Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull timer fix from Eric Biederman:
"This fixes an issue of confusing injected signals with the signals
from posix timers that has existed since posix timers have been in the
kernel.
This patch is slightly simpler than my earlier version of this patch
as I discovered in testing that I had misspelled "#ifdef
CONFIG_POSIX_TIMERS". So I deleted that unnecessary test and made
setting of resched_timer uncondtional.
I have tested this and verified that without this patch there is a
nasty hang that is easy to trigger, and with this patch everything
works properly"
Thomas Gleixner dixit:
"It fixes the problem at hand and covers the ptrace case as well, which
I missed.
Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de>"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
signal: Only reschedule timers on signals timers have sent
diff --git a/kernel/signal.c b/kernel/signal.c
index ca92bcf..45b4c1f 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -510,7 +510,8 @@
return !tsk->ptrace;
}
-static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
+static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
+ bool *resched_timer)
{
struct sigqueue *q, *first = NULL;
@@ -532,6 +533,12 @@
still_pending:
list_del_init(&first->list);
copy_siginfo(info, &first->info);
+
+ *resched_timer =
+ (first->flags & SIGQUEUE_PREALLOC) &&
+ (info->si_code == SI_TIMER) &&
+ (info->si_sys_private);
+
__sigqueue_free(first);
} else {
/*
@@ -548,12 +555,12 @@
}
static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
- siginfo_t *info)
+ siginfo_t *info, bool *resched_timer)
{
int sig = next_signal(pending, mask);
if (sig)
- collect_signal(sig, pending, info);
+ collect_signal(sig, pending, info, resched_timer);
return sig;
}
@@ -565,15 +572,16 @@
*/
int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
{
+ bool resched_timer = false;
int signr;
/* We only dequeue private signals from ourselves, we don't let
* signalfd steal them
*/
- signr = __dequeue_signal(&tsk->pending, mask, info);
+ signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
if (!signr) {
signr = __dequeue_signal(&tsk->signal->shared_pending,
- mask, info);
+ mask, info, &resched_timer);
#ifdef CONFIG_POSIX_TIMERS
/*
* itimer signal ?
@@ -621,7 +629,7 @@
current->jobctl |= JOBCTL_STOP_DEQUEUED;
}
#ifdef CONFIG_POSIX_TIMERS
- if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
+ if (resched_timer) {
/*
* Release the siglock to ensure proper locking order
* of timer locks outside of siglocks. Note, we leave
