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-rw-r--r--kernel/exit.c68
1 files changed, 38 insertions, 30 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 4db0200..d8bd3b42 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -52,6 +52,7 @@
#include <linux/hw_breakpoint.h>
#include <linux/oom.h>
#include <linux/writeback.h>
+#include <linux/shm.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -424,7 +425,7 @@ void daemonize(const char *name, ...)
*/
exit_mm(current);
/*
- * We don't want to have TIF_FREEZE set if the system-wide hibernation
+ * We don't want to get frozen, in case system-wide hibernation
* or suspend transition begins right now.
*/
current->flags |= (PF_NOFREEZE | PF_KTHREAD);
@@ -686,11 +687,11 @@ static void exit_mm(struct task_struct * tsk)
}
/*
- * When we die, we re-parent all our children.
- * Try to give them to another thread in our thread
- * group, and if no such member exists, give it to
- * the child reaper process (ie "init") in our pid
- * space.
+ * When we die, we re-parent all our children, and try to:
+ * 1. give them to another thread in our thread group, if such a member exists
+ * 2. give it to the first ancestor process which prctl'd itself as a
+ * child_subreaper for its children (like a service manager)
+ * 3. give it to the init process (PID 1) in our pid namespace
*/
static struct task_struct *find_new_reaper(struct task_struct *father)
__releases(&tasklist_lock)
@@ -710,8 +711,11 @@ static struct task_struct *find_new_reaper(struct task_struct *father)
if (unlikely(pid_ns->child_reaper == father)) {
write_unlock_irq(&tasklist_lock);
- if (unlikely(pid_ns == &init_pid_ns))
- panic("Attempted to kill init!");
+ if (unlikely(pid_ns == &init_pid_ns)) {
+ panic("Attempted to kill init! exitcode=0x%08x\n",
+ father->signal->group_exit_code ?:
+ father->exit_code);
+ }
zap_pid_ns_processes(pid_ns);
write_lock_irq(&tasklist_lock);
@@ -721,6 +725,29 @@ static struct task_struct *find_new_reaper(struct task_struct *father)
* forget_original_parent() must move them somewhere.
*/
pid_ns->child_reaper = init_pid_ns.child_reaper;
+ } else if (father->signal->has_child_subreaper) {
+ struct task_struct *reaper;
+
+ /*
+ * Find the first ancestor marked as child_subreaper.
+ * Note that the code below checks same_thread_group(reaper,
+ * pid_ns->child_reaper). This is what we need to DTRT in a
+ * PID namespace. However we still need the check above, see
+ * http://marc.info/?l=linux-kernel&m=131385460420380
+ */
+ for (reaper = father->real_parent;
+ reaper != &init_task;
+ reaper = reaper->real_parent) {
+ if (same_thread_group(reaper, pid_ns->child_reaper))
+ break;
+ if (!reaper->signal->is_child_subreaper)
+ continue;
+ thread = reaper;
+ do {
+ if (!(thread->flags & PF_EXITING))
+ return reaper;
+ } while_each_thread(reaper, thread);
+ }
}
return pid_ns->child_reaper;
@@ -818,25 +845,6 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
if (group_dead)
kill_orphaned_pgrp(tsk->group_leader, NULL);
- /* Let father know we died
- *
- * Thread signals are configurable, but you aren't going to use
- * that to send signals to arbitrary processes.
- * That stops right now.
- *
- * If the parent exec id doesn't match the exec id we saved
- * when we started then we know the parent has changed security
- * domain.
- *
- * If our self_exec id doesn't match our parent_exec_id then
- * we have changed execution domain as these two values started
- * the same after a fork.
- */
- if (thread_group_leader(tsk) && tsk->exit_signal != SIGCHLD &&
- (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
- tsk->self_exec_id != tsk->parent_exec_id))
- tsk->exit_signal = SIGCHLD;
-
if (unlikely(tsk->ptrace)) {
int sig = thread_group_leader(tsk) &&
thread_group_empty(tsk) &&
@@ -935,8 +943,6 @@ void do_exit(long code)
schedule();
}
- exit_irq_thread();
-
exit_signals(tsk); /* sets PF_EXITING */
/*
* tsk->flags are checked in the futex code to protect against
@@ -945,6 +951,8 @@ void do_exit(long code)
smp_mb();
raw_spin_unlock_wait(&tsk->pi_lock);
+ exit_irq_thread();
+
if (unlikely(in_atomic()))
printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
@@ -953,7 +961,7 @@ void do_exit(long code)
acct_update_integrals(tsk);
/* sync mm's RSS info before statistics gathering */
if (tsk->mm)
- sync_mm_rss(tsk, tsk->mm);
+ sync_mm_rss(tsk->mm);
group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) {
hrtimer_cancel(&tsk->signal->real_timer);
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