1 files changed, 36 insertions, 30 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index b0c7aa4..731201b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -997,15 +997,21 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
 			     unsigned nr_pages)
 {
 	struct buffer_page *bpage, *tmp;
-	unsigned long addr;
 	LIST_HEAD(pages);
 	unsigned i;
 
 	WARN_ON(!nr_pages);
 
 	for (i = 0; i < nr_pages; i++) {
+		struct page *page;
+		/*
+		 * __GFP_NORETRY flag makes sure that the allocation fails
+		 * gracefully without invoking oom-killer and the system is
+		 * not destabilized.
+		 */
 		bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
-				    GFP_KERNEL, cpu_to_node(cpu_buffer->cpu));
+				    GFP_KERNEL | __GFP_NORETRY,
+				    cpu_to_node(cpu_buffer->cpu));
 		if (!bpage)
 			goto free_pages;
 
@@ -1013,10 +1019,11 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
 
 		list_add(&bpage->list, &pages);
 
-		addr = __get_free_page(GFP_KERNEL);
-		if (!addr)
+		page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu),
+					GFP_KERNEL | __GFP_NORETRY, 0);
+		if (!page)
 			goto free_pages;
-		bpage->page = (void *)addr;
+		bpage->page = page_address(page);
 		rb_init_page(bpage->page);
 	}
 
@@ -1045,7 +1052,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct buffer_page *bpage;
-	unsigned long addr;
+	struct page *page;
 	int ret;
 
 	cpu_buffer = kzalloc_node(ALIGN(sizeof(*cpu_buffer), cache_line_size()),
@@ -1067,10 +1074,10 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
 	rb_check_bpage(cpu_buffer, bpage);
 
 	cpu_buffer->reader_page = bpage;
-	addr = __get_free_page(GFP_KERNEL);
-	if (!addr)
+	page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, 0);
+	if (!page)
 		goto fail_free_reader;
-	bpage->page = (void *)addr;
+	bpage->page = page_address(page);
 	rb_init_page(bpage->page);
 
 	INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
@@ -1314,7 +1321,6 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
 	unsigned nr_pages, rm_pages, new_pages;
 	struct buffer_page *bpage, *tmp;
 	unsigned long buffer_size;
-	unsigned long addr;
 	LIST_HEAD(pages);
 	int i, cpu;
 
@@ -1375,16 +1381,24 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
 
 	for_each_buffer_cpu(buffer, cpu) {
 		for (i = 0; i < new_pages; i++) {
+			struct page *page;
+			/*
+			 * __GFP_NORETRY flag makes sure that the allocation
+			 * fails gracefully without invoking oom-killer and
+			 * the system is not destabilized.
+			 */
 			bpage = kzalloc_node(ALIGN(sizeof(*bpage),
 						  cache_line_size()),
-					    GFP_KERNEL, cpu_to_node(cpu));
+					    GFP_KERNEL | __GFP_NORETRY,
+					    cpu_to_node(cpu));
 			if (!bpage)
 				goto free_pages;
 			list_add(&bpage->list, &pages);
-			addr = __get_free_page(GFP_KERNEL);
-			if (!addr)
+			page = alloc_pages_node(cpu_to_node(cpu),
+						GFP_KERNEL | __GFP_NORETRY, 0);
+			if (!page)
 				goto free_pages;
-			bpage->page = (void *)addr;
+			bpage->page = page_address(page);
 			rb_init_page(bpage->page);
 		}
 	}
@@ -3730,16 +3744,17 @@ EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
  * Returns:
  *  The page allocated, or NULL on error.
  */
-void *ring_buffer_alloc_read_page(struct ring_buffer *buffer)
+void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu)
 {
 	struct buffer_data_page *bpage;
-	unsigned long addr;
+	struct page *page;
 
-	addr = __get_free_page(GFP_KERNEL);
-	if (!addr)
+	page = alloc_pages_node(cpu_to_node(cpu),
+				GFP_KERNEL | __GFP_NORETRY, 0);
+	if (!page)
 		return NULL;
 
-	bpage = (void *)addr;
+	bpage = page_address(page);
 
 	rb_init_page(bpage);
 
@@ -3978,20 +3993,11 @@ rb_simple_write(struct file *filp, const char __user *ubuf,
 		size_t cnt, loff_t *ppos)
 {
 	unsigned long *p = filp->private_data;
-	char buf[64];
 	unsigned long val;
 	int ret;
 
-	if (cnt >= sizeof(buf))
-		return -EINVAL;
-
-	if (copy_from_user(&buf, ubuf, cnt))
-		return -EFAULT;
-
-	buf[cnt] = 0;
-
-	ret = strict_strtoul(buf, 10, &val);
-	if (ret < 0)
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
 		return ret;
 
 	if (val)