[patch 205/262] stacktrace: move filter_irq_stacks() to kernel/stacktrace.c

Andrew Morton
2021-11-05T20:45:28Z

From: Marco Elver <elver@google.com>
Subject: stacktrace: move filter_irq_stacks() to kernel/stacktrace.c

filter_irq_stacks() has little to do with the stackdepot implementation,
except that it is usually used by users (such as KASAN) of stackdepot to
reduce the stack trace.

However, filter_irq_stacks() itself is not useful without a stack trace as
obtained by stack_trace_save() and friends.

Therefore, move filter_irq_stacks() to kernel/stacktrace.c, so that new
users of filter_irq_stacks() do not have to start depending on STACKDEPOT
only for filter_irq_stacks().

Link: https://lkml.kernel.org/r/20210923104803.2620285-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Taras Madan <tarasmadan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/stackdepot.h | 2 --
include/linux/stacktrace.h | 1 +
kernel/stacktrace.c | 30 ++++++++++++++++++++++++++++++
lib/stackdepot.c | 24 ------------------------
4 files changed, 31 insertions(+), 26 deletions(-)

--- a/include/linux/stackdepot.h~stacktrace-move-filter_irq_stacks-to-kernel-stacktracec
+++ a/include/linux/stackdepot.h
@@ -25,8 +25,6 @@ depot_stack_handle_t stack_depot_save(un
unsigned int stack_depot_fetch(depot_stack_handle_t handle,
unsigned long **entries);

-unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries);
-
#ifdef CONFIG_STACKDEPOT
int stack_depot_init(void);
#else
--- a/include/linux/stacktrace.h~stacktrace-move-filter_irq_stacks-to-kernel-stacktracec
+++ a/include/linux/stacktrace.h
@@ -21,6 +21,7 @@ unsigned int stack_trace_save_tsk(struct
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
unsigned int size, unsigned int skipnr);
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size);
+unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries);

/* Internal interfaces. Do not use in generic code */
#ifdef CONFIG_ARCH_STACKWALK
--- a/kernel/stacktrace.c~stacktrace-move-filter_irq_stacks-to-kernel-stacktracec
+++ a/kernel/stacktrace.c
@@ -13,6 +13,7 @@
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
+#include <linux/interrupt.h>

/**
* stack_trace_print - Print the entries in the stack trace
@@ -373,3 +374,32 @@ unsigned int stack_trace_save_user(unsig
#endif /* CONFIG_USER_STACKTRACE_SUPPORT */

#endif /* !CONFIG_ARCH_STACKWALK */
+
+static inline bool 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);
+}
+
+/**
+ * filter_irq_stacks - Find first IRQ stack entry in trace
+ * @entries: Pointer to stack trace array
+ * @nr_entries: Number of entries in the storage array
+ *
+ * Return: Number of trace entries until IRQ stack starts.
+ */
+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);
--- a/lib/stackdepot.c~stacktrace-move-filter_irq_stacks-to-kernel-stacktracec
+++ a/lib/stackdepot.c
@@ -20,7 +20,6 @@
*/

#include <linux/gfp.h>
-#include <linux/interrupt.h>
#include <linux/jhash.h>
#include <linux/kernel.h>
#include <linux/mm.h>
@@ -371,26 +370,3 @@ depot_stack_handle_t stack_depot_save(un
return __stack_depot_save(entries, nr_entries, alloc_flags, true);
}
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);
_