1 files changed, 41 insertions, 36 deletions

diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index f6a620f854e1..fc5419ac64c8 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -6,57 +6,62 @@
  *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
  */
 
-#include <linux/sched.h>
-#include <linux/sched/debug.h>
 #include <linux/stacktrace.h>
-#include <linux/kallsyms.h>
-#include <linux/export.h>
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
+#include <asm/kprobes.h>
 
-void save_stack_trace(struct stack_trace *trace)
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+		     struct task_struct *task, struct pt_regs *regs)
 {
 	struct unwind_state state;
+	unsigned long addr;
 
-	unwind_for_each_frame(&state, current, NULL, 0) {
-		if (trace->nr_entries >= trace->max_entries)
+	unwind_for_each_frame(&state, task, regs, 0) {
+		addr = unwind_get_return_address(&state);
+		if (!addr || !consume_entry(cookie, addr, false))
 			break;
-		if (trace->skip > 0)
-			trace->skip--;
-		else
-			trace->entries[trace->nr_entries++] = state.ip;
 	}
 }
-EXPORT_SYMBOL_GPL(save_stack_trace);
 
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+/*
+ * This function returns an error if it detects any unreliable features of the
+ * stack.  Otherwise it guarantees that the stack trace is reliable.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+			     void *cookie, struct task_struct *task)
 {
 	struct unwind_state state;
+	unsigned long addr;
 
-	unwind_for_each_frame(&state, tsk, NULL, 0) {
-		if (trace->nr_entries >= trace->max_entries)
-			break;
-		if (in_sched_functions(state.ip))
-			continue;
-		if (trace->skip > 0)
-			trace->skip--;
-		else
-			trace->entries[trace->nr_entries++] = state.ip;
-	}
-}
-EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+	unwind_for_each_frame(&state, task, NULL, 0) {
+		if (state.stack_info.type != STACK_TYPE_TASK)
+			return -EINVAL;
 
-void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
-{
-	struct unwind_state state;
+		if (state.regs)
+			return -EINVAL;
 
-	unwind_for_each_frame(&state, current, regs, 0) {
-		if (trace->nr_entries >= trace->max_entries)
-			break;
-		if (trace->skip > 0)
-			trace->skip--;
-		else
-			trace->entries[trace->nr_entries++] = state.ip;
+		addr = unwind_get_return_address(&state);
+		if (!addr)
+			return -EINVAL;
+
+#ifdef CONFIG_KPROBES
+		/*
+		 * Mark stacktraces with kretprobed functions on them
+		 * as unreliable.
+		 */
+		if (state.ip == (unsigned long)kretprobe_trampoline)
+			return -EINVAL;
+#endif
+
+		if (!consume_entry(cookie, addr, false))
+			return -EINVAL;
 	}
+
+	/* Check for stack corruption */
+	if (unwind_error(&state))
+		return -EINVAL;
+	return 0;
 }
-EXPORT_SYMBOL_GPL(save_stack_trace_regs);