x86/resctrl: Only show tasks' pid in current pid namespace

[ Upstream commit 2997d94 ] When writing a task id to the "tasks" file in an rdtgroup, rdtgroup_tasks_write() treats the pid as a number in the current pid namespace. But when reading the "tasks" file, rdtgroup_tasks_show() shows the list of global pids from the init namespace, which is confusing and incorrect. To be more robust, let the "tasks" file only show pids in the current pid namespace. Fixes: e02737d ("x86/intel_rdt: Add tasks files") Signed-off-by: Shawn Wang <[email protected]> Signed-off-by: Borislav Petkov (AMD) <[email protected]> Acked-by: Reinette Chatre <[email protected]> Acked-by: Fenghua Yu <[email protected]> Tested-by: Reinette Chatre <[email protected]> Link: https://lore.kernel.org/all/[email protected]/ Signed-off-by: Sasha Levin <[email protected]>
anthraxx · Jul 27, 2023 · 3db97cc · 3db97cc
1 parent 1a82005
commit 3db97cc
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -715,11 +715,15 @@ static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of,
 static void show_rdt_tasks(struct rdtgroup *r, struct seq_file *s)
 {
 	struct task_struct *p, *t;
+	pid_t pid;
 
 	rcu_read_lock();
 	for_each_process_thread(p, t) {
-		if (is_closid_match(t, r) || is_rmid_match(t, r))
-			seq_printf(s, "%d\n", t->pid);
+		if (is_closid_match(t, r) || is_rmid_match(t, r)) {
+			pid = task_pid_vnr(t);
+			if (pid)
+				seq_printf(s, "%d\n", pid);
+		}
 	}
 	rcu_read_unlock();
 }