[PATCH 2/2] signals: replace p->pid == 1 check with a check for task_child_reaper

From: Daniel Hokka Zakrisson
Date: Thu Jul 17 2008 - 11:17:45 EST


p->pid == 1 is insufficient when there are multiple pid namespaces.
Instead, check whether the task is in the current task's
child reaper's thread group.

Signed-off-by: Daniel Hokka Zakrisson <daniel@xxxxxxxxx>

diff --git a/kernel/signal.c b/kernel/signal.c
index 93713a5..be932b9 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1142,10 +1142,20 @@ static int kill_something_info(int sig, struct siginfo *info, int pid)
pid ? find_vpid(-pid) : task_pgrp(current));
} else {
int retval = 0, count = 0;
- struct task_struct * p;
+ struct task_struct *p, *reaper = task_child_reaper(current);
+
+ /*
+ * The reaper has died, so there's probably a
+ * SIGKILL pending. Return.
+ */
+ if (unlikely(!reaper)) {
+ ret = -ESRCH;
+ goto out;
+ }

for_each_process(p) {
- if (p->pid > 1 && !same_thread_group(p, current) &&
+ if (!same_thread_group(p, reaper) &&
+ !same_thread_group(p, current) &&
task_in_pid_ns(p, current->nsproxy->pid_ns)) {
int err = group_send_sig_info(sig, info, p);
++count;
@@ -1155,6 +1165,7 @@ static int kill_something_info(int sig, struct siginfo *info, int pid)
}
ret = count ? retval : -ESRCH;
}
+out:
read_unlock(&tasklist_lock);

return ret;
--
1.5.5.1
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