signal: Make coredump handling explicit in complete_signal

Ever since commit 6cd8f0acae34 ("coredump: ensure that SIGKILL always
kills the dumping thread") it has been possible for a SIGKILL received
during a coredump to set SIGNAL_GROUP_EXIT and trigger a process
shutdown (for a second time).

Update the logic to explicitly allow coredumps so that coredumps can
set SIGNAL_GROUP_EXIT and shutdown like an ordinary process.

Link: https://lkml.kernel.org/r/87zgo6ytyf.fsf_-_@email.froward.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

diff --git a/kernel/signal.c b/kernel/signal.c
index f95a442..0706c13 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1032,7 +1032,7 @@ static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
         * then start taking the whole group down immediately.
         */
        if (sig_fatal(p, sig) &&
-           !(signal->flags & SIGNAL_GROUP_EXIT) &&
+           (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) &&
            !sigismember(&t->real_blocked, sig) &&
            (sig == SIGKILL || !p->ptrace)) {
                /*