From 10f02d1c59e55f529140dda3a92f0099d748451c Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@labri.fr>
Date: Sat, 21 May 2005 17:50:15 +0200
Subject: [PATCH] spin_unlock_bh() and preempt_check_resched()
In _spin_unlock_bh(lock):
do { \
_raw_spin_unlock(lock); \
preempt_enable(); \
local_bh_enable(); \
__release(lock); \
} while (0)
there is no reason for using preempt_enable() instead of a simple
preempt_enable_no_resched()
Since we know bottom halves are disabled, preempt_schedule() will always
return at once (preempt_count!=0), and hence preempt_check_resched() is
useless here...
This fixes it by using "preempt_enable_no_resched()" instead of the
"preempt_enable()", and thus avoids the useless preempt_check_resched()
just before re-enabling bottom halves.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
kernel/spinlock.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
(limited to 'kernel')
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index e15ed17863..0c3f9d8bbe 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -294,7 +294,7 @@ EXPORT_SYMBOL(_spin_unlock_irq);
void __lockfunc _spin_unlock_bh(spinlock_t *lock)
{
_raw_spin_unlock(lock);
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_spin_unlock_bh);
@@ -318,7 +318,7 @@ EXPORT_SYMBOL(_read_unlock_irq);
void __lockfunc _read_unlock_bh(rwlock_t *lock)
{
_raw_read_unlock(lock);
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_read_unlock_bh);
@@ -342,7 +342,7 @@ EXPORT_SYMBOL(_write_unlock_irq);
void __lockfunc _write_unlock_bh(rwlock_t *lock)
{
_raw_write_unlock(lock);
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_write_unlock_bh);
@@ -354,7 +354,7 @@ int __lockfunc _spin_trylock_bh(spinlock_t *lock)
if (_raw_spin_trylock(lock))
return 1;
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
return 0;
}
--
cgit v1.2.2
From c33880aaddbbab1ccf36f4457ed1090621f2e39a Mon Sep 17 00:00:00 2001
From: Kirill Korotaev <dev@sw.ru>
Date: Tue, 24 May 2005 19:29:47 -0700
Subject: [PATCH] sigkill priority fix
If SIGKILL does not have priority, we cannot instantly kill task before it
makes some unexpected job. It can be critical, but we were unable to
reproduce this easily until Heiko Carstens <Heiko.Carstens@de.ibm.com>
reported this problem on LKML.
Signed-Off-By: Kirill Korotaev <dev@sw.ru>
Signed-Off-By: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
kernel/signal.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
(limited to 'kernel')
diff --git a/kernel/signal.c b/kernel/signal.c
index 8f3debc77c..b3c24c732c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -522,7 +522,16 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
{
int sig = 0;
- sig = next_signal(pending, mask);
+ /* SIGKILL must have priority, otherwise it is quite easy
+ * to create an unkillable process, sending sig < SIGKILL
+ * to self */
+ if (unlikely(sigismember(&pending->signal, SIGKILL))) {
+ if (!sigismember(mask, SIGKILL))
+ sig = SIGKILL;
+ }
+
+ if (likely(!sig))
+ sig = next_signal(pending, mask);
if (sig) {
if (current->notifier) {
if (sigismember(current->notifier_mask, sig)) {
--
cgit v1.2.2