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authorOleg Nesterov <oleg@redhat.com>2015-11-06 16:32:19 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-06 17:50:42 -0800
commit2e01fabe67ccaff1d59bda01e60a61f5fb0aa7b6 (patch)
tree4db02540f4e0f4f3981965b86ee43cbd88ae517e /kernel
parent4f05028f8d1af782cfd03d09e0a052e9745dc5ad (diff)
signals: kill block_all_signals() and unblock_all_signals()
It is hardly possible to enumerate all problems with block_all_signals() and unblock_all_signals(). Just for example, 1. block_all_signals(SIGSTOP/etc) simply can't help if the caller is multithreaded. Another thread can dequeue the signal and force the group stop. 2. Even is the caller is single-threaded, it will "stop" anyway. It will not sleep, but it will spin in kernel space until SIGCONT or SIGKILL. And a lot more. In short, this interface doesn't work at all, at least the last 10+ years. Daniel said: Yeah the only times I played around with the DRM_LOCK stuff was when old drivers accidentally deadlocked - my impression is that the entire DRM_LOCK thing was never really tested properly ;-) Hence I'm all for purging where this leaks out of the drm subsystem. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Dave Airlie <airlied@redhat.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/signal.c51
1 files changed, 1 insertions, 50 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 0f6bbbe77b46..f2cbd4ed5cd4 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -503,41 +503,6 @@ int unhandled_signal(struct task_struct *tsk, int sig)
return !tsk->ptrace;
}
-/*
- * 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.
- */
-void
-block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&current->sighand->siglock, flags);
- current->notifier_mask = mask;
- current->notifier_data = priv;
- current->notifier = notifier;
- spin_unlock_irqrestore(&current->sighand->siglock, flags);
-}
-
-/* Notify the system that blocking has ended. */
-
-void
-unblock_all_signals(void)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&current->sighand->siglock, flags);
- current->notifier = NULL;
- current->notifier_data = NULL;
- recalc_sigpending();
- spin_unlock_irqrestore(&current->sighand->siglock, flags);
-}
-
static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
{
struct sigqueue *q, *first = NULL;
@@ -580,19 +545,8 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
{
int sig = next_signal(pending, mask);
- if (sig) {
- if (current->notifier) {
- if (sigismember(current->notifier_mask, sig)) {
- if (!(current->notifier)(current->notifier_data)) {
- clear_thread_flag(TIF_SIGPENDING);
- return 0;
- }
- }
- }
-
+ if (sig)
collect_signal(sig, pending, info);
- }
-
return sig;
}
@@ -2483,9 +2437,6 @@ EXPORT_SYMBOL(force_sig);
EXPORT_SYMBOL(send_sig);
EXPORT_SYMBOL(send_sig_info);
EXPORT_SYMBOL(sigprocmask);
-EXPORT_SYMBOL(block_all_signals);
-EXPORT_SYMBOL(unblock_all_signals);
-
/*
* System call entry points.