summaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cred.c2
-rw-r--r--kernel/events/core.c12
-rw-r--r--kernel/exit.c4
-rw-r--r--kernel/fork.c5
-rw-r--r--kernel/kcmp.c8
-rw-r--r--kernel/pid.c13
-rw-r--r--kernel/pid_namespace.c38
-rw-r--r--kernel/signal.c2
8 files changed, 39 insertions, 45 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index 809a985b1793..71a792616917 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -675,8 +675,6 @@ void __init cred_init(void)
* The caller may change these controls afterwards if desired.
*
* Returns the new credentials or NULL if out of memory.
- *
- * Does not take, and does not return holding current->cred_replace_mutex.
*/
struct cred *prepare_kernel_cred(struct task_struct *daemon)
{
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 318435c5bf0b..e1459df73043 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1295,7 +1295,7 @@ static void put_ctx(struct perf_event_context *ctx)
* function.
*
* Lock order:
- * cred_guard_mutex
+ * exec_update_mutex
* task_struct::perf_event_mutex
* perf_event_context::mutex
* perf_event::child_mutex;
@@ -11425,14 +11425,14 @@ SYSCALL_DEFINE5(perf_event_open,
}
if (task) {
- err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
+ err = mutex_lock_interruptible(&task->signal->exec_update_mutex);
if (err)
goto err_task;
/*
* Reuse ptrace permission checks for now.
*
- * We must hold cred_guard_mutex across this and any potential
+ * We must hold exec_update_mutex across this and any potential
* perf_install_in_context() call for this new event to
* serialize against exec() altering our credentials (and the
* perf_event_exit_task() that could imply).
@@ -11721,7 +11721,7 @@ SYSCALL_DEFINE5(perf_event_open,
mutex_unlock(&ctx->mutex);
if (task) {
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
put_task_struct(task);
}
@@ -11757,7 +11757,7 @@ err_alloc:
free_event(event);
err_cred:
if (task)
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
err_task:
if (task)
put_task_struct(task);
@@ -12062,7 +12062,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
/*
* When a child task exits, feed back event values to parent events.
*
- * Can be called with cred_guard_mutex held when called from
+ * Can be called with exec_update_mutex held when called from
* install_exec_creds().
*/
void perf_event_exit_task(struct task_struct *child)
diff --git a/kernel/exit.c b/kernel/exit.c
index d70d47159640..389a88cb3081 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -182,6 +182,7 @@ void put_task_struct_rcu_user(struct task_struct *task)
void release_task(struct task_struct *p)
{
struct task_struct *leader;
+ struct pid *thread_pid;
int zap_leader;
repeat:
/* don't need to get the RCU readlock here - the process is dead and
@@ -190,11 +191,11 @@ repeat:
atomic_dec(&__task_cred(p)->user->processes);
rcu_read_unlock();
- proc_flush_task(p);
cgroup_release(p);
write_lock_irq(&tasklist_lock);
ptrace_release_task(p);
+ thread_pid = get_pid(p->thread_pid);
__exit_signal(p);
/*
@@ -217,6 +218,7 @@ repeat:
}
write_unlock_irq(&tasklist_lock);
+ proc_flush_pid(thread_pid);
release_thread(p);
put_task_struct_rcu_user(p);
diff --git a/kernel/fork.c b/kernel/fork.c
index d90af13431c7..25f38a84dbfd 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1224,7 +1224,7 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
struct mm_struct *mm;
int err;
- err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ err = mutex_lock_killable(&task->signal->exec_update_mutex);
if (err)
return ERR_PTR(err);
@@ -1234,7 +1234,7 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
mmput(mm);
mm = ERR_PTR(-EACCES);
}
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
return mm;
}
@@ -1594,6 +1594,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->oom_score_adj_min = current->signal->oom_score_adj_min;
mutex_init(&sig->cred_guard_mutex);
+ mutex_init(&sig->exec_update_mutex);
return 0;
}
diff --git a/kernel/kcmp.c b/kernel/kcmp.c
index a0e3d7a0e8b8..b3ff9288c6cc 100644
--- a/kernel/kcmp.c
+++ b/kernel/kcmp.c
@@ -173,8 +173,8 @@ SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
/*
* One should have enough rights to inspect task details.
*/
- ret = kcmp_lock(&task1->signal->cred_guard_mutex,
- &task2->signal->cred_guard_mutex);
+ ret = kcmp_lock(&task1->signal->exec_update_mutex,
+ &task2->signal->exec_update_mutex);
if (ret)
goto err;
if (!ptrace_may_access(task1, PTRACE_MODE_READ_REALCREDS) ||
@@ -229,8 +229,8 @@ SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
}
err_unlock:
- kcmp_unlock(&task1->signal->cred_guard_mutex,
- &task2->signal->cred_guard_mutex);
+ kcmp_unlock(&task1->signal->exec_update_mutex,
+ &task2->signal->exec_update_mutex);
err:
put_task_struct(task1);
put_task_struct(task2);
diff --git a/kernel/pid.c b/kernel/pid.c
index 647b4bb457b5..bc21c0fb26d8 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -144,9 +144,6 @@ void free_pid(struct pid *pid)
/* Handle a fork failure of the first process */
WARN_ON(ns->child_reaper);
ns->pid_allocated = 0;
- /* fall through */
- case 0:
- schedule_work(&ns->proc_work);
break;
}
@@ -257,17 +254,13 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
*/
retval = -ENOMEM;
- if (unlikely(is_child_reaper(pid))) {
- if (pid_ns_prepare_proc(ns))
- goto out_free;
- }
-
get_pid_ns(ns);
refcount_set(&pid->count, 1);
for (type = 0; type < PIDTYPE_MAX; ++type)
INIT_HLIST_HEAD(&pid->tasks[type]);
init_waitqueue_head(&pid->wait_pidfd);
+ INIT_HLIST_HEAD(&pid->inodes);
upid = pid->numbers + ns->level;
spin_lock_irq(&pidmap_lock);
@@ -594,7 +587,7 @@ static struct file *__pidfd_fget(struct task_struct *task, int fd)
struct file *file;
int ret;
- ret = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ ret = mutex_lock_killable(&task->signal->exec_update_mutex);
if (ret)
return ERR_PTR(ret);
@@ -603,7 +596,7 @@ static struct file *__pidfd_fget(struct task_struct *task, int fd)
else
file = ERR_PTR(-EPERM);
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
return file ?: ERR_PTR(-EBADF);
}
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index d40017e79ebe..01f8ba32cc0c 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -57,12 +57,6 @@ static struct kmem_cache *create_pid_cachep(unsigned int level)
return READ_ONCE(*pkc);
}
-static void proc_cleanup_work(struct work_struct *work)
-{
- struct pid_namespace *ns = container_of(work, struct pid_namespace, proc_work);
- pid_ns_release_proc(ns);
-}
-
static struct ucounts *inc_pid_namespaces(struct user_namespace *ns)
{
return inc_ucount(ns, current_euid(), UCOUNT_PID_NAMESPACES);
@@ -114,7 +108,6 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
ns->user_ns = get_user_ns(user_ns);
ns->ucounts = ucounts;
ns->pid_allocated = PIDNS_ADDING;
- INIT_WORK(&ns->proc_work, proc_cleanup_work);
return ns;
@@ -231,20 +224,27 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
} while (rc != -ECHILD);
/*
- * kernel_wait4() above can't reap the EXIT_DEAD children but we do not
- * really care, we could reparent them to the global init. We could
- * exit and reap ->child_reaper even if it is not the last thread in
- * this pid_ns, free_pid(pid_allocated == 0) calls proc_cleanup_work(),
- * pid_ns can not go away until proc_kill_sb() drops the reference.
+ * kernel_wait4() misses EXIT_DEAD children, and EXIT_ZOMBIE
+ * process whose parents processes are outside of the pid
+ * namespace. Such processes are created with setns()+fork().
+ *
+ * If those EXIT_ZOMBIE processes are not reaped by their
+ * parents before their parents exit, they will be reparented
+ * to pid_ns->child_reaper. Thus pidns->child_reaper needs to
+ * stay valid until they all go away.
+ *
+ * The code relies on the the pid_ns->child_reaper ignoring
+ * SIGCHILD to cause those EXIT_ZOMBIE processes to be
+ * autoreaped if reparented.
*
- * But this ns can also have other tasks injected by setns()+fork().
- * Again, ignoring the user visible semantics we do not really need
- * to wait until they are all reaped, but they can be reparented to
- * us and thus we need to ensure that pid->child_reaper stays valid
- * until they all go away. See free_pid()->wake_up_process().
+ * Semantically it is also desirable to wait for EXIT_ZOMBIE
+ * processes before allowing the child_reaper to be reaped, as
+ * that gives the invariant that when the init process of a
+ * pid namespace is reaped all of the processes in the pid
+ * namespace are gone.
*
- * We rely on ignored SIGCHLD, an injected zombie must be autoreaped
- * if reparented.
+ * Once all of the other tasks are gone from the pid_namespace
+ * free_pid() will awaken this task.
*/
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
diff --git a/kernel/signal.c b/kernel/signal.c
index 5b2396350dd1..e58a6c619824 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1931,7 +1931,7 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
* This is only possible if parent == real_parent.
* Check if it has changed security domain.
*/
- if (tsk->parent_exec_id != tsk->parent->self_exec_id)
+ if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
sig = SIGCHLD;
}
generated by cgit v1.2.3-70-g09d2 (git 2.48.1) at 2025-02-26 22:43:21 +0000