From:   "Eric W. Biederman" <ebiederm@xmission.com>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-api@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Alexey Gladkov <legion@kernel.org>,
        Kyle Huey <me@kylehuey.com>, Oleg Nesterov <oleg@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Al Viro <viro@ZenIV.linux.org.uk>
References: <87a6ha4zsd.fsf@email.froward.int.ebiederm.org>
        <20211213225350.27481-1-ebiederm@xmission.com>
        <9363765f-9883-75ee-70f1-a1a8e9841812@gmail.com>
        <87pmp67y4r.fsf@email.froward.int.ebiederm.org>
        <5bbb54c4-7504-cd28-5dde-4e5965496625@gmail.com>
        <87bl0m14ew.fsf@email.froward.int.ebiederm.org>
Date:   Sat, 08 Jan 2022 12:15:52 -0600
In-Reply-To: <87bl0m14ew.fsf@email.froward.int.ebiederm.org> (Eric
        W. Biederman's message of "Sat, 08 Jan 2022 12:13:59 -0600")
Message-ID: <87zgo6ytyf.fsf_-_@email.froward.int.ebiederm.org>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain
Subject: [PATCH 2/2] signal: Make coredump handling explicit in complete_signal
Precedence: bulk


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.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 kernel/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index f95a4423519d..0706c1345a71 100644
--- 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)) {
 		/*
-- 
2.29.2