Merge branch 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc
* 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc: (41 commits)
signal: trivial, fix the "timespec declared inside parameter list" warning
job control: reorganize wait_task_stopped()
ptrace: fix signal->wait_chldexit usage in task_clear_group_stop_trapping()
signal: sys_sigprocmask() needs retarget_shared_pending()
signal: cleanup sys_sigprocmask()
signal: rename signandsets() to sigandnsets()
signal: do_sigtimedwait() needs retarget_shared_pending()
signal: introduce do_sigtimedwait() to factor out compat/native code
signal: sys_rt_sigtimedwait: simplify the timeout logic
signal: cleanup sys_rt_sigprocmask()
x86: signal: sys_rt_sigreturn() should use set_current_blocked()
x86: signal: handle_signal() should use set_current_blocked()
signal: sigprocmask() should do retarget_shared_pending()
signal: sigprocmask: narrow the scope of ->siglock
signal: retarget_shared_pending: optimize while_each_thread() loop
signal: retarget_shared_pending: consider shared/unblocked signals only
signal: introduce retarget_shared_pending()
ptrace: ptrace_check_attach() should not do s/STOPPED/TRACED/
signal: Turn SIGNAL_STOP_DEQUEUED into GROUP_STOP_DEQUEUED
signal: do_signal_stop: Remove the unneeded task_clear_group_stop_pending()
...
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 4fd173c..40a2493 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -601,10 +601,7 @@
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
- spin_lock_irq(¤t->sighand->siglock);
- current->blocked = set;
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
+ set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
goto badframe;
@@ -682,6 +679,7 @@
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
sigset_t *oldset, struct pt_regs *regs)
{
+ sigset_t blocked;
int ret;
/* Are we from a system call? */
@@ -741,12 +739,10 @@
*/
regs->flags &= ~X86_EFLAGS_TF;
- spin_lock_irq(¤t->sighand->siglock);
- sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
+ sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
- sigaddset(¤t->blocked, sig);
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
+ sigaddset(&blocked, sig);
+ set_current_blocked(&blocked);
tracehook_signal_handler(sig, info, ka, regs,
test_thread_flag(TIF_SINGLESTEP));
diff --git a/fs/exec.c b/fs/exec.c
index 5e62d26..8328beb 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1659,6 +1659,7 @@
t = start;
do {
+ task_clear_group_stop_pending(t);
if (t != current && t->mm) {
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 12211e1..885c4f2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -653,9 +653,8 @@
* Bits in flags field of signal_struct.
*/
#define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */
-#define SIGNAL_STOP_DEQUEUED 0x00000002 /* stop signal dequeued */
-#define SIGNAL_STOP_CONTINUED 0x00000004 /* SIGCONT since WCONTINUED reap */
-#define SIGNAL_GROUP_EXIT 0x00000008 /* group exit in progress */
+#define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */
+#define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */
/*
* Pending notifications to parent.
*/
@@ -1251,6 +1250,7 @@
int exit_state;
int exit_code, exit_signal;
int pdeath_signal; /* The signal sent when the parent dies */
+ unsigned int group_stop; /* GROUP_STOP_*, siglock protected */
/* ??? */
unsigned int personality;
unsigned did_exec:1;
@@ -1771,6 +1771,17 @@
#define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
#define used_math() tsk_used_math(current)
+/*
+ * task->group_stop flags
+ */
+#define GROUP_STOP_SIGMASK 0xffff /* signr of the last group stop */
+#define GROUP_STOP_PENDING (1 << 16) /* task should stop for group stop */
+#define GROUP_STOP_CONSUME (1 << 17) /* consume group stop count */
+#define GROUP_STOP_TRAPPING (1 << 18) /* switching from STOPPED to TRACED */
+#define GROUP_STOP_DEQUEUED (1 << 19) /* stop signal dequeued */
+
+extern void task_clear_group_stop_pending(struct task_struct *task);
+
#ifdef CONFIG_PREEMPT_RCU
#define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 29a68ac..a822300 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -125,13 +125,13 @@
#define _sig_and(x,y) ((x) & (y))
_SIG_SET_BINOP(sigandsets, _sig_and)
-#define _sig_nand(x,y) ((x) & ~(y))
-_SIG_SET_BINOP(signandsets, _sig_nand)
+#define _sig_andn(x,y) ((x) & ~(y))
+_SIG_SET_BINOP(sigandnsets, _sig_andn)
#undef _SIG_SET_BINOP
#undef _sig_or
#undef _sig_and
-#undef _sig_nand
+#undef _sig_andn
#define _SIG_SET_OP(name, op) \
static inline void name(sigset_t *set) \
@@ -236,6 +236,9 @@
return sig <= _NSIG ? 1 : 0;
}
+struct timespec;
+struct pt_regs;
+
extern int next_signal(struct sigpending *pending, sigset_t *mask);
extern int do_send_sig_info(int sig, struct siginfo *info,
struct task_struct *p, bool group);
@@ -244,10 +247,12 @@
extern long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig,
siginfo_t *info);
extern long do_sigpending(void __user *, unsigned long);
+extern int do_sigtimedwait(const sigset_t *, siginfo_t *,
+ const struct timespec *);
extern int sigprocmask(int, sigset_t *, sigset_t *);
+extern void set_current_blocked(const sigset_t *);
extern int show_unhandled_signals;
-struct pt_regs;
extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, struct pt_regs *regs, void *cookie);
extern void exit_signals(struct task_struct *tsk);
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index ebcfa4e..e95f523 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -469,33 +469,6 @@
}
/**
- * tracehook_notify_jctl - report about job control stop/continue
- * @notify: zero, %CLD_STOPPED or %CLD_CONTINUED
- * @why: %CLD_STOPPED or %CLD_CONTINUED
- *
- * This is called when we might call do_notify_parent_cldstop().
- *
- * @notify is zero if we would not ordinarily send a %SIGCHLD,
- * or is the %CLD_STOPPED or %CLD_CONTINUED .si_code for %SIGCHLD.
- *
- * @why is %CLD_STOPPED when about to stop for job control;
- * we are already in %TASK_STOPPED state, about to call schedule().
- * It might also be that we have just exited (check %PF_EXITING),
- * but need to report that a group-wide stop is complete.
- *
- * @why is %CLD_CONTINUED when waking up after job control stop and
- * ready to make a delayed @notify report.
- *
- * Return the %CLD_* value for %SIGCHLD, or zero to generate no signal.
- *
- * Called with the siglock held.
- */
-static inline int tracehook_notify_jctl(int notify, int why)
-{
- return notify ?: (current->ptrace & PT_PTRACED) ? why : 0;
-}
-
-/**
* tracehook_finish_jctl - report about return from job control stop
*
* This is called by do_signal_stop() after wakeup.
diff --git a/kernel/compat.c b/kernel/compat.c
index 38b1d2c..9214dcd 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -890,10 +890,9 @@
{
compat_sigset_t s32;
sigset_t s;
- int sig;
struct timespec t;
siginfo_t info;
- long ret, timeout = 0;
+ long ret;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
@@ -901,51 +900,19 @@
if (copy_from_user(&s32, uthese, sizeof(compat_sigset_t)))
return -EFAULT;
sigset_from_compat(&s, &s32);
- sigdelsetmask(&s,sigmask(SIGKILL)|sigmask(SIGSTOP));
- signotset(&s);
if (uts) {
- if (get_compat_timespec (&t, uts))
+ if (get_compat_timespec(&t, uts))
return -EFAULT;
- if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0
- || t.tv_sec < 0)
- return -EINVAL;
}
- spin_lock_irq(¤t->sighand->siglock);
- sig = dequeue_signal(current, &s, &info);
- if (!sig) {
- timeout = MAX_SCHEDULE_TIMEOUT;
- if (uts)
- timeout = timespec_to_jiffies(&t)
- +(t.tv_sec || t.tv_nsec);
- if (timeout) {
- current->real_blocked = current->blocked;
- sigandsets(¤t->blocked, ¤t->blocked, &s);
+ ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
-
- timeout = schedule_timeout_interruptible(timeout);
-
- spin_lock_irq(¤t->sighand->siglock);
- sig = dequeue_signal(current, &s, &info);
- current->blocked = current->real_blocked;
- siginitset(¤t->real_blocked, 0);
- recalc_sigpending();
- }
+ if (ret > 0 && uinfo) {
+ if (copy_siginfo_to_user32(uinfo, &info))
+ ret = -EFAULT;
}
- spin_unlock_irq(¤t->sighand->siglock);
- if (sig) {
- ret = sig;
- if (uinfo) {
- if (copy_siginfo_to_user32(uinfo, &info))
- ret = -EFAULT;
- }
- }else {
- ret = timeout?-EINTR:-EAGAIN;
- }
return ret;
}
diff --git a/kernel/exit.c b/kernel/exit.c
index 8dd8741..20a4064 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1377,11 +1377,23 @@
return NULL;
}
-/*
- * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
- * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
- * the lock and this task is uninteresting. If we return nonzero, we have
- * released the lock and the system call should return.
+/**
+ * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
+ * @wo: wait options
+ * @ptrace: is the wait for ptrace
+ * @p: task to wait for
+ *
+ * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
+ *
+ * CONTEXT:
+ * read_lock(&tasklist_lock), which is released if return value is
+ * non-zero. Also, grabs and releases @p->sighand->siglock.
+ *
+ * RETURNS:
+ * 0 if wait condition didn't exist and search for other wait conditions
+ * should continue. Non-zero return, -errno on failure and @p's pid on
+ * success, implies that tasklist_lock is released and wait condition
+ * search should terminate.
*/
static int wait_task_stopped(struct wait_opts *wo,
int ptrace, struct task_struct *p)
@@ -1397,6 +1409,9 @@
if (!ptrace && !(wo->wo_flags & WUNTRACED))
return 0;
+ if (!task_stopped_code(p, ptrace))
+ return 0;
+
exit_code = 0;
spin_lock_irq(&p->sighand->siglock);
@@ -1538,33 +1553,84 @@
return 0;
}
- if (likely(!ptrace) && unlikely(task_ptrace(p))) {
- /*
- * This child is hidden by ptrace.
- * We aren't allowed to see it now, but eventually we will.
- */
- wo->notask_error = 0;
- return 0;
- }
-
+ /* dead body doesn't have much to contribute */
if (p->exit_state == EXIT_DEAD)
return 0;
- /*
- * We don't reap group leaders with subthreads.
- */
- if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p))
- return wait_task_zombie(wo, p);
+ /* slay zombie? */
+ if (p->exit_state == EXIT_ZOMBIE) {
+ /*
+ * A zombie ptracee is only visible to its ptracer.
+ * Notification and reaping will be cascaded to the real
+ * parent when the ptracer detaches.
+ */
+ if (likely(!ptrace) && unlikely(task_ptrace(p))) {
+ /* it will become visible, clear notask_error */
+ wo->notask_error = 0;
+ return 0;
+ }
+
+ /* we don't reap group leaders with subthreads */
+ if (!delay_group_leader(p))
+ return wait_task_zombie(wo, p);
+
+ /*
+ * Allow access to stopped/continued state via zombie by
+ * falling through. Clearing of notask_error is complex.
+ *
+ * When !@ptrace:
+ *
+ * If WEXITED is set, notask_error should naturally be
+ * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
+ * so, if there are live subthreads, there are events to
+ * wait for. If all subthreads are dead, it's still safe
+ * to clear - this function will be called again in finite
+ * amount time once all the subthreads are released and
+ * will then return without clearing.
+ *
+ * When @ptrace:
+ *
+ * Stopped state is per-task and thus can't change once the
+ * target task dies. Only continued and exited can happen.
+ * Clear notask_error if WCONTINUED | WEXITED.
+ */
+ if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
+ wo->notask_error = 0;
+ } else {
+ /*
+ * If @p is ptraced by a task in its real parent's group,
+ * hide group stop/continued state when looking at @p as
+ * the real parent; otherwise, a single stop can be
+ * reported twice as group and ptrace stops.
+ *
+ * If a ptracer wants to distinguish the two events for its
+ * own children, it should create a separate process which
+ * takes the role of real parent.
+ */
+ if (likely(!ptrace) && task_ptrace(p) &&
+ same_thread_group(p->parent, p->real_parent))
+ return 0;
+
+ /*
+ * @p is alive and it's gonna stop, continue or exit, so
+ * there always is something to wait for.
+ */
+ wo->notask_error = 0;
+ }
/*
- * It's stopped or running now, so it might
- * later continue, exit, or stop again.
+ * Wait for stopped. Depending on @ptrace, different stopped state
+ * is used and the two don't interact with each other.
*/
- wo->notask_error = 0;
+ ret = wait_task_stopped(wo, ptrace, p);
+ if (ret)
+ return ret;
- if (task_stopped_code(p, ptrace))
- return wait_task_stopped(wo, ptrace, p);
-
+ /*
+ * Wait for continued. There's only one continued state and the
+ * ptracer can consume it which can confuse the real parent. Don't
+ * use WCONTINUED from ptracer. You don't need or want it.
+ */
return wait_task_continued(wo, p);
}
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index dc7ab65..7a81fc0 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -38,35 +38,33 @@
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)
{
@@ -76,8 +74,27 @@
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);
}
/*
@@ -96,16 +113,14 @@
*/
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);
@@ -169,6 +184,7 @@
static int ptrace_attach(struct task_struct *task)
{
+ bool wait_trap = false;
int retval;
audit_ptrace(task);
@@ -208,12 +224,42 @@
__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;
}
@@ -316,8 +362,6 @@
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);
diff --git a/kernel/signal.c b/kernel/signal.c
index 7165af5..ad5e818 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -124,7 +124,7 @@
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);
@@ -223,6 +223,83 @@
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_key(&task->parent->signal->wait_chldexit,
+ TASK_UNINTERRUPTIBLE, 1, task);
+ }
+}
+
+/**
+ * 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
@@ -527,7 +604,7 @@
* 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) {
/*
@@ -592,7 +669,7 @@
if (sigisemptyset(&m))
return 0;
- signandsets(&s->signal, &s->signal, mask);
+ sigandnsets(&s->signal, &s->signal, mask);
list_for_each_entry_safe(q, n, &s->list, list) {
if (sigismember(mask, q->info.si_signo)) {
list_del_init(&q->list);
@@ -727,34 +804,14 @@
} 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);
/*
@@ -780,13 +837,6 @@
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;
}
}
@@ -875,6 +925,7 @@
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);
@@ -1109,6 +1160,7 @@
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 */
@@ -1536,16 +1588,30 @@
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;
}
@@ -1621,6 +1687,15 @@
}
/*
+ * 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.
*
* This should be the path for all ptrace stops.
@@ -1631,10 +1706,12 @@
* 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
@@ -1655,21 +1732,49 @@
}
/*
- * 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.
@@ -1684,7 +1789,16 @@
/*
* 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;
@@ -1728,7 +1842,7 @@
/* 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);
}
@@ -1741,66 +1855,115 @@
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;
}
+
+ /*
+ * 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;
+ }
+
+ /* PTRACE_ATTACH might have raced with task killing, clear trapping */
+ task_clear_group_stop_trapping(current);
+
spin_unlock_irq(¤t->sighand->siglock);
- if (notify) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, notify);
- read_unlock(&tasklist_lock);
- }
-
- /* Now we don't run again until woken by SIGCONT or SIGKILL */
- do {
- schedule();
- } while (try_to_freeze());
-
tracehook_finish_jctl();
- current->exit_code = 0;
return 1;
}
@@ -1814,7 +1977,7 @@
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;
@@ -1869,18 +2032,36 @@
* 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;
}
@@ -1897,8 +2078,8 @@
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,
@@ -2017,10 +2198,42 @@
return signr;
}
+/*
+ * It could be that complete_signal() picked us to notify about the
+ * group-wide signal. Other threads should be notified now to take
+ * the shared signals in @which since we will not.
+ */
+static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
+{
+ sigset_t retarget;
+ struct task_struct *t;
+
+ sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
+ if (sigisemptyset(&retarget))
+ return;
+
+ t = tsk;
+ while_each_thread(tsk, t) {
+ if (t->flags & PF_EXITING)
+ continue;
+
+ if (!has_pending_signals(&retarget, &t->blocked))
+ continue;
+ /* Remove the signals this thread can handle. */
+ sigandsets(&retarget, &retarget, &t->blocked);
+
+ if (!signal_pending(t))
+ signal_wake_up(t, 0);
+
+ if (sigisemptyset(&retarget))
+ break;
+ }
+}
+
void exit_signals(struct task_struct *tsk)
{
int group_stop = 0;
- struct task_struct *t;
+ sigset_t unblocked;
if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
tsk->flags |= PF_EXITING;
@@ -2036,26 +2249,23 @@
if (!signal_pending(tsk))
goto out;
- /*
- * 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.
- */
- for (t = tsk; (t = next_thread(t)) != tsk; )
- if (!signal_pending(t) && !(t->flags & PF_EXITING))
- recalc_sigpending_and_wake(t);
+ unblocked = tsk->blocked;
+ signotset(&unblocked);
+ retarget_shared_pending(tsk, &unblocked);
- 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);
}
}
@@ -2089,11 +2299,33 @@
return -EINTR;
}
-/*
- * We don't need to get the kernel lock - this is all local to this
- * particular thread.. (and that's good, because this is _heavily_
- * used by various programs)
+static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
+{
+ if (signal_pending(tsk) && !thread_group_empty(tsk)) {
+ sigset_t newblocked;
+ /* A set of now blocked but previously unblocked signals. */
+ sigandnsets(&newblocked, newset, ¤t->blocked);
+ retarget_shared_pending(tsk, &newblocked);
+ }
+ tsk->blocked = *newset;
+ recalc_sigpending();
+}
+
+/**
+ * set_current_blocked - change current->blocked mask
+ * @newset: new mask
+ *
+ * It is wrong to change ->blocked directly, this helper should be used
+ * to ensure the process can't miss a shared signal we are going to block.
*/
+void set_current_blocked(const sigset_t *newset)
+{
+ struct task_struct *tsk = current;
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ __set_task_blocked(tsk, newset);
+ spin_unlock_irq(&tsk->sighand->siglock);
+}
/*
* This is also useful for kernel threads that want to temporarily
@@ -2105,30 +2337,29 @@
*/
int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
{
- int error;
+ struct task_struct *tsk = current;
+ sigset_t newset;
- spin_lock_irq(¤t->sighand->siglock);
+ /* Lockless, only current can change ->blocked, never from irq */
if (oldset)
- *oldset = current->blocked;
+ *oldset = tsk->blocked;
- error = 0;
switch (how) {
case SIG_BLOCK:
- sigorsets(¤t->blocked, ¤t->blocked, set);
+ sigorsets(&newset, &tsk->blocked, set);
break;
case SIG_UNBLOCK:
- signandsets(¤t->blocked, ¤t->blocked, set);
+ sigandnsets(&newset, &tsk->blocked, set);
break;
case SIG_SETMASK:
- current->blocked = *set;
+ newset = *set;
break;
default:
- error = -EINVAL;
+ return -EINVAL;
}
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
- return error;
+ set_current_blocked(&newset);
+ return 0;
}
/**
@@ -2138,40 +2369,34 @@
* @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,
+SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
sigset_t __user *, oset, size_t, sigsetsize)
{
- int error = -EINVAL;
sigset_t old_set, new_set;
+ int error;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
- goto out;
+ return -EINVAL;
- if (set) {
- error = -EFAULT;
- if (copy_from_user(&new_set, set, sizeof(*set)))
- goto out;
+ old_set = current->blocked;
+
+ if (nset) {
+ if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
+ return -EFAULT;
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
- error = sigprocmask(how, &new_set, &old_set);
+ error = sigprocmask(how, &new_set, NULL);
if (error)
- goto out;
- if (oset)
- goto set_old;
- } else if (oset) {
- spin_lock_irq(¤t->sighand->siglock);
- old_set = current->blocked;
- spin_unlock_irq(¤t->sighand->siglock);
-
- set_old:
- error = -EFAULT;
- if (copy_to_user(oset, &old_set, sizeof(*oset)))
- goto out;
+ return error;
}
- error = 0;
-out:
- return error;
+
+ if (oset) {
+ if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
+ return -EFAULT;
+ }
+
+ return 0;
}
long do_sigpending(void __user *set, unsigned long sigsetsize)
@@ -2284,6 +2509,66 @@
#endif
/**
+ * do_sigtimedwait - wait for queued signals specified in @which
+ * @which: queued signals to wait for
+ * @info: if non-null, the signal's siginfo is returned here
+ * @ts: upper bound on process time suspension
+ */
+int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
+ const struct timespec *ts)
+{
+ struct task_struct *tsk = current;
+ long timeout = MAX_SCHEDULE_TIMEOUT;
+ sigset_t mask = *which;
+ int sig;
+
+ if (ts) {
+ if (!timespec_valid(ts))
+ return -EINVAL;
+ timeout = timespec_to_jiffies(ts);
+ /*
+ * We can be close to the next tick, add another one
+ * to ensure we will wait at least the time asked for.
+ */
+ if (ts->tv_sec || ts->tv_nsec)
+ timeout++;
+ }
+
+ /*
+ * Invert the set of allowed signals to get those we want to block.
+ */
+ sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+ signotset(&mask);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ sig = dequeue_signal(tsk, &mask, info);
+ if (!sig && timeout) {
+ /*
+ * None ready, temporarily unblock those we're interested
+ * while we are sleeping in so that we'll be awakened when
+ * they arrive. Unblocking is always fine, we can avoid
+ * set_current_blocked().
+ */
+ tsk->real_blocked = tsk->blocked;
+ sigandsets(&tsk->blocked, &tsk->blocked, &mask);
+ recalc_sigpending();
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ timeout = schedule_timeout_interruptible(timeout);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ __set_task_blocked(tsk, &tsk->real_blocked);
+ siginitset(&tsk->real_blocked, 0);
+ sig = dequeue_signal(tsk, &mask, info);
+ }
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ if (sig)
+ return sig;
+ return timeout ? -EINTR : -EAGAIN;
+}
+
+/**
* sys_rt_sigtimedwait - synchronously wait for queued signals specified
* in @uthese
* @uthese: queued signals to wait for
@@ -2295,11 +2580,10 @@
siginfo_t __user *, uinfo, const struct timespec __user *, uts,
size_t, sigsetsize)
{
- int ret, sig;
sigset_t these;
struct timespec ts;
siginfo_t info;
- long timeout = 0;
+ int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
@@ -2308,61 +2592,16 @@
if (copy_from_user(&these, uthese, sizeof(these)))
return -EFAULT;
- /*
- * Invert the set of allowed signals to get those we
- * want to block.
- */
- sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));
- signotset(&these);
-
if (uts) {
if (copy_from_user(&ts, uts, sizeof(ts)))
return -EFAULT;
- if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0
- || ts.tv_sec < 0)
- return -EINVAL;
}
- spin_lock_irq(¤t->sighand->siglock);
- sig = dequeue_signal(current, &these, &info);
- if (!sig) {
- timeout = MAX_SCHEDULE_TIMEOUT;
- if (uts)
- timeout = (timespec_to_jiffies(&ts)
- + (ts.tv_sec || ts.tv_nsec));
+ ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
- if (timeout) {
- /*
- * None ready -- temporarily unblock those we're
- * interested while we are sleeping in so that we'll
- * be awakened when they arrive.
- */
- current->real_blocked = current->blocked;
- sigandsets(¤t->blocked, ¤t->blocked, &these);
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
-
- timeout = schedule_timeout_interruptible(timeout);
-
- spin_lock_irq(¤t->sighand->siglock);
- sig = dequeue_signal(current, &these, &info);
- current->blocked = current->real_blocked;
- siginitset(¤t->real_blocked, 0);
- recalc_sigpending();
- }
- }
- spin_unlock_irq(¤t->sighand->siglock);
-
- if (sig) {
- ret = sig;
- if (uinfo) {
- if (copy_siginfo_to_user(uinfo, &info))
- ret = -EFAULT;
- }
- } else {
- ret = -EAGAIN;
- if (timeout)
- ret = -EINTR;
+ if (ret > 0 && uinfo) {
+ if (copy_siginfo_to_user(uinfo, &info))
+ ret = -EFAULT;
}
return ret;
@@ -2650,60 +2889,51 @@
/**
* sys_sigprocmask - examine and change blocked signals
* @how: whether to add, remove, or set signals
- * @set: signals to add or remove (if non-null)
+ * @nset: 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,
+SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
old_sigset_t __user *, oset)
{
- int error;
old_sigset_t old_set, new_set;
+ sigset_t new_blocked;
- if (set) {
- error = -EFAULT;
- if (copy_from_user(&new_set, set, sizeof(*set)))
- goto out;
+ old_set = current->blocked.sig[0];
+
+ if (nset) {
+ if (copy_from_user(&new_set, nset, sizeof(*nset)))
+ return -EFAULT;
new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
- spin_lock_irq(¤t->sighand->siglock);
- old_set = current->blocked.sig[0];
+ new_blocked = current->blocked;
- error = 0;
switch (how) {
- default:
- error = -EINVAL;
- break;
case SIG_BLOCK:
- sigaddsetmask(¤t->blocked, new_set);
+ sigaddsetmask(&new_blocked, new_set);
break;
case SIG_UNBLOCK:
- sigdelsetmask(¤t->blocked, new_set);
+ sigdelsetmask(&new_blocked, new_set);
break;
case SIG_SETMASK:
- current->blocked.sig[0] = new_set;
+ new_blocked.sig[0] = new_set;
break;
+ default:
+ return -EINVAL;
}
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
- if (error)
- goto out;
- if (oset)
- goto set_old;
- } else if (oset) {
- old_set = current->blocked.sig[0];
- set_old:
- error = -EFAULT;
- if (copy_to_user(oset, &old_set, sizeof(*oset)))
- goto out;
+ set_current_blocked(&new_blocked);
}
- error = 0;
-out:
- return error;
+
+ if (oset) {
+ if (copy_to_user(oset, &old_set, sizeof(*oset)))
+ return -EFAULT;
+ }
+
+ return 0;
}
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */