1 files changed, 38 insertions, 10 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 966128f02121..c9cb9767d49b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -22,6 +22,7 @@
 #include <linux/hash.h>
 #include <linux/list.h>
 #include <linux/cpu.h>
+#include <linux/oom.h>
 
 #include <asm/local.h>
 
@@ -1162,35 +1163,60 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
 static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
 {
 	struct buffer_page *bpage, *tmp;
+	bool user_thread = current->mm != NULL;
+	gfp_t mflags;
 	long i;
 
-	/* Check if the available memory is there first */
+	/*
+	 * Check if the available memory is there first.
+	 * Note, si_mem_available() only gives us a rough estimate of available
+	 * memory. It may not be accurate. But we don't care, we just want
+	 * to prevent doing any allocation when it is obvious that it is
+	 * not going to succeed.
+	 */
 	i = si_mem_available();
 	if (i < nr_pages)
 		return -ENOMEM;
 
+	/*
+	 * __GFP_RETRY_MAYFAIL flag makes sure that the allocation fails
+	 * gracefully without invoking oom-killer and the system is not
+	 * destabilized.
+	 */
+	mflags = GFP_KERNEL | __GFP_RETRY_MAYFAIL;
+
+	/*
+	 * If a user thread allocates too much, and si_mem_available()
+	 * reports there's enough memory, even though there is not.
+	 * Make sure the OOM killer kills this thread. This can happen
+	 * even with RETRY_MAYFAIL because another task may be doing
+	 * an allocation after this task has taken all memory.
+	 * This is the task the OOM killer needs to take out during this
+	 * loop, even if it was triggered by an allocation somewhere else.
+	 */
+	if (user_thread)
+		set_current_oom_origin();
 	for (i = 0; i < nr_pages; i++) {
 		struct page *page;
-		/*
-		 * __GFP_RETRY_MAYFAIL 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 | __GFP_RETRY_MAYFAIL,
-				    cpu_to_node(cpu));
+				    mflags, cpu_to_node(cpu));
 		if (!bpage)
 			goto free_pages;
 
 		list_add(&bpage->list, pages);
 
-		page = alloc_pages_node(cpu_to_node(cpu),
-					GFP_KERNEL | __GFP_RETRY_MAYFAIL, 0);
+		page = alloc_pages_node(cpu_to_node(cpu), mflags, 0);
 		if (!page)
 			goto free_pages;
 		bpage->page = page_address(page);
 		rb_init_page(bpage->page);
+
+		if (user_thread && fatal_signal_pending(current))
+			goto free_pages;
 	}
+	if (user_thread)
+		clear_current_oom_origin();
 
 	return 0;
 
@@ -1199,6 +1225,8 @@ free_pages:
 		list_del_init(&bpage->list);
 		free_buffer_page(bpage);
 	}
+	if (user_thread)
+		clear_current_oom_origin();
 
 	return -ENOMEM;
 }