linux-kernel - [PATCH 1/3] signal: Don't always put SIGKILL in shared

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Date:   Sun, 21 May 2023 21:51:22 -0500
From:   Mike Christie <michael.christie@...cle.com>
To:     oleg@...hat.com, linux@...mhuis.info, nicolas.dichtel@...nd.com,
        axboe@...nel.dk, ebiederm@...ssion.com,
        torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, mst@...hat.com,
        sgarzare@...hat.com, jasowang@...hat.com, stefanha@...hat.com,
        brauner@...nel.org
Cc:     Mike Christie <michael.christie@...cle.com>
Subject: [PATCH 1/3] signal: Don't always put SIGKILL in shared_pending

When get_pending detects the task has been marked to be killed we try to
clean up the SIGKLL by doing a sigdelset and recalc_sigpending, but we
still leave it in shared_pending. If the signal is being short circuit
delivered there is no need to put in shared_pending so this adds a check
in complete_signal.

This patch was modified from Eric Biederman <ebiederm@...ssion.com>
original patch.

Signed-off-by: Mike Christie <michael.christie@...cle.com>
---
 kernel/signal.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/kernel/signal.c b/kernel/signal.c
index 8f6330f0e9ca..3dc99b9aec7f 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1052,6 +1052,14 @@ static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
 			signal->flags = SIGNAL_GROUP_EXIT;
 			signal->group_exit_code = sig;
 			signal->group_stop_count = 0;
+
+			/*
+			 * The signal is being short circuit delivered so
+			 * don't set pending.
+			 */
+			if (type != PIDTYPE_PID)
+				sigdelset(&signal->shared_pending.signal, sig);
+
 			t = p;
 			do {
 				task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
-- 
2.25.1