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-rw-r--r--kernel/stacktrace.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index dd55312f3fe9..27bafc1e271e 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -5,6 +5,8 @@
*
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
+#include <linux/sched/task_stack.h>
+#include <linux/sched/debug.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/export.h>
@@ -66,6 +68,175 @@ int stack_trace_snprint(char *buf, size_t size, unsigned long *entries,
}
EXPORT_SYMBOL_GPL(stack_trace_snprint);
+#ifdef CONFIG_ARCH_STACKWALK
+
+struct stacktrace_cookie {
+ unsigned long *store;
+ unsigned int size;
+ unsigned int skip;
+ unsigned int len;
+};
+
+static bool stack_trace_consume_entry(void *cookie, unsigned long addr,
+ bool reliable)
+{
+ struct stacktrace_cookie *c = cookie;
+
+ if (c->len >= c->size)
+ return false;
+
+ if (c->skip > 0) {
+ c->skip--;
+ return true;
+ }
+ c->store[c->len++] = addr;
+ return c->len < c->size;
+}
+
+static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr,
+ bool reliable)
+{
+ if (in_sched_functions(addr))
+ return true;
+ return stack_trace_consume_entry(cookie, addr, reliable);
+}
+
+/**
+ * stack_trace_save - Save a stack trace into a storage array
+ * @store: Pointer to storage array
+ * @size: Size of the storage array
+ * @skipnr: Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save(unsigned long *store, unsigned int size,
+ unsigned int skipnr)
+{
+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+ struct stacktrace_cookie c = {
+ .store = store,
+ .size = size,
+ .skip = skipnr + 1,
+ };
+
+ arch_stack_walk(consume_entry, &c, current, NULL);
+ return c.len;
+}
+EXPORT_SYMBOL_GPL(stack_trace_save);
+
+/**
+ * stack_trace_save_tsk - Save a task stack trace into a storage array
+ * @task: The task to examine
+ * @store: Pointer to storage array
+ * @size: Size of the storage array
+ * @skipnr: Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
+ unsigned int size, unsigned int skipnr)
+{
+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
+ struct stacktrace_cookie c = {
+ .store = store,
+ .size = size,
+ .skip = skipnr + 1,
+ };
+
+ if (!try_get_task_stack(tsk))
+ return 0;
+
+ arch_stack_walk(consume_entry, &c, tsk, NULL);
+ put_task_stack(tsk);
+ return c.len;
+}
+
+/**
+ * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
+ * @regs: Pointer to pt_regs to examine
+ * @store: Pointer to storage array
+ * @size: Size of the storage array
+ * @skipnr: Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
+ unsigned int size, unsigned int skipnr)
+{
+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+ struct stacktrace_cookie c = {
+ .store = store,
+ .size = size,
+ .skip = skipnr,
+ };
+
+ arch_stack_walk(consume_entry, &c, current, regs);
+ return c.len;
+}
+
+#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
+/**
+ * stack_trace_save_tsk_reliable - Save task stack with verification
+ * @tsk: Pointer to the task to examine
+ * @store: Pointer to storage array
+ * @size: Size of the storage array
+ *
+ * Return: An error if it detects any unreliable features of the
+ * stack. Otherwise it guarantees that the stack trace is
+ * reliable and returns the number of entries stored.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
+ unsigned int size)
+{
+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+ struct stacktrace_cookie c = {
+ .store = store,
+ .size = size,
+ };
+ int ret;
+
+ /*
+ * If the task doesn't have a stack (e.g., a zombie), the stack is
+ * "reliably" empty.
+ */
+ if (!try_get_task_stack(tsk))
+ return 0;
+
+ ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
+ put_task_stack(tsk);
+ return ret;
+}
+#endif
+
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
+/**
+ * stack_trace_save_user - Save a user space stack trace into a storage array
+ * @store: Pointer to storage array
+ * @size: Size of the storage array
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
+{
+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+ struct stacktrace_cookie c = {
+ .store = store,
+ .size = size,
+ };
+
+ /* Trace user stack if not a kernel thread */
+ if (!current->mm)
+ return 0;
+
+ arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
+ return c.len;
+}
+#endif
+
+#else /* CONFIG_ARCH_STACKWALK */
+
/*
* Architectures that do not implement save_stack_trace_*()
* get these weak aliases and once-per-bootup warnings
@@ -203,3 +374,5 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
return trace.nr_entries;
}
#endif /* CONFIG_USER_STACKTRACE_SUPPORT */
+
+#endif /* !CONFIG_ARCH_STACKWALK */

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