Merge branches 'sched-urgent-for-linus' and 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull stack vmap fixups from Thomas Gleixner:
"Two small patches related to sched_show_task():
- make sure to hold a reference on the task stack while accessing it
- remove the thread_saved_pc printout
.. and add a sanity check into release_task_stack() to catch problems
with task stack references"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/core: Remove pointless printout in sched_show_task()
sched/core: Fix oops in sched_show_task()
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
fork: Add task stack refcounting sanity check and prevent premature task stack freeing
diff --git a/kernel/fork.c b/kernel/fork.c
index 623259f..997ac1d5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -315,6 +315,9 @@
static void release_task_stack(struct task_struct *tsk)
{
+ if (WARN_ON(tsk->state != TASK_DEAD))
+ return; /* Better to leak the stack than to free prematurely */
+
account_kernel_stack(tsk, -1);
arch_release_thread_stack(tsk->stack);
free_thread_stack(tsk);
@@ -1862,6 +1865,7 @@
atomic_dec(&p->cred->user->processes);
exit_creds(p);
bad_fork_free:
+ p->state = TASK_DEAD;
put_task_stack(p);
free_task(p);
fork_out:
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 42d4027..154fd68 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5192,21 +5192,14 @@
int ppid;
unsigned long state = p->state;
+ if (!try_get_task_stack(p))
+ return;
if (state)
state = __ffs(state) + 1;
printk(KERN_INFO "%-15.15s %c", p->comm,
state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
-#if BITS_PER_LONG == 32
- if (state == TASK_RUNNING)
- printk(KERN_CONT " running ");
- else
- printk(KERN_CONT " %08lx ", thread_saved_pc(p));
-#else
if (state == TASK_RUNNING)
printk(KERN_CONT " running task ");
- else
- printk(KERN_CONT " %016lx ", thread_saved_pc(p));
-#endif
#ifdef CONFIG_DEBUG_STACK_USAGE
free = stack_not_used(p);
#endif
@@ -5221,6 +5214,7 @@
print_worker_info(KERN_INFO, p);
show_stack(p, NULL);
+ put_task_stack(p);
}
void show_state_filter(unsigned long state_filter)
