*/
rcu_read_lock();
ucounts = task_ucounts(t);
- sigpending = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1);
- switch (sigpending) {
- case 1:
- if (likely(get_ucounts(ucounts)))
- break;
- fallthrough;
- case LONG_MAX:
- /*
- * we need to decrease the ucount in the userns tree on any
- * failure to avoid counts leaking.
- */
- dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1);
- rcu_read_unlock();
- return NULL;
- }
+ sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
rcu_read_unlock();
+ if (!sigpending)
+ return NULL;
if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
}
if (unlikely(q == NULL)) {
- if (dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1))
- put_ucounts(ucounts);
+ dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
} else {
INIT_LIST_HEAD(&q->list);
q->flags = sigqueue_flags;
{
if (q->flags & SIGQUEUE_PREALLOC)
return;
- if (q->ucounts && dec_rlimit_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING, 1)) {
- put_ucounts(q->ucounts);
+ if (q->ucounts) {
+ dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING);
q->ucounts = NULL;
}
kmem_cache_free(sigqueue_cachep, q);
return ret;
}
+enum sig_handler {
+ HANDLER_CURRENT, /* If reachable use the current handler */
+ HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
+ HANDLER_EXIT, /* Only visible as the process exit code */
+};
+
/*
* Force a signal that the process can't ignore: if necessary
* we unblock the signal and change any SIG_IGN to SIG_DFL.
* that is why we also clear SIGNAL_UNKILLABLE.
*/
static int
-force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t, bool sigdfl)
+force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
+ enum sig_handler handler)
{
unsigned long int flags;
int ret, blocked, ignored;
struct k_sigaction *action;
int sig = info->si_signo;
+ /*
+ * On some archs, PREEMPT_RT has to delay sending a signal from a trap
+ * since it can not enable preemption, and the signal code's spin_locks
+ * turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME which will
+ * send the signal on exit of the trap.
+ */
+#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
+ if (in_atomic()) {
+ struct task_struct *t = current;
+
+ if (WARN_ON_ONCE(t->forced_info.si_signo))
+ return 0;
+
+ if (is_si_special(info)) {
+ WARN_ON_ONCE(info != SEND_SIG_PRIV);
+ t->forced_info.si_signo = info->si_signo;
+ t->forced_info.si_errno = 0;
+ t->forced_info.si_code = SI_KERNEL;
+ t->forced_info.si_pid = 0;
+ t->forced_info.si_uid = 0;
+ } else {
+ t->forced_info = *info;
+ }
+
+ set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
+ return 0;
+ }
+#endif
spin_lock_irqsave(&t->sighand->siglock, flags);
action = &t->sighand->action[sig-1];
ignored = action->sa.sa_handler == SIG_IGN;
blocked = sigismember(&t->blocked, sig);
- if (blocked || ignored || sigdfl) {
+ if (blocked || ignored || (handler != HANDLER_CURRENT)) {
action->sa.sa_handler = SIG_DFL;
+ if (handler == HANDLER_EXIT)
+ action->sa.sa_flags |= SA_IMMUTABLE;
if (blocked) {
sigdelset(&t->blocked, sig);
recalc_sigpending_and_wake(t);
}
/*
* Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
- * debugging to leave init killable.
+ * debugging to leave init killable. But HANDLER_EXIT is always fatal.
*/
- if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
+ if (action->sa.sa_handler == SIG_DFL &&
+ (!t->ptrace || (handler == HANDLER_EXIT)))
t->signal->flags &= ~SIGNAL_UNKILLABLE;
ret = send_signal(sig, info, t, PIDTYPE_PID);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
int force_sig_info(struct kernel_siginfo *info)
{
- return force_sig_info_to_task(info, current, false);
+ return force_sig_info_to_task(info, current, HANDLER_CURRENT);
}
/*
}
EXPORT_SYMBOL(force_sig);
+void force_fatal_sig(int sig)
+{
+ struct kernel_siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = sig;
+ info.si_errno = 0;
+ info.si_code = SI_KERNEL;
+ info.si_pid = 0;
+ info.si_uid = 0;
+ force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
+}
+
+void force_exit_sig(int sig)
+{
+ struct kernel_siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = sig;
+ info.si_errno = 0;
+ info.si_code = SI_KERNEL;
+ info.si_pid = 0;
+ info.si_uid = 0;
+ force_sig_info_to_task(&info, current, HANDLER_EXIT);
+}
+
/*
* When things go south during signal handling, we
* will force a SIGSEGV. And if the signal that caused
*/
void force_sigsegv(int sig)
{
- struct task_struct *p = current;
-
- if (sig == SIGSEGV) {
- unsigned long flags;
- spin_lock_irqsave(&p->sighand->siglock, flags);
- p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- }
- force_sig(SIGSEGV);
+ if (sig == SIGSEGV)
+ force_fatal_sig(SIGSEGV);
+ else
+ force_sig(SIGSEGV);
}
int force_sig_fault_to_task(int sig, int code, void __user *addr
info.si_flags = flags;
info.si_isr = isr;
#endif
- return force_sig_info_to_task(&info, t, false);
+ return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
}
int force_sig_fault(int sig, int code, void __user *addr
}
#endif
-int force_sig_perf(void __user *addr, u32 type, u64 sig_data)
+int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
{
struct kernel_siginfo info;
info.si_perf_data = sig_data;
info.si_perf_type = type;
- return force_sig_info(&info);
+ /*
+ * Signals generated by perf events should not terminate the whole
+ * process if SIGTRAP is blocked, however, delivering the signal
+ * asynchronously is better than not delivering at all. But tell user
+ * space if the signal was asynchronous, so it can clearly be
+ * distinguished from normal synchronous ones.
+ */
+ info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
+ TRAP_PERF_FLAG_ASYNC :
+ 0;
+
+ return send_sig_info(info.si_signo, &info, current);
}
/**
info.si_errno = reason;
info.si_arch = syscall_get_arch(current);
info.si_syscall = syscall;
- return force_sig_info_to_task(&info, current, force_coredump);
+ return force_sig_info_to_task(&info, current,
+ force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
}
/* For the crazy architectures that include trap information in
bool autoreap = false;
u64 utime, stime;
- BUG_ON(sig == -1);
+ WARN_ON_ONCE(sig == -1);
- /* do_notify_parent_cldstop should have been called instead. */
- BUG_ON(task_is_stopped_or_traced(tsk));
+ /* do_notify_parent_cldstop should have been called instead. */
+ WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
- BUG_ON(!tsk->ptrace &&
+ WARN_ON_ONCE(!tsk->ptrace &&
(tsk->group_leader != tsk || !thread_group_empty(tsk)));
/* Wake up all pidfd waiters */
return true;
}
-/*
- * Return non-zero if there is a SIGKILL that should be waking us up.
- * Called with the siglock held.
- */
-static bool sigkill_pending(struct task_struct *tsk)
-{
- return sigismember(&tsk->pending.signal, SIGKILL) ||
- sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
-}
/*
* This must be called with current->sighand->siglock held.
* calling arch_ptrace_stop, so we must release it now.
* To preserve proper semantics, we must do this before
* any signal bookkeeping like checking group_stop_count.
- * Meanwhile, a SIGKILL could come in before we retake the
- * siglock. That must prevent us from sleeping in TASK_TRACED.
- * So after regaining the lock, we must check for SIGKILL.
*/
spin_unlock_irq(¤t->sighand->siglock);
arch_ptrace_stop(exit_code, info);
spin_lock_irq(¤t->sighand->siglock);
- if (sigkill_pending(current))
- return;
}
+ /*
+ * schedule() will not sleep if there is a pending signal that
+ * can awaken the task.
+ */
set_special_state(TASK_TRACED);
/*
if (gstop_done && ptrace_reparented(current))
do_notify_parent_cldstop(current, false, why);
- /*
- * Don't want to allow preemption here, because
- * sys_ptrace() needs this task to be inactive.
- *
- * XXX: implement read_unlock_no_resched().
- */
- preempt_disable();
read_unlock(&tasklist_lock);
cgroup_enter_frozen();
- preempt_enable_no_resched();
freezable_schedule();
cgroup_leave_frozen(true);
} else {
goto relock;
}
- /* Has this task already been marked for death? */
- if (signal_group_exit(signal)) {
- ksig->info.si_signo = signr = SIGKILL;
- sigdelset(¤t->pending.signal, SIGKILL);
- trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
- &sighand->action[SIGKILL - 1]);
- recalc_sigpending();
- goto fatal;
- }
-
for (;;) {
struct k_sigaction *ka;
+ /* Has this task already been marked for death? */
+ if (signal_group_exit(signal)) {
+ ksig->info.si_signo = signr = SIGKILL;
+ sigdelset(¤t->pending.signal, SIGKILL);
+ trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
+ &sighand->action[SIGKILL - 1]);
+ recalc_sigpending();
+ goto fatal;
+ }
+
if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
do_signal_stop(0))
goto relock;
if (!signr)
break; /* will return 0 */
- if (unlikely(current->ptrace) && signr != SIGKILL) {
+ if (unlikely(current->ptrace) && (signr != SIGKILL) &&
+ !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
signr = ptrace_signal(signr, &ksig->info);
if (!signr)
continue;
to->si_addr = ptr_to_compat(from->si_addr);
to->si_perf_data = from->si_perf_data;
to->si_perf_type = from->si_perf_type;
+ to->si_perf_flags = from->si_perf_flags;
break;
case SIL_CHLD:
to->si_pid = from->si_pid;
to->si_addr = compat_ptr(from->si_addr);
to->si_perf_data = from->si_perf_data;
to->si_perf_type = from->si_perf_type;
+ to->si_perf_flags = from->si_perf_flags;
break;
case SIL_CHLD:
to->si_pid = from->si_pid;
k = &p->sighand->action[sig-1];
spin_lock_irq(&p->sighand->siglock);
+ if (k->sa.sa_flags & SA_IMMUTABLE) {
+ spin_unlock_irq(&p->sighand->siglock);
+ return -EINVAL;
+ }
if (oact)
*oact = *k;
CHECK_OFFSET(si_pkey);
CHECK_OFFSET(si_perf_data);
CHECK_OFFSET(si_perf_type);
+ CHECK_OFFSET(si_perf_flags);
/* sigpoll */
CHECK_OFFSET(si_band);
projects / platform / kernel / linux-rpi.git / blobdiff