1 files changed, 43 insertions, 4 deletions

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index ed717dd08ff3..2caffc64e4c8 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -20,6 +20,7 @@
  */
 
 #include <linux/gfp.h>
+#include <linux/interrupt.h>
 #include <linux/jhash.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
@@ -83,15 +84,19 @@ static bool init_stack_slab(void **prealloc)
 		return true;
 	if (stack_slabs[depot_index] == NULL) {
 		stack_slabs[depot_index] = *prealloc;
+		*prealloc = NULL;
 	} else {
-		stack_slabs[depot_index + 1] = *prealloc;
+		/* If this is the last depot slab, do not touch the next one. */
+		if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) {
+			stack_slabs[depot_index + 1] = *prealloc;
+			*prealloc = NULL;
+		}
 		/*
 		 * This smp_store_release pairs with smp_load_acquire() from
 		 * |next_slab_inited| above and in stack_depot_save().
 		 */
 		smp_store_release(&next_slab_inited, 1);
 	}
-	*prealloc = NULL;
 	return true;
 }
 
@@ -198,9 +203,20 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle,
 			       unsigned long **entries)
 {
 	union handle_parts parts = { .handle = handle };
-	void *slab = stack_slabs[parts.slabindex];
+	void *slab;
 	size_t offset = parts.offset << STACK_ALLOC_ALIGN;
-	struct stack_record *stack = slab + offset;
+	struct stack_record *stack;
+
+	*entries = NULL;
+	if (parts.slabindex > depot_index) {
+		WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n",
+			parts.slabindex, depot_index, handle);
+		return 0;
+	}
+	slab = stack_slabs[parts.slabindex];
+	if (!slab)
+		return 0;
+	stack = slab + offset;
 
 	*entries = stack->entries;
 	return stack->size;
@@ -301,3 +317,26 @@ fast_exit:
 	return retval;
 }
 EXPORT_SYMBOL_GPL(stack_depot_save);
+
+static inline int in_irqentry_text(unsigned long ptr)
+{
+	return (ptr >= (unsigned long)&__irqentry_text_start &&
+		ptr < (unsigned long)&__irqentry_text_end) ||
+		(ptr >= (unsigned long)&__softirqentry_text_start &&
+		 ptr < (unsigned long)&__softirqentry_text_end);
+}
+
+unsigned int filter_irq_stacks(unsigned long *entries,
+					     unsigned int nr_entries)
+{
+	unsigned int i;
+
+	for (i = 0; i < nr_entries; i++) {
+		if (in_irqentry_text(entries[i])) {
+			/* Include the irqentry function into the stack. */
+			return i + 1;
+		}
+	}
+	return nr_entries;
+}
+EXPORT_SYMBOL_GPL(filter_irq_stacks);