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-rw-r--r--include/linux/sched.h2
-rw-r--r--init/main.c2
-rw-r--r--kernel/signal.c9
3 files changed, 10 insertions, 3 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0917b3df12d5..fe970cdca83c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -561,6 +561,8 @@ struct signal_struct {
#define SIGNAL_CLD_CONTINUED 0x00000020
#define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
+#define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */
+
/* If true, all threads except ->group_exit_task have pending SIGKILL */
static inline int signal_group_exit(const struct signal_struct *sig)
{
diff --git a/init/main.c b/init/main.c
index 624266b524d4..1f4406477f83 100644
--- a/init/main.c
+++ b/init/main.c
@@ -802,6 +802,8 @@ static int noinline init_post(void)
(void) sys_dup(0);
(void) sys_dup(0);
+ current->signal->flags |= SIGNAL_UNKILLABLE;
+
if (ramdisk_execute_command) {
run_init_process(ramdisk_execute_command);
printk(KERN_WARNING "Failed to execute %s\n",
diff --git a/kernel/signal.c b/kernel/signal.c
index 02ef3548aeb0..646a8765696a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -728,7 +728,8 @@ static void complete_signal(int sig, struct task_struct *p, int group)
* Found a killable thread. If the signal will be fatal,
* then start taking the whole group down immediately.
*/
- if (sig_fatal(p, sig) && !(signal->flags & SIGNAL_GROUP_EXIT) &&
+ if (sig_fatal(p, sig) &&
+ !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
!sigismember(&t->real_blocked, sig) &&
(sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
/*
@@ -1615,7 +1616,8 @@ static int do_signal_stop(int signr)
} else {
struct task_struct *t;
- if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
+ if (unlikely((sig->flags & (SIGNAL_STOP_DEQUEUED | SIGNAL_UNKILLABLE))
+ != SIGNAL_STOP_DEQUEUED) ||
unlikely(signal_group_exit(sig)))
return 0;
/*
@@ -1761,7 +1763,8 @@ relock:
/*
* Global init gets no signals it doesn't want.
*/
- if (is_global_init(current))
+ if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
+ !signal_group_exit(signal))
continue;
if (sig_kernel_stop(signr)) {