPID) correctly fails with or without this change.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Colin Walters <walters@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/fork.c