[PATCH 09/10] signal: Use SEND_SIG_PRIV not SEND_SIG_FORCED with SIGKILL and SIGSTOP

From: Eric W. Biederman
Date: Mon Sep 03 2018 - 16:46:03 EST


Now that siginfo is never allocated for SIGKILL and SIGSTOP there is
no difference between SEND_SIG_PRIV and SEND_SIG_FORCED for SIGKILL
and SIGSTOP. This makes SEND_SIG_FORCED unnecessary and redundant in
the presence of SIGKILL and SIGSTOP. Therefore change users of
SEND_SIG_FORCED that are sending SIGKILL or SIGSTOP to use
SEND_SIG_PRIV instead.

This removes the last users of SEND_SIG_FORCED.

Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
kernel/pid_namespace.c | 2 +-
kernel/ptrace.c | 4 ++--
mm/oom_kill.c | 4 ++--
3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 2a2ac53d8b8b..c8d53397bbdd 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -216,7 +216,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
idr_for_each_entry_continue(&pid_ns->idr, pid, nr) {
task = pid_task(pid, PIDTYPE_PID);
if (task && !__fatal_signal_pending(task))
- send_sig_info(SIGKILL, SEND_SIG_FORCED, task);
+ send_sig_info(SIGKILL, SEND_SIG_PRIV, task);
}
read_unlock(&tasklist_lock);
rcu_read_unlock();
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 21fec73d45d4..45f77a1b9c97 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -396,7 +396,7 @@ static int ptrace_attach(struct task_struct *task, long request,

/* SEIZE doesn't trap tracee on attach */
if (!seize)
- send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
+ send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);

spin_lock(&task->sighand->siglock);

@@ -563,7 +563,7 @@ void exit_ptrace(struct task_struct *tracer, struct list_head *dead)

list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
if (unlikely(p->ptrace & PT_EXITKILL))
- send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
+ send_sig_info(SIGKILL, SEND_SIG_PRIV, p);

if (__ptrace_detach(tracer, p))
list_add(&p->ptrace_entry, dead);
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index b5b25e4dcbbb..3bcfeaaeed87 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -858,7 +858,7 @@ static void __oom_kill_process(struct task_struct *victim)
* in order to prevent the OOM victim from depleting the memory
* reserves from the user space under its control.
*/
- do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, PIDTYPE_TGID);
+ do_send_sig_info(SIGKILL, SEND_SIG_PRIV, victim, PIDTYPE_TGID);
mark_oom_victim(victim);
pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
@@ -896,7 +896,7 @@ static void __oom_kill_process(struct task_struct *victim)
*/
if (unlikely(p->flags & PF_KTHREAD))
continue;
- do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, PIDTYPE_TGID);
+ do_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_TGID);
}
rcu_read_unlock();

--
2.17.1