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-rw-r--r--kernel/signal.c66
1 files changed, 62 insertions, 4 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index cd83cc376767..62f9aea4a15a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -43,6 +43,7 @@
#include <linux/compiler.h>
#include <linux/posix-timers.h>
#include <linux/livepatch.h>
+#include <linux/cgroup.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
@@ -146,9 +147,10 @@ static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
static bool recalc_sigpending_tsk(struct task_struct *t)
{
- if ((t->jobctl & JOBCTL_PENDING_MASK) ||
+ if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
PENDING(&t->pending, &t->blocked) ||
- PENDING(&t->signal->shared_pending, &t->blocked)) {
+ PENDING(&t->signal->shared_pending, &t->blocked) ||
+ cgroup_task_frozen(t)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
return true;
}
@@ -2108,6 +2110,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
preempt_disable();
read_unlock(&tasklist_lock);
preempt_enable_no_resched();
+ cgroup_enter_frozen();
freezable_schedule();
} else {
/*
@@ -2286,6 +2289,7 @@ static bool do_signal_stop(int signr)
}
/* Now we don't run again until woken by SIGCONT or SIGKILL */
+ cgroup_enter_frozen();
freezable_schedule();
return true;
} else {
@@ -2332,6 +2336,43 @@ static void do_jobctl_trap(void)
}
}
+/**
+ * do_freezer_trap - handle the freezer jobctl trap
+ *
+ * Puts the task into frozen state, if only the task is not about to quit.
+ * In this case it drops JOBCTL_TRAP_FREEZE.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held,
+ * which is always released before returning.
+ */
+static void do_freezer_trap(void)
+ __releases(&current->sighand->siglock)
+{
+ /*
+ * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
+ * let's make another loop to give it a chance to be handled.
+ * In any case, we'll return back.
+ */
+ if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
+ JOBCTL_TRAP_FREEZE) {
+ spin_unlock_irq(&current->sighand->siglock);
+ return;
+ }
+
+ /*
+ * Now we're sure that there is no pending fatal signal and no
+ * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
+ * immediately (if there is a non-fatal signal pending), and
+ * put the task into sleep.
+ */
+ __set_current_state(TASK_INTERRUPTIBLE);
+ clear_thread_flag(TIF_SIGPENDING);
+ spin_unlock_irq(&current->sighand->siglock);
+ cgroup_enter_frozen();
+ freezable_schedule();
+}
+
static int ptrace_signal(int signr, kernel_siginfo_t *info)
{
/*
@@ -2452,9 +2493,24 @@ relock:
do_signal_stop(0))
goto relock;
- if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
- do_jobctl_trap();
+ if (unlikely(current->jobctl &
+ (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
+ if (current->jobctl & JOBCTL_TRAP_MASK) {
+ do_jobctl_trap();
+ spin_unlock_irq(&sighand->siglock);
+ } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
+ do_freezer_trap();
+
+ goto relock;
+ }
+
+ /*
+ * If the task is leaving the frozen state, let's update
+ * cgroup counters and reset the frozen bit.
+ */
+ if (unlikely(cgroup_task_frozen(current))) {
spin_unlock_irq(&sighand->siglock);
+ cgroup_leave_frozen(false);
goto relock;
}
@@ -2550,6 +2606,8 @@ relock:
fatal:
spin_unlock_irq(&sighand->siglock);
+ if (unlikely(cgroup_task_frozen(current)))
+ cgroup_leave_frozen(true);
/*
* Anything else is fatal, maybe with a core dump.