linux-kernel - [PATCH 4/8] signal: During coredumps set SIGNAL_GROUP_EXIT in zap

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Date:   Mon, 13 Dec 2021 16:53:46 -0600
From:   "Eric W. Biederman" <ebiederm@...ssion.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Alexey Gladkov <legion@...nel.org>,
        Kyle Huey <me@...ehuey.com>, Oleg Nesterov <oleg@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Al Viro <viro@...IV.linux.org.uk>,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH 4/8] signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process

There are only a few places that test SIGNAL_GROUP_EXIT and
are not also already testing SIGNAL_GROUP_COREDUMP.

This will not affect the callers of signal_group_exit as zap_process
also sets group_exit_task so signal_group_exit will continue to return
true at the same times.

This does not affect wait_task_zombie as the none of the threads
wind up in EXIT_ZOMBIE state during a coredump.

This does not affect oom_kill.c:__task_will_free_mem as
sig->core_state is tested and handled before SIGNAL_GROUP_EXIT is
tested for.

Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
 fs/coredump.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/coredump.c b/fs/coredump.c
index a9c25f20118f..5e5a90de7be3 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -347,13 +347,13 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm,
 	return ispipe;
 }
 
-static int zap_process(struct task_struct *start, int exit_code, int flags)
+static int zap_process(struct task_struct *start, int exit_code)
 {
 	struct task_struct *t;
 	int nr = 0;
 
 	/* Allow SIGKILL, see prepare_signal() */
-	start->signal->flags = SIGNAL_GROUP_COREDUMP | flags;
+	start->signal->flags = SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP;
 	start->signal->group_exit_code = exit_code;
 	start->signal->group_stop_count = 0;
 
@@ -378,7 +378,7 @@ static int zap_threads(struct task_struct *tsk,
 	if (!signal_group_exit(tsk->signal)) {
 		tsk->signal->core_state = core_state;
 		tsk->signal->group_exit_task = tsk;
-		nr = zap_process(tsk, exit_code, 0);
+		nr = zap_process(tsk, exit_code);
 		clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
 		tsk->flags |= PF_DUMPCORE;
 		atomic_set(&core_state->nr_threads, nr);
-- 
2.29.2