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authorBen Collins <bcollins@debian.org>2005-11-28 13:43:56 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-28 14:42:23 -0800
commitbce61dd49d6ba7799be2de17c772e4c701558f14 (patch)
treea8fd75afc85ffef3c9af0bafa1989d7a14e1a187 /kernel
parentee500f274914653a7d3dfca7d0140a3d21658e32 (diff)
downloadlinux-bce61dd49d6ba7799be2de17c772e4c701558f14.tar.gz
[PATCH] Fix hardcoded cpu=0 in workqueue for per_cpu_ptr() calls
Tracked this down on an Ultra Enterprise 3000.  It's a 6-way machine.  Odd
thing about this machine (and it's good for finding bugs like this) is that
the CPU id's are not 0 based.  For instance, on my machine the CPU's are
6/7/10/11/14/15.

This caused some NULL pointer dereference in kernel/workqueue.c because for
single_threaded workqueue's, it hardcoded the cpu to 0.

I changed the 0's to any_online_cpu(cpu_online_mask), which cpumask.h
claims is "First cpu in mask".  So this fits the same usage.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/workqueue.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 42df83d7fad2..2bd5aee1c736 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -102,7 +102,7 @@ int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work)
 
 	if (!test_and_set_bit(0, &work->pending)) {
 		if (unlikely(is_single_threaded(wq)))
-			cpu = 0;
+			cpu = any_online_cpu(cpu_online_map);
 		BUG_ON(!list_empty(&work->entry));
 		__queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
 		ret = 1;
@@ -118,7 +118,7 @@ static void delayed_work_timer_fn(unsigned long __data)
 	int cpu = smp_processor_id();
 
 	if (unlikely(is_single_threaded(wq)))
-		cpu = 0;
+		cpu = any_online_cpu(cpu_online_map);
 
 	__queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
 }
@@ -266,8 +266,8 @@ void fastcall flush_workqueue(struct workqueue_struct *wq)
 	might_sleep();
 
 	if (is_single_threaded(wq)) {
-		/* Always use cpu 0's area. */
-		flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, 0));
+		/* Always use first cpu's area. */
+		flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, any_online_cpu(cpu_online_map)));
 	} else {
 		int cpu;
 
@@ -320,7 +320,7 @@ struct workqueue_struct *__create_workqueue(const char *name,
 	lock_cpu_hotplug();
 	if (singlethread) {
 		INIT_LIST_HEAD(&wq->list);
-		p = create_workqueue_thread(wq, 0);
+		p = create_workqueue_thread(wq, any_online_cpu(cpu_online_map));
 		if (!p)
 			destroy = 1;
 		else
@@ -374,7 +374,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
 	/* We don't need the distraction of CPUs appearing and vanishing. */
 	lock_cpu_hotplug();
 	if (is_single_threaded(wq))
-		cleanup_workqueue_thread(wq, 0);
+		cleanup_workqueue_thread(wq, any_online_cpu(cpu_online_map));
 	else {
 		for_each_online_cpu(cpu)
 			cleanup_workqueue_thread(wq, cpu);