static int recalc_sigpending_tsk(struct task_struct *t)
{
- if ((t->jobctl & JOBCTL_STOP_PENDING) ||
+ if ((t->jobctl & JOBCTL_PENDING_MASK) ||
PENDING(&t->pending, &t->blocked) ||
PENDING(&t->signal->shared_pending, &t->blocked)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
void recalc_sigpending(void)
{
- if (unlikely(tracehook_force_sigpending()))
- set_thread_flag(TIF_SIGPENDING);
- else if (!recalc_sigpending_tsk(current) && !freezing(current))
+ if (!recalc_sigpending_tsk(current) && !freezing(current))
clear_thread_flag(TIF_SIGPENDING);
}
current->comm, current->pid, sig);
}
+/**
+ * task_set_jobctl_pending - set jobctl pending bits
+ * @task: target task
+ * @mask: pending bits to set
+ *
+ * Clear @mask from @task->jobctl. @mask must be subset of
+ * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
+ * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
+ * cleared. If @task is already being killed or exiting, this function
+ * becomes noop.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if @mask is set, %false if made noop because @task was dying.
+ */
+bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask)
+{
+ BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
+ JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
+ BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
+
+ if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
+ return false;
+
+ if (mask & JOBCTL_STOP_SIGMASK)
+ task->jobctl &= ~JOBCTL_STOP_SIGMASK;
+
+ task->jobctl |= mask;
+ return true;
+}
+
/**
* task_clear_jobctl_trapping - clear jobctl trapping bit
* @task: target task
* CONTEXT:
* Must be called with @task->sighand->siglock held.
*/
-static void task_clear_jobctl_trapping(struct task_struct *task)
+void task_clear_jobctl_trapping(struct task_struct *task)
{
if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
task->jobctl &= ~JOBCTL_TRAPPING;
- __wake_up_sync_key(&task->parent->signal->wait_chldexit,
- TASK_UNINTERRUPTIBLE, 1, task);
+ wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
}
}
/**
- * task_clear_jobctl_stop_pending - clear pending group stop
+ * task_clear_jobctl_pending - clear jobctl pending bits
* @task: target task
+ * @mask: pending bits to clear
+ *
+ * Clear @mask from @task->jobctl. @mask must be subset of
+ * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
+ * STOP bits are cleared together.
*
- * Clear group stop states for @task.
+ * If clearing of @mask leaves no stop or trap pending, this function calls
+ * task_clear_jobctl_trapping().
*
* CONTEXT:
* Must be called with @task->sighand->siglock held.
*/
-void task_clear_jobctl_stop_pending(struct task_struct *task)
+void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask)
{
- task->jobctl &= ~(JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME |
- JOBCTL_STOP_DEQUEUED);
+ BUG_ON(mask & ~JOBCTL_PENDING_MASK);
+
+ if (mask & JOBCTL_STOP_PENDING)
+ mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
+
+ task->jobctl &= ~mask;
+
+ if (!(task->jobctl & JOBCTL_PENDING_MASK))
+ task_clear_jobctl_trapping(task);
}
/**
WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
- task_clear_jobctl_stop_pending(task);
+ task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
if (!consume)
return false;
rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
t = p;
do {
- task_clear_jobctl_stop_pending(t);
+ task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
wake_up_state(t, __TASK_STOPPED);
} while_each_thread(p, t);
signal->group_stop_count = 0;
t = p;
do {
- task_clear_jobctl_stop_pending(t);
+ task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
} while_each_thread(p, t);
p->signal->group_stop_count = 0;
while_each_thread(p, t) {
- task_clear_jobctl_stop_pending(t);
+ task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
count++;
/* Don't bother with already dead threads */
}
/*
- * If @why is CLD_STOPPED, we're trapping to participate in a group
- * stop. Do the bookkeeping. Note that if SIGCONT was delievered
- * while siglock was released for the arch hook, PENDING could be
- * clear now. We act as if SIGCONT is received after TASK_TRACED
- * is entered - ignore it.
+ * We're committing to trapping. TRACED should be visible before
+ * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
+ * Also, transition to TRACED and updates to ->jobctl should be
+ * atomic with respect to siglock and should be done after the arch
+ * hook as siglock is released and regrabbed across it.
*/
- if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
- gstop_done = task_participate_group_stop(current);
+ set_current_state(TASK_TRACED);
current->last_siginfo = info;
current->exit_code = exit_code;
/*
- * TRACED should be visible before TRAPPING is cleared; otherwise,
- * the tracer might fail do_wait().
+ * If @why is CLD_STOPPED, we're trapping to participate in a group
+ * stop. Do the bookkeeping. Note that if SIGCONT was delievered
+ * across siglock relocks since INTERRUPT was scheduled, PENDING
+ * could be clear now. We act as if SIGCONT is received after
+ * TASK_TRACED is entered - ignore it.
*/
- set_current_state(TASK_TRACED);
+ if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
+ gstop_done = task_participate_group_stop(current);
- /*
- * We're committing to trapping. Clearing JOBCTL_TRAPPING and
- * transition to TASK_TRACED should be atomic with respect to
- * siglock. This should be done after the arch hook as siglock is
- * released and regrabbed across it.
- */
+ /* any trap clears pending STOP trap */
+ task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
+
+ /* entering a trap, clear TRAPPING */
task_clear_jobctl_trapping(current);
spin_unlock_irq(¤t->sighand->siglock);
recalc_sigpending_tsk(current);
}
-void ptrace_notify(int exit_code)
+static void ptrace_do_notify(int signr, int exit_code, int why)
{
siginfo_t info;
- BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
-
memset(&info, 0, sizeof info);
- info.si_signo = SIGTRAP;
+ info.si_signo = signr;
info.si_code = exit_code;
info.si_pid = task_pid_vnr(current);
info.si_uid = current_uid();
/* Let the debugger run. */
+ ptrace_stop(exit_code, why, 1, &info);
+}
+
+void ptrace_notify(int exit_code)
+{
+ BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+
spin_lock_irq(¤t->sighand->siglock);
- ptrace_stop(exit_code, CLD_TRAPPED, 1, &info);
+ ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
spin_unlock_irq(¤t->sighand->siglock);
}
-/*
- * This performs the stopping for SIGSTOP and other stop signals.
- * We have to stop all threads in the thread group.
- * Returns non-zero if we've actually stopped and released the siglock.
- * Returns zero if we didn't stop and still hold the siglock.
+/**
+ * do_signal_stop - handle group stop for SIGSTOP and other stop signals
+ * @signr: signr causing group stop if initiating
+ *
+ * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
+ * and participate in it. If already set, participate in the existing
+ * group stop. If participated in a group stop (and thus slept), %true is
+ * returned with siglock released.
+ *
+ * If ptraced, this function doesn't handle stop itself. Instead,
+ * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
+ * untouched. The caller must ensure that INTERRUPT trap handling takes
+ * places afterwards.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which is released
+ * on %true return.
+ *
+ * RETURNS:
+ * %false if group stop is already cancelled or ptrace trap is scheduled.
+ * %true if participated in group stop.
*/
-static int do_signal_stop(int signr)
+static bool do_signal_stop(int signr)
+ __releases(¤t->sighand->siglock)
{
struct signal_struct *sig = current->signal;
if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
unlikely(signal_group_exit(sig)))
- return 0;
+ return false;
/*
* There is no group stop already in progress. We must
* initiate one now.
else
WARN_ON_ONCE(!task_ptrace(current));
- current->jobctl &= ~JOBCTL_STOP_SIGMASK;
- current->jobctl |= signr | gstop;
- sig->group_stop_count = 1;
+ sig->group_stop_count = 0;
+
+ if (task_set_jobctl_pending(current, signr | gstop))
+ sig->group_stop_count++;
+
for (t = next_thread(current); t != current;
t = next_thread(t)) {
- t->jobctl &= ~JOBCTL_STOP_SIGMASK;
/*
* Setting state to TASK_STOPPED for a group
* stop is always done with the siglock held,
* so this check has no races.
*/
- if (!(t->flags & PF_EXITING) && !task_is_stopped(t)) {
- t->jobctl |= signr | gstop;
+ if (!task_is_stopped(t) &&
+ task_set_jobctl_pending(t, signr | gstop)) {
sig->group_stop_count++;
signal_wake_up(t, 0);
}
}
}
-retry:
+
if (likely(!task_ptrace(current))) {
int notify = 0;
/* Now we don't run again until woken by SIGCONT or SIGKILL */
schedule();
-
- spin_lock_irq(¤t->sighand->siglock);
+ return true;
} else {
- ptrace_stop(current->jobctl & JOBCTL_STOP_SIGMASK,
- CLD_STOPPED, 0, NULL);
- current->exit_code = 0;
+ /*
+ * While ptraced, group stop is handled by STOP trap.
+ * Schedule it and let the caller deal with it.
+ */
+ task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
+ return false;
}
+}
- /*
- * JOBCTL_STOP_PENDING could be set if another group stop has
- * started since being woken up or ptrace wants us to transit
- * between TASK_STOPPED and TRACED. Retry group stop.
- */
- if (current->jobctl & JOBCTL_STOP_PENDING) {
- WARN_ON_ONCE(!(current->jobctl & JOBCTL_STOP_SIGMASK));
- goto retry;
+/**
+ * do_jobctl_trap - take care of ptrace jobctl traps
+ *
+ * When PT_SEIZED, it's used for both group stop and explicit
+ * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
+ * accompanying siginfo. If stopped, lower eight bits of exit_code contain
+ * the stop signal; otherwise, %SIGTRAP.
+ *
+ * When !PT_SEIZED, it's used only for group stop trap with stop signal
+ * number as exit_code and no siginfo.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which may be
+ * released and re-acquired before returning with intervening sleep.
+ */
+static void do_jobctl_trap(void)
+{
+ struct signal_struct *signal = current->signal;
+ int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
+
+ if (current->ptrace & PT_SEIZED) {
+ if (!signal->group_stop_count &&
+ !(signal->flags & SIGNAL_STOP_STOPPED))
+ signr = SIGTRAP;
+ WARN_ON_ONCE(!signr);
+ ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
+ CLD_STOPPED);
+ } else {
+ WARN_ON_ONCE(!signr);
+ ptrace_stop(signr, CLD_STOPPED, 0, NULL);
+ current->exit_code = 0;
}
-
- /* PTRACE_ATTACH might have raced with task killing, clear trapping */
- task_clear_jobctl_trapping(current);
-
- spin_unlock_irq(¤t->sighand->siglock);
-
- tracehook_finish_jctl();
-
- return 1;
}
static int ptrace_signal(int signr, siginfo_t *info,
for (;;) {
struct k_sigaction *ka;
- /*
- * Tracing can induce an artificial signal and choose sigaction.
- * The return value in @signr determines the default action,
- * but @info->si_signo is the signal number we will report.
- */
- signr = tracehook_get_signal(current, regs, info, return_ka);
- if (unlikely(signr < 0))
+
+ if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
+ do_signal_stop(0))
goto relock;
- if (unlikely(signr != 0))
- ka = return_ka;
- else {
- if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
- do_signal_stop(0))
- goto relock;
- signr = dequeue_signal(current, ¤t->blocked,
- info);
+ if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
+ do_jobctl_trap();
+ spin_unlock_irq(&sighand->siglock);
+ goto relock;
+ }
- if (!signr)
- break; /* will return 0 */
+ signr = dequeue_signal(current, ¤t->blocked, info);
- if (signr != SIGKILL) {
- signr = ptrace_signal(signr, info,
- regs, cookie);
- if (!signr)
- continue;
- }
+ if (!signr)
+ break; /* will return 0 */
- ka = &sighand->action[signr-1];
+ if (signr != SIGKILL) {
+ signr = ptrace_signal(signr, info,
+ regs, cookie);
+ if (!signr)
+ continue;
}
+ ka = &sighand->action[signr-1];
+
/* Trace actually delivered signals. */
trace_signal_deliver(signr, info, ka);
projects / mirror_ubuntu-zesty-kernel.git / blobdiff