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authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-21 23:47:29 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-21 23:47:29 +0300
commit0214f46b3a0383d6e33c297e7706216b6a550e4b (patch)
tree98f94fa818963d4c2b5ad2a16cd97ec19d036dce /kernel/time
parent40fafdcbcd7a74e80ab0229b35bf6e497831e28f (diff)
parent84fe4cc09abc1a5ef3a282db3ed10f4d3f1e6a0b (diff)
downloadlinux-0214f46b3a0383d6e33c297e7706216b6a550e4b.tar.xz
Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull core signal handling updates from Eric Biederman: "It was observed that a periodic timer in combination with a sufficiently expensive fork could prevent fork from every completing. This contains the changes to remove the need for that restart. This set of changes is split into several parts: - The first part makes PIDTYPE_TGID a proper pid type instead something only for very special cases. The part starts using PIDTYPE_TGID enough so that in __send_signal where signals are actually delivered we know if the signal is being sent to a a group of processes or just a single process. - With that prep work out of the way the logic in fork is modified so that fork logically makes signals received while it is running appear to be received after the fork completes" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits) signal: Don't send signals to tasks that don't exist signal: Don't restart fork when signals come in. fork: Have new threads join on-going signal group stops fork: Skip setting TIF_SIGPENDING in ptrace_init_task signal: Add calculate_sigpending() fork: Unconditionally exit if a fatal signal is pending fork: Move and describe why the code examines PIDNS_ADDING signal: Push pid type down into complete_signal. signal: Push pid type down into __send_signal signal: Push pid type down into send_signal signal: Pass pid type into do_send_sig_info signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task signal: Pass pid type into group_send_sig_info signal: Pass pid and pid type into send_sigqueue posix-timers: Noralize good_sigevent signal: Use PIDTYPE_TGID to clearly store where file signals will be sent pid: Implement PIDTYPE_TGID pids: Move the pgrp and session pid pointers from task_struct to signal_struct kvm: Don't open code task_pid in kvm_vcpu_ioctl pids: Compute task_tgid using signal->leader_pid ...
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/itimer.c5
-rw-r--r--kernel/time/posix-cpu-timers.c2
-rw-r--r--kernel/time/posix-timers.c21
3 files changed, 13 insertions, 15 deletions
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index f26acef5d7b4..9a65713c8309 100644
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -139,9 +139,10 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer)
{
struct signal_struct *sig =
container_of(timer, struct signal_struct, real_timer);
+ struct pid *leader_pid = sig->pids[PIDTYPE_TGID];
- trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
- kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
+ trace_itimer_expire(ITIMER_REAL, leader_pid, 0);
+ kill_pid_info(SIGALRM, SEND_SIG_PRIV, leader_pid);
return HRTIMER_NORESTART;
}
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 294d7b65af33..ce32cf741b25 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -894,7 +894,7 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
trace_itimer_expire(signo == SIGPROF ?
ITIMER_PROF : ITIMER_VIRTUAL,
- tsk->signal->leader_pid, cur_time);
+ task_tgid(tsk), cur_time);
__group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
}
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index f23cc46ecf3e..4b9127e95430 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -333,8 +333,8 @@ void posixtimer_rearm(struct siginfo *info)
int posix_timer_event(struct k_itimer *timr, int si_private)
{
- struct task_struct *task;
- int shared, ret = -1;
+ enum pid_type type;
+ int ret = -1;
/*
* FIXME: if ->sigq is queued we can race with
* dequeue_signal()->posixtimer_rearm().
@@ -348,13 +348,8 @@ int posix_timer_event(struct k_itimer *timr, int si_private)
*/
timr->sigq->info.si_sys_private = si_private;
- rcu_read_lock();
- task = pid_task(timr->it_pid, PIDTYPE_PID);
- if (task) {
- shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
- ret = send_sigqueue(timr->sigq, task, shared);
- }
- rcu_read_unlock();
+ type = !(timr->it_sigev_notify & SIGEV_THREAD_ID) ? PIDTYPE_TGID : PIDTYPE_PID;
+ ret = send_sigqueue(timr->sigq, timr->it_pid, type);
/* If we failed to send the signal the timer stops. */
return ret > 0;
}
@@ -433,11 +428,13 @@ static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
static struct pid *good_sigevent(sigevent_t * event)
{
- struct task_struct *rtn = current->group_leader;
+ struct pid *pid = task_tgid(current);
+ struct task_struct *rtn;
switch (event->sigev_notify) {
case SIGEV_SIGNAL | SIGEV_THREAD_ID:
- rtn = find_task_by_vpid(event->sigev_notify_thread_id);
+ pid = find_vpid(event->sigev_notify_thread_id);
+ rtn = pid_task(pid, PIDTYPE_PID);
if (!rtn || !same_thread_group(rtn, current))
return NULL;
/* FALLTHRU */
@@ -447,7 +444,7 @@ static struct pid *good_sigevent(sigevent_t * event)
return NULL;
/* FALLTHRU */
case SIGEV_NONE:
- return task_pid(rtn);
+ return pid;
default:
return NULL;
}