child->parent = new_parent;
}
- /*
- * Turn a tracing stop into a normal stop now, since with no tracer there
- * would be no way to wake it up with SIGCONT or SIGKILL. If there was a
- * signal sent that would resume the child, but didn't because it was in
- * TASK_TRACED, resume it now.
- * Requires that irqs be disabled.
- */
- static void ptrace_untrace(struct task_struct *child)
- {
- spin_lock(&child->sighand->siglock);
- if (task_is_traced(child)) {
- /*
- * If the group stop is completed or in progress,
- * this thread was already counted as stopped.
- */
- if (child->signal->flags & SIGNAL_STOP_STOPPED ||
- child->signal->group_stop_count)
- __set_task_state(child, TASK_STOPPED);
- else
- signal_wake_up(child, 1);
- }
- spin_unlock(&child->sighand->siglock);
- }
-
- /*
- * unptrace a task: move it back to its original parent and
- * remove it from the ptrace list.
+ /**
+ * __ptrace_unlink - unlink ptracee and restore its execution state
+ * @child: ptracee to be unlinked
*
- * Must be called with the tasklist lock write-held.
+ * Remove @child from the ptrace list, move it back to the original parent,
+ * and restore the execution state so that it conforms to the group stop
+ * state.
+ *
+ * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
+ * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
+ * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
+ * If the ptracer is exiting, the ptracee can be in any state.
+ *
+ * After detach, the ptracee should be in a state which conforms to the
+ * group stop. If the group is stopped or in the process of stopping, the
+ * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
+ * up from TASK_TRACED.
+ *
+ * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
+ * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
+ * to but in the opposite direction of what happens while attaching to a
+ * stopped task. However, in this direction, the intermediate RUNNING
+ * state is not hidden even from the current ptracer and if it immediately
+ * re-attaches and performs a WNOHANG wait(2), it may fail.
+ *
+ * CONTEXT:
+ * write_lock_irq(tasklist_lock)
*/
void __ptrace_unlink(struct task_struct *child)
{
child->parent = child->real_parent;
list_del_init(&child->ptrace_entry);
- if (task_is_traced(child))
- ptrace_untrace(child);
+ spin_lock(&child->sighand->siglock);
+
+ /*
+ * Reinstate GROUP_STOP_PENDING if group stop is in effect and
+ * @child isn't dead.
+ */
+ if (!(child->flags & PF_EXITING) &&
+ (child->signal->flags & SIGNAL_STOP_STOPPED ||
+ child->signal->group_stop_count))
+ child->group_stop |= GROUP_STOP_PENDING;
+
+ /*
+ * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
+ * @child in the butt. Note that @resume should be used iff @child
+ * is in TASK_TRACED; otherwise, we might unduly disrupt
+ * TASK_KILLABLE sleeps.
+ */
+ if (child->group_stop & GROUP_STOP_PENDING || task_is_traced(child))
+ signal_wake_up(child, task_is_traced(child));
+
+ spin_unlock(&child->sighand->siglock);
}
/*
*/
read_lock(&tasklist_lock);
if ((child->ptrace & PT_PTRACED) && child->parent == current) {
- ret = 0;
/*
* child->sighand can't be NULL, release_task()
* does ptrace_unlink() before __exit_signal().
*/
spin_lock_irq(&child->sighand->siglock);
- if (task_is_stopped(child))
- child->state = TASK_TRACED;
- else if (!task_is_traced(child) && !kill)
- ret = -ESRCH;
+ WARN_ON_ONCE(task_is_stopped(child));
+ if (task_is_traced(child) || kill)
+ ret = 0;
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);
return 0;
rcu_read_lock();
tcred = __task_cred(task);
- if ((cred->uid != tcred->euid ||
- cred->uid != tcred->suid ||
- cred->uid != tcred->uid ||
- cred->gid != tcred->egid ||
- cred->gid != tcred->sgid ||
- cred->gid != tcred->gid) &&
- !capable(CAP_SYS_PTRACE)) {
- rcu_read_unlock();
- return -EPERM;
- }
+ if (cred->user->user_ns == tcred->user->user_ns &&
+ (cred->uid == tcred->euid &&
+ cred->uid == tcred->suid &&
+ cred->uid == tcred->uid &&
+ cred->gid == tcred->egid &&
+ cred->gid == tcred->sgid &&
+ cred->gid == tcred->gid))
+ goto ok;
+ if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE))
+ goto ok;
+ rcu_read_unlock();
+ return -EPERM;
+ok:
rcu_read_unlock();
smp_rmb();
if (task->mm)
dumpable = get_dumpable(task->mm);
- if (!dumpable && !capable(CAP_SYS_PTRACE))
+ if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE))
return -EPERM;
return security_ptrace_access_check(task, mode);
static int ptrace_attach(struct task_struct *task)
{
+ bool wait_trap = false;
int retval;
audit_ptrace(task);
goto unlock_tasklist;
task->ptrace = PT_PTRACED;
- if (capable(CAP_SYS_PTRACE))
+ if (task_ns_capable(task, CAP_SYS_PTRACE))
task->ptrace |= PT_PTRACE_CAP;
__ptrace_link(task, current);
send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
+ spin_lock(&task->sighand->siglock);
+
+ /*
+ * If the task is already STOPPED, set GROUP_STOP_PENDING and
+ * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
+ * will be cleared if the child completes the transition or any
+ * event which clears the group stop states happens. We'll wait
+ * for the transition to complete before returning from this
+ * function.
+ *
+ * This hides STOPPED -> RUNNING -> TRACED transition from the
+ * attaching thread but a different thread in the same group can
+ * still observe the transient RUNNING state. IOW, if another
+ * thread's WNOHANG wait(2) on the stopped tracee races against
+ * ATTACH, the wait(2) may fail due to the transient RUNNING.
+ *
+ * The following task_is_stopped() test is safe as both transitions
+ * in and out of STOPPED are protected by siglock.
+ */
+ if (task_is_stopped(task)) {
+ task->group_stop |= GROUP_STOP_PENDING | GROUP_STOP_TRAPPING;
+ signal_wake_up(task, 1);
+ wait_trap = true;
+ }
+
+ spin_unlock(&task->sighand->siglock);
+
retval = 0;
unlock_tasklist:
write_unlock_irq(&tasklist_lock);
unlock_creds:
mutex_unlock(&task->signal->cred_guard_mutex);
out:
+ if (wait_trap)
+ wait_event(current->signal->wait_chldexit,
+ !(task->group_stop & GROUP_STOP_TRAPPING));
return retval;
}
if (child->ptrace) {
child->exit_code = data;
dead = __ptrace_detach(current, child);
- if (!child->exit_state)
- wake_up_state(child, TASK_TRACED | TASK_STOPPED);
}
write_unlock_irq(&tasklist_lock);
static int recalc_sigpending_tsk(struct task_struct *t)
{
- if (t->signal->group_stop_count > 0 ||
+ if ((t->group_stop & GROUP_STOP_PENDING) ||
PENDING(&t->pending, &t->blocked) ||
PENDING(&t->signal->shared_pending, &t->blocked)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
current->comm, current->pid, sig);
}
+ /**
+ * task_clear_group_stop_trapping - clear group stop trapping bit
+ * @task: target task
+ *
+ * If GROUP_STOP_TRAPPING is set, a ptracer is waiting for us. Clear it
+ * and wake up the ptracer. Note that we don't need any further locking.
+ * @task->siglock guarantees that @task->parent points to the ptracer.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+ static void task_clear_group_stop_trapping(struct task_struct *task)
+ {
+ if (unlikely(task->group_stop & GROUP_STOP_TRAPPING)) {
+ task->group_stop &= ~GROUP_STOP_TRAPPING;
+ __wake_up_sync(&task->parent->signal->wait_chldexit,
+ TASK_UNINTERRUPTIBLE, 1);
+ }
+ }
+
+ /**
+ * task_clear_group_stop_pending - clear pending group stop
+ * @task: target task
+ *
+ * Clear group stop states for @task.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+ void task_clear_group_stop_pending(struct task_struct *task)
+ {
+ task->group_stop &= ~(GROUP_STOP_PENDING | GROUP_STOP_CONSUME |
+ GROUP_STOP_DEQUEUED);
+ }
+
+ /**
+ * task_participate_group_stop - participate in a group stop
+ * @task: task participating in a group stop
+ *
+ * @task has GROUP_STOP_PENDING set and is participating in a group stop.
+ * Group stop states are cleared and the group stop count is consumed if
+ * %GROUP_STOP_CONSUME was set. If the consumption completes the group
+ * stop, the appropriate %SIGNAL_* flags are set.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if group stop completion should be notified to the parent, %false
+ * otherwise.
+ */
+ static bool task_participate_group_stop(struct task_struct *task)
+ {
+ struct signal_struct *sig = task->signal;
+ bool consume = task->group_stop & GROUP_STOP_CONSUME;
+
+ WARN_ON_ONCE(!(task->group_stop & GROUP_STOP_PENDING));
+
+ task_clear_group_stop_pending(task);
+
+ if (!consume)
+ return false;
+
+ if (!WARN_ON_ONCE(sig->group_stop_count == 0))
+ sig->group_stop_count--;
+
+ /*
+ * Tell the caller to notify completion iff we are entering into a
+ * fresh group stop. Read comment in do_signal_stop() for details.
+ */
+ if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
+ sig->flags = SIGNAL_STOP_STOPPED;
+ return true;
+ }
+ return false;
+ }
+
/*
* allocate a new signal queue record
* - this may be called without locks if and only if t == current, otherwise an
- * appopriate lock must be held to stop the target task from exiting
+ * appropriate lock must be held to stop the target task from exiting
*/
static struct sigqueue *
__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
return !tracehook_consider_fatal_signal(tsk, sig);
}
-
-/* Notify the system that a driver wants to block all signals for this
+/*
+ * Notify the system that a driver wants to block all signals for this
* process, and wants to be notified if any signals at all were to be
* sent/acted upon. If the notifier routine returns non-zero, then the
* signal will be acted upon after all. If the notifier routine returns 0,
* then then signal will be blocked. Only one block per process is
* allowed. priv is a pointer to private data that the notifier routine
- * can use to determine if the signal should be blocked or not. */
-
+ * can use to determine if the signal should be blocked or not.
+ */
void
block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
{
copy_siginfo(info, &first->info);
__sigqueue_free(first);
} else {
- /* Ok, it wasn't in the queue. This must be
- a fast-pathed signal or we must have been
- out of queue space. So zero out the info.
+ /*
+ * Ok, it wasn't in the queue. This must be
+ * a fast-pathed signal or we must have been
+ * out of queue space. So zero out the info.
*/
info->si_signo = sig;
info->si_errno = 0;
}
/*
- * Dequeue a signal and return the element to the caller, which is
+ * Dequeue a signal and return the element to the caller, which is
* expected to free it.
*
* All callers have to hold the siglock.
* itimers are process shared and we restart periodic
* itimers in the signal delivery path to prevent DoS
* attacks in the high resolution timer case. This is
- * compliant with the old way of self restarting
+ * compliant with the old way of self-restarting
* itimers, as the SIGALRM is a legacy signal and only
* queued once. Changing the restart behaviour to
* restart the timer in the signal dequeue path is
* is to alert stop-signal processing code when another
* processor has come along and cleared the flag.
*/
- tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
+ current->group_stop |= GROUP_STOP_DEQUEUED;
}
if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
/*
(!is_si_special(info) && SI_FROMUSER(info));
}
+/*
+ * called with RCU read lock from check_kill_permission()
+ */
+static int kill_ok_by_cred(struct task_struct *t)
+{
+ const struct cred *cred = current_cred();
+ const struct cred *tcred = __task_cred(t);
+
+ if (cred->user->user_ns == tcred->user->user_ns &&
+ (cred->euid == tcred->suid ||
+ cred->euid == tcred->uid ||
+ cred->uid == tcred->suid ||
+ cred->uid == tcred->uid))
+ return 1;
+
+ if (ns_capable(tcred->user->user_ns, CAP_KILL))
+ return 1;
+
+ return 0;
+}
+
/*
* Bad permissions for sending the signal
* - the caller must hold the RCU read lock
static int check_kill_permission(int sig, struct siginfo *info,
struct task_struct *t)
{
- const struct cred *cred, *tcred;
struct pid *sid;
int error;
if (error)
return error;
- cred = current_cred();
- tcred = __task_cred(t);
if (!same_thread_group(current, t) &&
- (cred->euid ^ tcred->suid) &&
- (cred->euid ^ tcred->uid) &&
- (cred->uid ^ tcred->suid) &&
- (cred->uid ^ tcred->uid) &&
- !capable(CAP_KILL)) {
+ !kill_ok_by_cred(t)) {
switch (sig) {
case SIGCONT:
sid = task_session(t);
} else if (sig == SIGCONT) {
unsigned int why;
/*
- * Remove all stop signals from all queues,
- * and wake all threads.
+ * Remove all stop signals from all queues, wake all threads.
*/
rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
t = p;
do {
- unsigned int state;
+ task_clear_group_stop_pending(t);
rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
- /*
- * If there is a handler for SIGCONT, we must make
- * sure that no thread returns to user mode before
- * we post the signal, in case it was the only
- * thread eligible to run the signal handler--then
- * it must not do anything between resuming and
- * running the handler. With the TIF_SIGPENDING
- * flag set, the thread will pause and acquire the
- * siglock that we hold now and until we've queued
- * the pending signal.
- *
- * Wake up the stopped thread _after_ setting
- * TIF_SIGPENDING
- */
- state = __TASK_STOPPED;
- if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
- set_tsk_thread_flag(t, TIF_SIGPENDING);
- state |= TASK_INTERRUPTIBLE;
- }
- wake_up_state(t, state);
+ wake_up_state(t, __TASK_STOPPED);
} while_each_thread(p, t);
/*
signal->flags = why | SIGNAL_STOP_CONTINUED;
signal->group_stop_count = 0;
signal->group_exit_code = 0;
- } else {
- /*
- * We are not stopped, but there could be a stop
- * signal in the middle of being processed after
- * being removed from the queue. Clear that too.
- */
- signal->flags &= ~SIGNAL_STOP_DEQUEUED;
}
}
signal->group_stop_count = 0;
t = p;
do {
+ task_clear_group_stop_pending(t);
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
} while_each_thread(p, t);
if (info == SEND_SIG_FORCED)
goto out_set;
- /* Real-time signals must be queued if sent by sigqueue, or
- some other real-time mechanism. It is implementation
- defined whether kill() does so. We attempt to do so, on
- the principle of least surprise, but since kill is not
- allowed to fail with EAGAIN when low on memory we just
- make sure at least one signal gets delivered and don't
- pass on the info struct. */
-
+ /*
+ * Real-time signals must be queued if sent by sigqueue, or
+ * some other real-time mechanism. It is implementation
+ * defined whether kill() does so. We attempt to do so, on
+ * the principle of least surprise, but since kill is not
+ * allowed to fail with EAGAIN when low on memory we just
+ * make sure at least one signal gets delivered and don't
+ * pass on the info struct.
+ */
if (sig < SIGRTMIN)
override_rlimit = (is_si_special(info) || info->si_code >= 0);
else
p->signal->group_stop_count = 0;
while_each_thread(p, t) {
+ task_clear_group_stop_pending(t);
count++;
/* Don't bother with already dead threads */
return error;
}
-int
-kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
{
int error;
rcu_read_lock();
* These are for backward compatibility with the rest of the kernel source.
*/
-int
-send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
/*
* Make sure legacy kernel users don't send in bad values
* These functions support sending signals using preallocated sigqueue
* structures. This is needed "because realtime applications cannot
* afford to lose notifications of asynchronous events, like timer
- * expirations or I/O completions". In the case of Posix Timers
+ * expirations or I/O completions". In the case of POSIX Timers
* we allocate the sigqueue structure from the timer_create. If this
* allocation fails we are able to report the failure to the application
* with an EAGAIN error.
return ret;
}
- static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
+ /**
+ * do_notify_parent_cldstop - notify parent of stopped/continued state change
+ * @tsk: task reporting the state change
+ * @for_ptracer: the notification is for ptracer
+ * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
+ *
+ * Notify @tsk's parent that the stopped/continued state has changed. If
+ * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
+ * If %true, @tsk reports to @tsk->parent which should be the ptracer.
+ *
+ * CONTEXT:
+ * Must be called with tasklist_lock at least read locked.
+ */
+ static void do_notify_parent_cldstop(struct task_struct *tsk,
+ bool for_ptracer, int why)
{
struct siginfo info;
unsigned long flags;
struct task_struct *parent;
struct sighand_struct *sighand;
- if (task_ptrace(tsk))
+ if (for_ptracer) {
parent = tsk->parent;
- else {
+ } else {
tsk = tsk->group_leader;
parent = tsk->real_parent;
}
info.si_signo = SIGCHLD;
info.si_errno = 0;
/*
- * see comment in do_notify_parent() abot the following 3 lines
+ * see comment in do_notify_parent() about the following 4 lines
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
}
/*
- * Return nonzero if there is a SIGKILL that should be waking us up.
+ * Return non-zero if there is a SIGKILL that should be waking us up.
* Called with the siglock held.
*/
static int sigkill_pending(struct task_struct *tsk)
sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
}
+ /*
+ * Test whether the target task of the usual cldstop notification - the
+ * real_parent of @child - is in the same group as the ptracer.
+ */
+ static bool real_parent_is_ptracer(struct task_struct *child)
+ {
+ return same_thread_group(child->parent, child->real_parent);
+ }
+
/*
* This must be called with current->sighand->siglock held.
*
* If we actually decide not to stop at all because the tracer
* is gone, we keep current->exit_code unless clear_code.
*/
- static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
+ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
__releases(¤t->sighand->siglock)
__acquires(¤t->sighand->siglock)
{
+ bool gstop_done = false;
+
if (arch_ptrace_stop_needed(exit_code, info)) {
/*
* The arch code has something special to do before a
}
/*
- * If there is a group stop in progress,
- * we must participate in the bookkeeping.
+ * 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.
*/
- if (current->signal->group_stop_count > 0)
- --current->signal->group_stop_count;
+ if (why == CLD_STOPPED && (current->group_stop & GROUP_STOP_PENDING))
+ gstop_done = task_participate_group_stop(current);
current->last_siginfo = info;
current->exit_code = exit_code;
- /* Let the debugger run. */
- __set_current_state(TASK_TRACED);
+ /*
+ * TRACED should be visible before TRAPPING is cleared; otherwise,
+ * the tracer might fail do_wait().
+ */
+ set_current_state(TASK_TRACED);
+
+ /*
+ * We're committing to trapping. Clearing GROUP_STOP_TRAPPING and
+ * transition to TASK_TRACED should be atomic with respect to
+ * siglock. This hsould be done after the arch hook as siglock is
+ * released and regrabbed across it.
+ */
+ task_clear_group_stop_trapping(current);
+
spin_unlock_irq(¤t->sighand->siglock);
read_lock(&tasklist_lock);
if (may_ptrace_stop()) {
- do_notify_parent_cldstop(current, CLD_TRAPPED);
+ /*
+ * Notify parents of the stop.
+ *
+ * While ptraced, there are two parents - the ptracer and
+ * the real_parent of the group_leader. The ptracer should
+ * know about every stop while the real parent is only
+ * interested in the completion of group stop. The states
+ * for the two don't interact with each other. Notify
+ * separately unless they're gonna be duplicates.
+ */
+ do_notify_parent_cldstop(current, true, why);
+ if (gstop_done && !real_parent_is_ptracer(current))
+ do_notify_parent_cldstop(current, false, why);
+
/*
* Don't want to allow preemption here, because
* sys_ptrace() needs this task to be inactive.
/*
* By the time we got the lock, our tracer went away.
* Don't drop the lock yet, another tracer may come.
+ *
+ * If @gstop_done, the ptracer went away between group stop
+ * completion and here. During detach, it would have set
+ * GROUP_STOP_PENDING on us and we'll re-enter TASK_STOPPED
+ * in do_signal_stop() on return, so notifying the real
+ * parent of the group stop completion is enough.
*/
+ if (gstop_done)
+ do_notify_parent_cldstop(current, false, why);
+
__set_current_state(TASK_RUNNING);
if (clear_code)
current->exit_code = 0;
/* Let the debugger run. */
spin_lock_irq(¤t->sighand->siglock);
- ptrace_stop(exit_code, 1, &info);
+ ptrace_stop(exit_code, CLD_TRAPPED, 1, &info);
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 nonzero if we've actually stopped and released the siglock.
+ * Returns non-zero if we've actually stopped and released the siglock.
* Returns zero if we didn't stop and still hold the siglock.
*/
static int do_signal_stop(int signr)
{
struct signal_struct *sig = current->signal;
- int notify;
- if (!sig->group_stop_count) {
+ if (!(current->group_stop & GROUP_STOP_PENDING)) {
+ unsigned int gstop = GROUP_STOP_PENDING | GROUP_STOP_CONSUME;
struct task_struct *t;
- if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
+ /* signr will be recorded in task->group_stop for retries */
+ WARN_ON_ONCE(signr & ~GROUP_STOP_SIGMASK);
+
+ if (!likely(current->group_stop & GROUP_STOP_DEQUEUED) ||
unlikely(signal_group_exit(sig)))
return 0;
/*
- * There is no group stop already in progress.
- * We must initiate one now.
+ * There is no group stop already in progress. We must
+ * initiate one now.
+ *
+ * While ptraced, a task may be resumed while group stop is
+ * still in effect and then receive a stop signal and
+ * initiate another group stop. This deviates from the
+ * usual behavior as two consecutive stop signals can't
+ * cause two group stops when !ptraced. That is why we
+ * also check !task_is_stopped(t) below.
+ *
+ * The condition can be distinguished by testing whether
+ * SIGNAL_STOP_STOPPED is already set. Don't generate
+ * group_exit_code in such case.
+ *
+ * This is not necessary for SIGNAL_STOP_CONTINUED because
+ * an intervening stop signal is required to cause two
+ * continued events regardless of ptrace.
*/
- sig->group_exit_code = signr;
+ if (!(sig->flags & SIGNAL_STOP_STOPPED))
+ sig->group_exit_code = signr;
+ else
+ WARN_ON_ONCE(!task_ptrace(current));
+ current->group_stop &= ~GROUP_STOP_SIGMASK;
+ current->group_stop |= signr | gstop;
sig->group_stop_count = 1;
- for (t = next_thread(current); t != current; t = next_thread(t))
+ for (t = next_thread(current); t != current;
+ t = next_thread(t)) {
+ t->group_stop &= ~GROUP_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_or_traced(t)) {
+ if (!(t->flags & PF_EXITING) && !task_is_stopped(t)) {
+ t->group_stop |= signr | gstop;
sig->group_stop_count++;
signal_wake_up(t, 0);
}
+ }
}
- /*
- * If there are no other threads in the group, or if there is
- * a group stop in progress and we are the last to stop, report
- * to the parent. When ptraced, every thread reports itself.
- */
- notify = sig->group_stop_count == 1 ? CLD_STOPPED : 0;
- notify = tracehook_notify_jctl(notify, CLD_STOPPED);
- /*
- * tracehook_notify_jctl() can drop and reacquire siglock, so
- * we keep ->group_stop_count != 0 before the call. If SIGCONT
- * or SIGKILL comes in between ->group_stop_count == 0.
- */
- if (sig->group_stop_count) {
- if (!--sig->group_stop_count)
- sig->flags = SIGNAL_STOP_STOPPED;
- current->exit_code = sig->group_exit_code;
+ retry:
+ if (likely(!task_ptrace(current))) {
+ int notify = 0;
+
+ /*
+ * If there are no other threads in the group, or if there
+ * is a group stop in progress and we are the last to stop,
+ * report to the parent.
+ */
+ if (task_participate_group_stop(current))
+ notify = CLD_STOPPED;
+
__set_current_state(TASK_STOPPED);
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ /*
+ * Notify the parent of the group stop completion. Because
+ * we're not holding either the siglock or tasklist_lock
+ * here, ptracer may attach inbetween; however, this is for
+ * group stop and should always be delivered to the real
+ * parent of the group leader. The new ptracer will get
+ * its notification when this task transitions into
+ * TASK_TRACED.
+ */
+ if (notify) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current, false, notify);
+ read_unlock(&tasklist_lock);
+ }
+
+ /* Now we don't run again until woken by SIGCONT or SIGKILL */
+ schedule();
+
+ spin_lock_irq(¤t->sighand->siglock);
+ } else {
+ ptrace_stop(current->group_stop & GROUP_STOP_SIGMASK,
+ CLD_STOPPED, 0, NULL);
+ current->exit_code = 0;
}
- spin_unlock_irq(¤t->sighand->siglock);
- if (notify) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, notify);
- read_unlock(&tasklist_lock);
+ /*
+ * GROUP_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->group_stop & GROUP_STOP_PENDING) {
+ WARN_ON_ONCE(!(current->group_stop & GROUP_STOP_SIGMASK));
+ goto retry;
}
- /* Now we don't run again until woken by SIGCONT or SIGKILL */
- do {
- schedule();
- } while (try_to_freeze());
+ /* PTRACE_ATTACH might have raced with task killing, clear trapping */
+ task_clear_group_stop_trapping(current);
+
+ spin_unlock_irq(¤t->sighand->siglock);
tracehook_finish_jctl();
- current->exit_code = 0;
return 1;
}
ptrace_signal_deliver(regs, cookie);
/* Let the debugger run. */
- ptrace_stop(signr, 0, info);
+ ptrace_stop(signr, CLD_TRAPPED, 0, info);
/* We're back. Did the debugger cancel the sig? */
signr = current->exit_code;
current->exit_code = 0;
- /* Update the siginfo structure if the signal has
- changed. If the debugger wanted something
- specific in the siginfo structure then it should
- have updated *info via PTRACE_SETSIGINFO. */
+ /*
+ * Update the siginfo structure if the signal has
+ * changed. If the debugger wanted something
+ * specific in the siginfo structure then it should
+ * have updated *info via PTRACE_SETSIGINFO.
+ */
if (signr != info->si_signo) {
info->si_signo = signr;
info->si_errno = 0;
* the CLD_ si_code into SIGNAL_CLD_MASK bits.
*/
if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
- int why = (signal->flags & SIGNAL_STOP_CONTINUED)
- ? CLD_CONTINUED : CLD_STOPPED;
+ struct task_struct *leader;
+ int why;
+
+ if (signal->flags & SIGNAL_CLD_CONTINUED)
+ why = CLD_CONTINUED;
+ else
+ why = CLD_STOPPED;
+
signal->flags &= ~SIGNAL_CLD_MASK;
- why = tracehook_notify_jctl(why, CLD_CONTINUED);
spin_unlock_irq(&sighand->siglock);
- if (why) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current->group_leader, why);
- read_unlock(&tasklist_lock);
- }
+ /*
+ * Notify the parent that we're continuing. This event is
+ * always per-process and doesn't make whole lot of sense
+ * for ptracers, who shouldn't consume the state via
+ * wait(2) either, but, for backward compatibility, notify
+ * the ptracer of the group leader too unless it's gonna be
+ * a duplicate.
+ */
+ read_lock(&tasklist_lock);
+
+ do_notify_parent_cldstop(current, false, why);
+
+ leader = current->group_leader;
+ if (task_ptrace(leader) && !real_parent_is_ptracer(leader))
+ do_notify_parent_cldstop(leader, true, why);
+
+ read_unlock(&tasklist_lock);
+
goto relock;
}
if (unlikely(signr != 0))
ka = return_ka;
else {
- if (unlikely(signal->group_stop_count > 0) &&
- do_signal_stop(0))
+ if (unlikely(current->group_stop &
+ GROUP_STOP_PENDING) && do_signal_stop(0))
goto relock;
signr = dequeue_signal(current, ¤t->blocked,
if (!signal_pending(tsk))
goto out;
- /* It could be that __group_complete_signal() choose us to
+ /*
+ * It could be that __group_complete_signal() choose us to
* notify about group-wide signal. Another thread should be
* woken now to take the signal since we will not.
*/
if (!signal_pending(t) && !(t->flags & PF_EXITING))
recalc_sigpending_and_wake(t);
- if (unlikely(tsk->signal->group_stop_count) &&
- !--tsk->signal->group_stop_count) {
- tsk->signal->flags = SIGNAL_STOP_STOPPED;
- group_stop = tracehook_notify_jctl(CLD_STOPPED, CLD_STOPPED);
- }
+ if (unlikely(tsk->group_stop & GROUP_STOP_PENDING) &&
+ task_participate_group_stop(tsk))
+ group_stop = CLD_STOPPED;
out:
spin_unlock_irq(&tsk->sighand->siglock);
+ /*
+ * If group stop has completed, deliver the notification. This
+ * should always go to the real parent of the group leader.
+ */
if (unlikely(group_stop)) {
read_lock(&tasklist_lock);
- do_notify_parent_cldstop(tsk, group_stop);
+ do_notify_parent_cldstop(tsk, false, group_stop);
read_unlock(&tasklist_lock);
}
}
* System call entry points.
*/
+/**
+ * sys_restart_syscall - restart a system call
+ */
SYSCALL_DEFINE0(restart_syscall)
{
struct restart_block *restart = ¤t_thread_info()->restart_block;
return error;
}
+/**
+ * sys_rt_sigprocmask - change the list of currently blocked signals
+ * @how: whether to add, remove, or set signals
+ * @set: stores pending signals
+ * @oset: previous value of signal mask if non-null
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
sigset_t __user *, oset, size_t, sigsetsize)
{
out:
return error;
-}
+}
+/**
+ * sys_rt_sigpending - examine a pending signal that has been raised
+ * while blocked
+ * @set: stores pending signals
+ * @sigsetsize: size of sigset_t type or larger
+ */
SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
{
return do_sigpending(set, sigsetsize);
err |= __put_user(from->si_trapno, &to->si_trapno);
#endif
#ifdef BUS_MCEERR_AO
- /*
+ /*
* Other callers might not initialize the si_lsb field,
- * so check explicitely for the right codes here.
+ * so check explicitly for the right codes here.
*/
if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
#endif
+/**
+ * sys_rt_sigtimedwait - synchronously wait for queued signals specified
+ * in @uthese
+ * @uthese: queued signals to wait for
+ * @uinfo: if non-null, the signal's siginfo is returned here
+ * @uts: upper bound on process time suspension
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
siginfo_t __user *, uinfo, const struct timespec __user *, uts,
size_t, sigsetsize)
if (copy_from_user(&these, uthese, sizeof(these)))
return -EFAULT;
-
+
/*
* Invert the set of allowed signals to get those we
* want to block.
+ (ts.tv_sec || ts.tv_nsec));
if (timeout) {
- /* None ready -- temporarily unblock those we're
+ /*
+ * None ready -- temporarily unblock those we're
* interested while we are sleeping in so that we'll
- * be awakened when they arrive. */
+ * be awakened when they arrive.
+ */
current->real_blocked = current->blocked;
sigandsets(¤t->blocked, ¤t->blocked, &these);
recalc_sigpending();
return ret;
}
+/**
+ * sys_kill - send a signal to a process
+ * @pid: the PID of the process
+ * @sig: signal to be sent
+ */
SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
struct siginfo info;
return do_tkill(tgid, pid, sig);
}
-/*
+/**
+ * sys_tkill - send signal to one specific task
+ * @pid: the PID of the task
+ * @sig: signal to be sent
+ *
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
return do_tkill(0, pid, sig);
}
+/**
+ * sys_rt_sigqueueinfo - send signal information to a signal
+ * @pid: the PID of the thread
+ * @sig: signal to be sent
+ * @uinfo: signal info to be sent
+ */
SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
siginfo_t __user *, uinfo)
{
/* Not even root can pretend to send signals from the kernel.
* Nor can they impersonate a kill()/tgkill(), which adds source info.
*/
- if (info.si_code != SI_QUEUE) {
+ if (info.si_code >= 0 || info.si_code == SI_TKILL) {
/* We used to allow any < 0 si_code */
WARN_ON_ONCE(info.si_code < 0);
return -EPERM;
/* Not even root can pretend to send signals from the kernel.
* Nor can they impersonate a kill()/tgkill(), which adds source info.
*/
- if (info->si_code != SI_QUEUE) {
+ if (info->si_code >= 0 || info->si_code == SI_TKILL) {
/* We used to allow any < 0 si_code */
WARN_ON_ONCE(info->si_code < 0);
return -EPERM;
error = -EINVAL;
/*
- *
- * Note - this code used to test ss_flags incorrectly
+ * Note - this code used to test ss_flags incorrectly:
* old code may have been written using ss_flags==0
* to mean ss_flags==SS_ONSTACK (as this was the only
* way that worked) - this fix preserves that older
- * mechanism
+ * mechanism.
*/
if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
goto out;
#ifdef __ARCH_WANT_SYS_SIGPENDING
+/**
+ * sys_sigpending - examine pending signals
+ * @set: where mask of pending signal is returned
+ */
SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
{
return do_sigpending(set, sizeof(*set));
#endif
#ifdef __ARCH_WANT_SYS_SIGPROCMASK
-/* Some platforms have their own version with special arguments others
- support only sys_rt_sigprocmask. */
+/**
+ * sys_sigprocmask - examine and change blocked signals
+ * @how: whether to add, remove, or set signals
+ * @set: signals to add or remove (if non-null)
+ * @oset: previous value of signal mask if non-null
+ *
+ * Some platforms have their own version with special arguments;
+ * others support only sys_rt_sigprocmask.
+ */
SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
old_sigset_t __user *, oset)
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
#ifdef __ARCH_WANT_SYS_RT_SIGACTION
+/**
+ * sys_rt_sigaction - alter an action taken by a process
+ * @sig: signal to be sent
+ * @act: the thread group ID of the thread
+ * @oact: the PID of the thread
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE4(rt_sigaction, int, sig,
const struct sigaction __user *, act,
struct sigaction __user *, oact,
#endif
#ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
+/**
+ * sys_rt_sigsuspend - replace the signal mask for a value with the
+ * @unewset value until a signal is received
+ * @unewset: new signal mask value
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
{
sigset_t newset;
git.openpandora.org / pandora-kernel.git / commitdiff