#include <linux/pipe_fs_i.h>
#include <linux/audit.h> /* for audit_free() */
#include <linux/resource.h>
-#include <linux/blkdev.h>
#include <linux/task_io_accounting_ops.h>
-#include <linux/tracehook.h>
+#include <linux/blkdev.h>
+#include <linux/task_work.h>
#include <linux/fs_struct.h>
#include <linux/init_task.h>
#include <linux/perf_event.h>
#include <linux/writeback.h>
#include <linux/shm.h>
#include <linux/kcov.h>
+#include <linux/kmsan.h>
#include <linux/random.h>
#include <linux/rcuwait.h>
#include <linux/compat.h>
-
+#include <linux/io_uring.h>
+#include <linux/kprobes.h>
+#include <linux/rethook.h>
+#include <linux/sysfs.h>
+#include <linux/user_events.h>
#include <linux/uaccess.h>
+
+#include <uapi/linux/wait.h>
+
#include <asm/unistd.h>
-#include <asm/pgtable.h>
#include <asm/mmu_context.h>
+#include "exit.h"
+
+/*
+ * The default value should be high enough to not crash a system that randomly
+ * crashes its kernel from time to time, but low enough to at least not permit
+ * overflowing 32-bit refcounts or the ldsem writer count.
+ */
+static unsigned int oops_limit = 10000;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_exit_table[] = {
+ {
+ .procname = "oops_limit",
+ .data = &oops_limit,
+ .maxlen = sizeof(oops_limit),
+ .mode = 0644,
+ .proc_handler = proc_douintvec,
+ },
+ { }
+};
+
+static __init int kernel_exit_sysctls_init(void)
+{
+ register_sysctl_init("kernel", kern_exit_table);
+ return 0;
+}
+late_initcall(kernel_exit_sysctls_init);
+#endif
+
+static atomic_t oops_count = ATOMIC_INIT(0);
+
+#ifdef CONFIG_SYSFS
+static ssize_t oops_count_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *page)
+{
+ return sysfs_emit(page, "%d\n", atomic_read(&oops_count));
+}
+
+static struct kobj_attribute oops_count_attr = __ATTR_RO(oops_count);
+
+static __init int kernel_exit_sysfs_init(void)
+{
+ sysfs_add_file_to_group(kernel_kobj, &oops_count_attr.attr, NULL);
+ return 0;
+}
+late_initcall(kernel_exit_sysfs_init);
+#endif
+
static void __unhash_process(struct task_struct *p, bool group_dead)
{
nr_threads--;
list_del_init(&p->sibling);
__this_cpu_dec(process_counts);
}
- list_del_rcu(&p->thread_group);
list_del_rcu(&p->thread_node);
}
struct signal_struct *sig = tsk->signal;
bool group_dead = thread_group_leader(tsk);
struct sighand_struct *sighand;
- struct tty_struct *uninitialized_var(tty);
+ struct tty_struct *tty;
u64 utime, stime;
sighand = rcu_dereference_check(tsk->sighand,
#ifdef CONFIG_POSIX_TIMERS
posix_cpu_timers_exit(tsk);
- if (group_dead) {
+ if (group_dead)
posix_cpu_timers_exit_group(tsk);
- } else {
- /*
- * This can only happen if the caller is de_thread().
- * FIXME: this is the temporary hack, we should teach
- * posix-cpu-timers to handle this case correctly.
- */
- if (unlikely(has_group_leader_pid(tsk)))
- posix_cpu_timers_exit_group(tsk);
- }
#endif
if (group_dead) {
* then notify it:
*/
if (sig->notify_count > 0 && !--sig->notify_count)
- wake_up_process(sig->group_exit_task);
+ wake_up_process(sig->group_exec_task);
if (tsk == sig->curr_target)
sig->curr_target = next_thread(tsk);
{
struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+ kprobe_flush_task(tsk);
+ rethook_flush_task(tsk);
perf_event_delayed_put(tsk);
trace_sched_process_free(tsk);
put_task_struct(tsk);
}
+void put_task_struct_rcu_user(struct task_struct *task)
+{
+ if (refcount_dec_and_test(&task->rcu_users))
+ call_rcu(&task->rcu, delayed_put_task_struct);
+}
+
+void __weak release_thread(struct task_struct *dead_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
* can't be modifying its own credentials. But shut RCU-lockdep up */
rcu_read_lock();
- atomic_dec(&__task_cred(p)->user->processes);
+ dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
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);
/*
}
write_unlock_irq(&tasklist_lock);
- cgroup_release(p);
+ seccomp_filter_release(p);
+ proc_flush_pid(thread_pid);
+ put_pid(thread_pid);
release_thread(p);
- call_rcu(&p->rcu, delayed_put_task_struct);
+ put_task_struct_rcu_user(p);
p = leader;
if (unlikely(zap_leader))
goto repeat;
}
-/*
- * Note that if this function returns a valid task_struct pointer (!NULL)
- * task->usage must remain >0 for the duration of the RCU critical section.
- */
-struct task_struct *task_rcu_dereference(struct task_struct **ptask)
-{
- struct sighand_struct *sighand;
- struct task_struct *task;
-
- /*
- * We need to verify that release_task() was not called and thus
- * delayed_put_task_struct() can't run and drop the last reference
- * before rcu_read_unlock(). We check task->sighand != NULL,
- * but we can read the already freed and reused memory.
- */
-retry:
- task = rcu_dereference(*ptask);
- if (!task)
- return NULL;
-
- probe_kernel_address(&task->sighand, sighand);
-
- /*
- * Pairs with atomic_dec_and_test() in put_task_struct(). If this task
- * was already freed we can not miss the preceding update of this
- * pointer.
- */
- smp_rmb();
- if (unlikely(task != READ_ONCE(*ptask)))
- goto retry;
-
- /*
- * We've re-checked that "task == *ptask", now we have two different
- * cases:
- *
- * 1. This is actually the same task/task_struct. In this case
- * sighand != NULL tells us it is still alive.
- *
- * 2. This is another task which got the same memory for task_struct.
- * We can't know this of course, and we can not trust
- * sighand != NULL.
- *
- * In this case we actually return a random value, but this is
- * correct.
- *
- * If we return NULL - we can pretend that we actually noticed that
- * *ptask was updated when the previous task has exited. Or pretend
- * that probe_slab_address(&sighand) reads NULL.
- *
- * If we return the new task (because sighand is not NULL for any
- * reason) - this is fine too. This (new) task can't go away before
- * another gp pass.
- *
- * And note: We could even eliminate the false positive if re-read
- * task->sighand once again to avoid the falsely NULL. But this case
- * is very unlikely so we don't care.
- */
- if (!sighand)
- return NULL;
-
- return task;
-}
-
-void rcuwait_wake_up(struct rcuwait *w)
+int rcuwait_wake_up(struct rcuwait *w)
{
+ int ret = 0;
struct task_struct *task;
rcu_read_lock();
/*
* Order condition vs @task, such that everything prior to the load
* of @task is visible. This is the condition as to why the user called
- * rcuwait_trywake() in the first place. Pairs with set_current_state()
+ * rcuwait_wake() in the first place. Pairs with set_current_state()
* barrier (A) in rcuwait_wait_event().
*
* WAIT WAKE
*/
smp_mb(); /* (B) */
- /*
- * Avoid using task_rcu_dereference() magic as long as we are careful,
- * see comment in rcuwait_wait_event() regarding ->exit_state.
- */
task = rcu_dereference(w->task);
if (task)
- wake_up_process(task);
+ ret = wake_up_process(task);
rcu_read_unlock();
+
+ return ret;
}
+EXPORT_SYMBOL_GPL(rcuwait_wake_up);
/*
* Determine if a process group is "orphaned", according to the POSIX
}
}
+static void coredump_task_exit(struct task_struct *tsk)
+{
+ struct core_state *core_state;
+
+ /*
+ * Serialize with any possible pending coredump.
+ * We must hold siglock around checking core_state
+ * and setting PF_POSTCOREDUMP. The core-inducing thread
+ * will increment ->nr_threads for each thread in the
+ * group without PF_POSTCOREDUMP set.
+ */
+ spin_lock_irq(&tsk->sighand->siglock);
+ tsk->flags |= PF_POSTCOREDUMP;
+ core_state = tsk->signal->core_state;
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ /* The vhost_worker does not particpate in coredumps */
+ if (core_state &&
+ ((tsk->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)) {
+ struct core_thread self;
+
+ self.task = current;
+ if (self.task->flags & PF_SIGNALED)
+ self.next = xchg(&core_state->dumper.next, &self);
+ else
+ self.task = NULL;
+ /*
+ * Implies mb(), the result of xchg() must be visible
+ * to core_state->dumper.
+ */
+ if (atomic_dec_and_test(&core_state->nr_threads))
+ complete(&core_state->startup);
+
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
+ if (!self.task) /* see coredump_finish() */
+ break;
+ schedule();
+ }
+ __set_current_state(TASK_RUNNING);
+ }
+}
+
#ifdef CONFIG_MEMCG
/*
* A task is exiting. If it owned this mm, find a new owner for the mm.
goto retry;
}
WRITE_ONCE(mm->owner, c);
+ lru_gen_migrate_mm(mm);
task_unlock(c);
put_task_struct(c);
}
static void exit_mm(void)
{
struct mm_struct *mm = current->mm;
- struct core_state *core_state;
- mm_release(current, mm);
+ exit_mm_release(current, mm);
if (!mm)
return;
- sync_mm_rss(mm);
- /*
- * Serialize with any possible pending coredump.
- * We must hold mmap_sem around checking core_state
- * and clearing tsk->mm. The core-inducing thread
- * will increment ->nr_threads for each thread in the
- * group with ->mm != NULL.
- */
- down_read(&mm->mmap_sem);
- core_state = mm->core_state;
- if (core_state) {
- struct core_thread self;
-
- up_read(&mm->mmap_sem);
-
- self.task = current;
- self.next = xchg(&core_state->dumper.next, &self);
- /*
- * Implies mb(), the result of xchg() must be visible
- * to core_state->dumper.
- */
- if (atomic_dec_and_test(&core_state->nr_threads))
- complete(&core_state->startup);
-
- for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (!self.task) /* see coredump_finish() */
- break;
- freezable_schedule();
- }
- __set_current_state(TASK_RUNNING);
- down_read(&mm->mmap_sem);
- }
- mmgrab(mm);
+ mmap_read_lock(mm);
+ mmgrab_lazy_tlb(mm);
BUG_ON(mm != current->active_mm);
/* more a memory barrier than a real lock */
task_lock(current);
+ /*
+ * When a thread stops operating on an address space, the loop
+ * in membarrier_private_expedited() may not observe that
+ * tsk->mm, and the loop in membarrier_global_expedited() may
+ * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
+ * rq->membarrier_state, so those would not issue an IPI.
+ * Membarrier requires a memory barrier after accessing
+ * user-space memory, before clearing tsk->mm or the
+ * rq->membarrier_state.
+ */
+ smp_mb__after_spinlock();
+ local_irq_disable();
current->mm = NULL;
- up_read(&mm->mmap_sem);
+ membarrier_update_current_mm(NULL);
enter_lazy_tlb(mm, current);
+ local_irq_enable();
task_unlock(current);
+ mmap_read_unlock(mm);
mm_update_next_owner(mm);
mmput(mm);
if (test_thread_flag(TIF_MEMDIE))
}
write_unlock_irq(&tasklist_lock);
- if (unlikely(pid_ns == &init_pid_ns)) {
- panic("Attempted to kill init! exitcode=0x%08x\n",
- father->signal->group_exit_code ?: father->exit_code);
- }
list_for_each_entry_safe(p, n, dead, ptrace_entry) {
list_del_init(&p->ptrace_entry);
reaper = find_new_reaper(father, reaper);
list_for_each_entry(p, &father->children, sibling) {
for_each_thread(p, t) {
- t->real_parent = reaper;
- BUG_ON((!t->ptrace) != (t->parent == father));
+ RCU_INIT_POINTER(t->real_parent, reaper);
+ BUG_ON((!t->ptrace) != (rcu_access_pointer(t->parent) == father));
if (likely(!t->ptrace))
t->parent = t->real_parent;
if (t->pdeath_signal)
if (group_dead)
kill_orphaned_pgrp(tsk->group_leader, NULL);
+ tsk->exit_state = EXIT_ZOMBIE;
+ /*
+ * sub-thread or delay_group_leader(), wake up the
+ * PIDFD_THREAD waiters.
+ */
+ if (!thread_group_empty(tsk))
+ do_notify_pidfd(tsk);
+
if (unlikely(tsk->ptrace)) {
int sig = thread_group_leader(tsk) &&
thread_group_empty(tsk) &&
autoreap = true;
}
- tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE;
- if (tsk->exit_state == EXIT_DEAD)
+ if (autoreap) {
+ tsk->exit_state = EXIT_DEAD;
list_add(&tsk->ptrace_entry, &dead);
+ }
/* mt-exec, de_thread() is waiting for group leader */
if (unlikely(tsk->signal->notify_count < 0))
- wake_up_process(tsk->signal->group_exit_task);
+ wake_up_process(tsk->signal->group_exec_task);
write_unlock_irq(&tasklist_lock);
list_for_each_entry_safe(p, n, &dead, ptrace_entry) {
static inline void check_stack_usage(void) {}
#endif
+static void synchronize_group_exit(struct task_struct *tsk, long code)
+{
+ struct sighand_struct *sighand = tsk->sighand;
+ struct signal_struct *signal = tsk->signal;
+
+ spin_lock_irq(&sighand->siglock);
+ signal->quick_threads--;
+ if ((signal->quick_threads == 0) &&
+ !(signal->flags & SIGNAL_GROUP_EXIT)) {
+ signal->flags = SIGNAL_GROUP_EXIT;
+ signal->group_exit_code = code;
+ signal->group_stop_count = 0;
+ }
+ spin_unlock_irq(&sighand->siglock);
+}
+
void __noreturn do_exit(long code)
{
struct task_struct *tsk = current;
int group_dead;
- profile_task_exit(tsk);
- kcov_task_exit(tsk);
+ WARN_ON(irqs_disabled());
- WARN_ON(blk_needs_flush_plug(tsk));
+ synchronize_group_exit(tsk, code);
- if (unlikely(in_interrupt()))
- panic("Aiee, killing interrupt handler!");
- if (unlikely(!tsk->pid))
- panic("Attempted to kill the idle task!");
+ WARN_ON(tsk->plug);
- /*
- * If do_exit is called because this processes oopsed, it's possible
- * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
- * continuing. Amongst other possible reasons, this is to prevent
- * mm_release()->clear_child_tid() from writing to a user-controlled
- * kernel address.
- */
- set_fs(USER_DS);
+ kcov_task_exit(tsk);
+ kmsan_task_exit(tsk);
+ coredump_task_exit(tsk);
ptrace_event(PTRACE_EVENT_EXIT, code);
+ user_events_exit(tsk);
- validate_creds_for_do_exit(tsk);
-
- /*
- * We're taking recursive faults here in do_exit. Safest is to just
- * leave this task alone and wait for reboot.
- */
- if (unlikely(tsk->flags & PF_EXITING)) {
- pr_alert("Fixing recursive fault but reboot is needed!\n");
- /*
- * We can do this unlocked here. The futex code uses
- * this flag just to verify whether the pi state
- * cleanup has been done or not. In the worst case it
- * loops once more. We pretend that the cleanup was
- * done as there is no way to return. Either the
- * OWNER_DIED bit is set by now or we push the blocked
- * task into the wait for ever nirwana as well.
- */
- tsk->flags |= PF_EXITPIDONE;
- set_current_state(TASK_UNINTERRUPTIBLE);
- schedule();
- }
-
+ io_uring_files_cancel();
exit_signals(tsk); /* sets PF_EXITING */
- /*
- * Ensure that all new tsk->pi_lock acquisitions must observe
- * PF_EXITING. Serializes against futex.c:attach_to_pi_owner().
- */
- smp_mb();
- /*
- * Ensure that we must observe the pi_state in exit_mm() ->
- * mm_release() -> exit_pi_state_list().
- */
- raw_spin_lock_irq(&tsk->pi_lock);
- raw_spin_unlock_irq(&tsk->pi_lock);
- if (unlikely(in_atomic())) {
- pr_info("note: %s[%d] exited with preempt_count %d\n",
- current->comm, task_pid_nr(current),
- preempt_count());
- preempt_count_set(PREEMPT_ENABLED);
- }
-
- /* sync mm's RSS info before statistics gathering */
- if (tsk->mm)
- sync_mm_rss(tsk->mm);
acct_update_integrals(tsk);
group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) {
+ /*
+ * If the last thread of global init has exited, panic
+ * immediately to get a useable coredump.
+ */
+ if (unlikely(is_global_init(tsk)))
+ panic("Attempted to kill init! exitcode=0x%08x\n",
+ tsk->signal->group_exit_code ?: (int)code);
+
#ifdef CONFIG_POSIX_TIMERS
hrtimer_cancel(&tsk->signal->real_timer);
- exit_itimers(tsk->signal);
+ exit_itimers(tsk);
#endif
if (tsk->mm)
setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
exit_task_namespaces(tsk);
exit_task_work(tsk);
exit_thread(tsk);
- exit_umh(tsk);
/*
* Flush inherited counters to the parent - before the parent
* Make sure we are holding no locks:
*/
debug_check_no_locks_held();
- /*
- * We can do this unlocked here. The futex code uses this flag
- * just to verify whether the pi state cleanup has been done
- * or not. In the worst case it loops once more.
- */
- tsk->flags |= PF_EXITPIDONE;
if (tsk->io_context)
exit_io_context(tsk);
if (tsk->task_frag.page)
put_page(tsk->task_frag.page);
- validate_creds_for_do_exit(tsk);
+ exit_task_stack_account(tsk);
check_stack_usage();
preempt_disable();
lockdep_free_task(tsk);
do_task_dead();
}
-EXPORT_SYMBOL_GPL(do_exit);
-void complete_and_exit(struct completion *comp, long code)
+void __noreturn make_task_dead(int signr)
{
- if (comp)
- complete(comp);
+ /*
+ * Take the task off the cpu after something catastrophic has
+ * happened.
+ *
+ * We can get here from a kernel oops, sometimes with preemption off.
+ * Start by checking for critical errors.
+ * Then fix up important state like USER_DS and preemption.
+ * Then do everything else.
+ */
+ struct task_struct *tsk = current;
+ unsigned int limit;
+
+ if (unlikely(in_interrupt()))
+ panic("Aiee, killing interrupt handler!");
+ if (unlikely(!tsk->pid))
+ panic("Attempted to kill the idle task!");
+
+ if (unlikely(irqs_disabled())) {
+ pr_info("note: %s[%d] exited with irqs disabled\n",
+ current->comm, task_pid_nr(current));
+ local_irq_enable();
+ }
+ if (unlikely(in_atomic())) {
+ pr_info("note: %s[%d] exited with preempt_count %d\n",
+ current->comm, task_pid_nr(current),
+ preempt_count());
+ preempt_count_set(PREEMPT_ENABLED);
+ }
+
+ /*
+ * Every time the system oopses, if the oops happens while a reference
+ * to an object was held, the reference leaks.
+ * If the oops doesn't also leak memory, repeated oopsing can cause
+ * reference counters to wrap around (if they're not using refcount_t).
+ * This means that repeated oopsing can make unexploitable-looking bugs
+ * exploitable through repeated oopsing.
+ * To make sure this can't happen, place an upper bound on how often the
+ * kernel may oops without panic().
+ */
+ limit = READ_ONCE(oops_limit);
+ if (atomic_inc_return(&oops_count) >= limit && limit)
+ panic("Oopsed too often (kernel.oops_limit is %d)", limit);
+
+ /*
+ * We're taking recursive faults here in make_task_dead. Safest is to just
+ * leave this task alone and wait for reboot.
+ */
+ if (unlikely(tsk->flags & PF_EXITING)) {
+ pr_alert("Fixing recursive fault but reboot is needed!\n");
+ futex_exit_recursive(tsk);
+ tsk->exit_state = EXIT_DEAD;
+ refcount_inc(&tsk->rcu_users);
+ do_task_dead();
+ }
- do_exit(code);
+ do_exit(signr);
}
-EXPORT_SYMBOL(complete_and_exit);
SYSCALL_DEFINE1(exit, int, error_code)
{
* Take down every thread in the group. This is called by fatal signals
* as well as by sys_exit_group (below).
*/
-void
+void __noreturn
do_group_exit(int exit_code)
{
struct signal_struct *sig = current->signal;
- BUG_ON(exit_code & 0x80); /* core dumps don't get here */
-
- if (signal_group_exit(sig))
+ if (sig->flags & SIGNAL_GROUP_EXIT)
exit_code = sig->group_exit_code;
- else if (!thread_group_empty(current)) {
+ else if (sig->group_exec_task)
+ exit_code = 0;
+ else {
struct sighand_struct *const sighand = current->sighand;
spin_lock_irq(&sighand->siglock);
- if (signal_group_exit(sig))
+ if (sig->flags & SIGNAL_GROUP_EXIT)
/* Another thread got here before we took the lock. */
exit_code = sig->group_exit_code;
+ else if (sig->group_exec_task)
+ exit_code = 0;
else {
sig->group_exit_code = exit_code;
sig->flags = SIGNAL_GROUP_EXIT;
return 0;
}
-struct waitid_info {
- pid_t pid;
- uid_t uid;
- int status;
- int cause;
-};
-
-struct wait_opts {
- enum pid_type wo_type;
- int wo_flags;
- struct pid *wo_pid;
-
- struct waitid_info *wo_info;
- int wo_stat;
- struct rusage *wo_rusage;
-
- wait_queue_entry_t child_wait;
- int notask_error;
-};
-
static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
{
return wo->wo_type == PIDTYPE_MAX ||
return 0;
if (unlikely(wo->wo_flags & WNOWAIT)) {
- status = p->exit_code;
+ status = (p->signal->flags & SIGNAL_GROUP_EXIT)
+ ? p->signal->group_exit_code : p->exit_code;
get_task_struct(p);
read_unlock(&tasklist_lock);
sched_annotate_sleep();
* p->signal fields because the whole thread group is dead
* and nobody can change them.
*
- * psig->stats_lock also protects us from our sub-theads
- * which can reap other children at the same time. Until
- * we change k_getrusage()-like users to rely on this lock
- * we have to take ->siglock as well.
+ * psig->stats_lock also protects us from our sub-threads
+ * which can reap other children at the same time.
*
* We use thread_group_cputime_adjusted() to get times for
* the thread group, which consolidates times for all threads
* in the group including the group leader.
*/
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
- spin_lock_irq(¤t->sighand->siglock);
- write_seqlock(&psig->stats_lock);
+ write_seqlock_irq(&psig->stats_lock);
psig->cutime += tgutime + sig->cutime;
psig->cstime += tgstime + sig->cstime;
psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
psig->cmaxrss = maxrss;
task_io_accounting_add(&psig->ioac, &p->ioac);
task_io_accounting_add(&psig->ioac, &sig->ioac);
- write_sequnlock(&psig->stats_lock);
- spin_unlock_irq(¤t->sighand->siglock);
+ write_sequnlock_irq(&psig->stats_lock);
}
if (wo->wo_rusage)
return 0;
}
+bool pid_child_should_wake(struct wait_opts *wo, struct task_struct *p)
+{
+ if (!eligible_pid(wo, p))
+ return false;
+
+ if ((wo->wo_flags & __WNOTHREAD) && wo->child_wait.private != p->parent)
+ return false;
+
+ return true;
+}
+
static int child_wait_callback(wait_queue_entry_t *wait, unsigned mode,
int sync, void *key)
{
child_wait);
struct task_struct *p = key;
- if (!eligible_pid(wo, p))
- return 0;
-
- if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
- return 0;
+ if (pid_child_should_wake(wo, p))
+ return default_wake_function(wait, mode, sync, key);
- return default_wake_function(wait, mode, sync, key);
+ return 0;
}
void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
{
__wake_up_sync_key(&parent->signal->wait_chldexit,
- TASK_INTERRUPTIBLE, 1, p);
+ TASK_INTERRUPTIBLE, p);
}
-static long do_wait(struct wait_opts *wo)
+static bool is_effectively_child(struct wait_opts *wo, bool ptrace,
+ struct task_struct *target)
{
- struct task_struct *tsk;
+ struct task_struct *parent =
+ !ptrace ? target->real_parent : target->parent;
+
+ return current == parent || (!(wo->wo_flags & __WNOTHREAD) &&
+ same_thread_group(current, parent));
+}
+
+/*
+ * Optimization for waiting on PIDTYPE_PID. No need to iterate through child
+ * and tracee lists to find the target task.
+ */
+static int do_wait_pid(struct wait_opts *wo)
+{
+ bool ptrace;
+ struct task_struct *target;
int retval;
- trace_sched_process_wait(wo->wo_pid);
+ ptrace = false;
+ target = pid_task(wo->wo_pid, PIDTYPE_TGID);
+ if (target && is_effectively_child(wo, ptrace, target)) {
+ retval = wait_consider_task(wo, ptrace, target);
+ if (retval)
+ return retval;
+ }
+
+ ptrace = true;
+ target = pid_task(wo->wo_pid, PIDTYPE_PID);
+ if (target && target->ptrace &&
+ is_effectively_child(wo, ptrace, target)) {
+ retval = wait_consider_task(wo, ptrace, target);
+ if (retval)
+ return retval;
+ }
+
+ return 0;
+}
+
+long __do_wait(struct wait_opts *wo)
+{
+ long retval;
- init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
- wo->child_wait.private = current;
- add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
-repeat:
/*
* If there is nothing that can match our criteria, just get out.
* We will clear ->notask_error to zero if we see any child that
*/
wo->notask_error = -ECHILD;
if ((wo->wo_type < PIDTYPE_MAX) &&
- (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))
+ (!wo->wo_pid || !pid_has_task(wo->wo_pid, wo->wo_type)))
goto notask;
- set_current_state(TASK_INTERRUPTIBLE);
read_lock(&tasklist_lock);
- tsk = current;
- do {
- retval = do_wait_thread(wo, tsk);
- if (retval)
- goto end;
- retval = ptrace_do_wait(wo, tsk);
+ if (wo->wo_type == PIDTYPE_PID) {
+ retval = do_wait_pid(wo);
if (retval)
- goto end;
+ return retval;
+ } else {
+ struct task_struct *tsk = current;
- if (wo->wo_flags & __WNOTHREAD)
- break;
- } while_each_thread(current, tsk);
+ do {
+ retval = do_wait_thread(wo, tsk);
+ if (retval)
+ return retval;
+
+ retval = ptrace_do_wait(wo, tsk);
+ if (retval)
+ return retval;
+
+ if (wo->wo_flags & __WNOTHREAD)
+ break;
+ } while_each_thread(current, tsk);
+ }
read_unlock(&tasklist_lock);
notask:
retval = wo->notask_error;
- if (!retval && !(wo->wo_flags & WNOHANG)) {
- retval = -ERESTARTSYS;
- if (!signal_pending(current)) {
- schedule();
- goto repeat;
- }
- }
-end:
+ if (!retval && !(wo->wo_flags & WNOHANG))
+ return -ERESTARTSYS;
+
+ return retval;
+}
+
+static long do_wait(struct wait_opts *wo)
+{
+ int retval;
+
+ trace_sched_process_wait(wo->wo_pid);
+
+ init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
+ wo->child_wait.private = current;
+ add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
+
+ do {
+ set_current_state(TASK_INTERRUPTIBLE);
+ retval = __do_wait(wo);
+ if (retval != -ERESTARTSYS)
+ break;
+ if (signal_pending(current))
+ break;
+ schedule();
+ } while (1);
+
__set_current_state(TASK_RUNNING);
remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
return retval;
}
-static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
- int options, struct rusage *ru)
+int kernel_waitid_prepare(struct wait_opts *wo, int which, pid_t upid,
+ struct waitid_info *infop, int options,
+ struct rusage *ru)
{
- struct wait_opts wo;
+ unsigned int f_flags = 0;
struct pid *pid = NULL;
enum pid_type type;
- long ret;
if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED|
__WNOTHREAD|__WCLONE|__WALL))
type = PIDTYPE_PID;
if (upid <= 0)
return -EINVAL;
+
+ pid = find_get_pid(upid);
break;
case P_PGID:
type = PIDTYPE_PGID;
- if (upid <= 0)
+ if (upid < 0)
+ return -EINVAL;
+
+ if (upid)
+ pid = find_get_pid(upid);
+ else
+ pid = get_task_pid(current, PIDTYPE_PGID);
+ break;
+ case P_PIDFD:
+ type = PIDTYPE_PID;
+ if (upid < 0)
return -EINVAL;
+
+ pid = pidfd_get_pid(upid, &f_flags);
+ if (IS_ERR(pid))
+ return PTR_ERR(pid);
+
break;
default:
return -EINVAL;
}
- if (type < PIDTYPE_MAX)
- pid = find_get_pid(upid);
+ wo->wo_type = type;
+ wo->wo_pid = pid;
+ wo->wo_flags = options;
+ wo->wo_info = infop;
+ wo->wo_rusage = ru;
+ if (f_flags & O_NONBLOCK)
+ wo->wo_flags |= WNOHANG;
+
+ return 0;
+}
+
+static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
+ int options, struct rusage *ru)
+{
+ struct wait_opts wo;
+ long ret;
+
+ ret = kernel_waitid_prepare(&wo, which, upid, infop, options, ru);
+ if (ret)
+ return ret;
- wo.wo_type = type;
- wo.wo_pid = pid;
- wo.wo_flags = options;
- wo.wo_info = infop;
- wo.wo_rusage = ru;
ret = do_wait(&wo);
+ if (!ret && !(options & WNOHANG) && (wo.wo_flags & WNOHANG))
+ ret = -EAGAIN;
- put_pid(pid);
+ put_pid(wo.wo_pid);
return ret;
}
if (!infop)
return err;
- if (!user_access_begin(infop, sizeof(*infop)))
+ if (!user_write_access_begin(infop, sizeof(*infop)))
return -EFAULT;
unsafe_put_user(signo, &infop->si_signo, Efault);
unsafe_put_user(info.pid, &infop->si_pid, Efault);
unsafe_put_user(info.uid, &infop->si_uid, Efault);
unsafe_put_user(info.status, &infop->si_status, Efault);
- user_access_end();
+ user_write_access_end();
return err;
Efault:
- user_access_end();
+ user_write_access_end();
return -EFAULT;
}
return ret;
}
+int kernel_wait(pid_t pid, int *stat)
+{
+ struct wait_opts wo = {
+ .wo_type = PIDTYPE_PID,
+ .wo_pid = find_get_pid(pid),
+ .wo_flags = WEXITED,
+ };
+ int ret;
+
+ ret = do_wait(&wo);
+ if (ret > 0 && wo.wo_stat)
+ *stat = wo.wo_stat;
+ put_pid(wo.wo_pid);
+ return ret;
+}
+
SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
int, options, struct rusage __user *, ru)
{
if (!infop)
return err;
- if (!user_access_begin(infop, sizeof(*infop)))
+ if (!user_write_access_begin(infop, sizeof(*infop)))
return -EFAULT;
unsafe_put_user(signo, &infop->si_signo, Efault);
unsafe_put_user(info.pid, &infop->si_pid, Efault);
unsafe_put_user(info.uid, &infop->si_uid, Efault);
unsafe_put_user(info.status, &infop->si_status, Efault);
- user_access_end();
+ user_write_access_end();
return err;
Efault:
- user_access_end();
+ user_write_access_end();
return -EFAULT;
}
#endif
-__weak void abort(void)
+/*
+ * This needs to be __function_aligned as GCC implicitly makes any
+ * implementation of abort() cold and drops alignment specified by
+ * -falign-functions=N.
+ *
+ * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c11
+ */
+__weak __function_aligned void abort(void)
{
BUG();
git.samba.org / sfrench / cifs-2.6.git / blobdiff