1 files changed, 68 insertions, 84 deletions

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index fdd0c6430e5a..ee117fcf46ed 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -4,82 +4,78 @@
  *  Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
  */
 #include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task_stack.h>
 #include <linux/stacktrace.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/uaccess.h>
 #include <asm/stacktrace.h>
+#include <asm/unwind.h>
 
-static int save_stack_stack(void *data, char *name)
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+		     struct task_struct *task, struct pt_regs *regs)
 {
-	return 0;
-}
+	struct unwind_state state;
+	unsigned long addr;
 
-static void
-__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
-{
-	struct stack_trace *trace = data;
-#ifdef CONFIG_FRAME_POINTER
-	if (!reliable)
-		return;
-#endif
-	if (nosched && in_sched_functions(addr))
+	if (regs && !consume_entry(cookie, regs->ip))
 		return;
-	if (trace->skip > 0) {
-		trace->skip--;
-		return;
-	}
-	if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = addr;
-}
 
-static void save_stack_address(void *data, unsigned long addr, int reliable)
-{
-	return __save_stack_address(data, addr, reliable, false);
+	for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
+	     unwind_next_frame(&state)) {
+		addr = unwind_get_return_address(&state);
+		if (!addr || !consume_entry(cookie, addr))
+			break;
+	}
 }
 
-static void
-save_stack_address_nosched(void *data, unsigned long addr, int reliable)
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+			     void *cookie, struct task_struct *task)
 {
-	return __save_stack_address(data, addr, reliable, true);
-}
+	struct unwind_state state;
+	struct pt_regs *regs;
+	unsigned long addr;
+
+	for (unwind_start(&state, task, NULL, NULL);
+	     !unwind_done(&state) && !unwind_error(&state);
+	     unwind_next_frame(&state)) {
+
+		regs = unwind_get_entry_regs(&state, NULL);
+		if (regs) {
+			/* Success path for user tasks */
+			if (user_mode(regs))
+				return 0;
+
+			/*
+			 * Kernel mode registers on the stack indicate an
+			 * in-kernel interrupt or exception (e.g., preemption
+			 * or a page fault), which can make frame pointers
+			 * unreliable.
+			 */
+			if (IS_ENABLED(CONFIG_FRAME_POINTER))
+				return -EINVAL;
+		}
 
-static const struct stacktrace_ops save_stack_ops = {
-	.stack		= save_stack_stack,
-	.address	= save_stack_address,
-	.walk_stack	= print_context_stack,
-};
+		addr = unwind_get_return_address(&state);
 
-static const struct stacktrace_ops save_stack_ops_nosched = {
-	.stack		= save_stack_stack,
-	.address	= save_stack_address_nosched,
-	.walk_stack	= print_context_stack,
-};
+		/*
+		 * A NULL or invalid return address probably means there's some
+		 * generated code which __kernel_text_address() doesn't know
+		 * about.
+		 */
+		if (!addr)
+			return -EINVAL;
 
-/*
- * Save stack-backtrace addresses into a stack_trace buffer.
- */
-void save_stack_trace(struct stack_trace *trace)
-{
-	dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
-	if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = ULONG_MAX;
-}
-EXPORT_SYMBOL_GPL(save_stack_trace);
+		if (!consume_entry(cookie, addr))
+			return -EINVAL;
+	}
 
-void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
-{
-	dump_trace(current, regs, NULL, 0, &save_stack_ops, trace);
-	if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = ULONG_MAX;
-}
+	/* Check for stack corruption */
+	if (unwind_error(&state))
+		return -EINVAL;
 
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
-{
-	dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
-	if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = ULONG_MAX;
+	return 0;
 }
-EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
 
 /* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
 
@@ -89,31 +85,33 @@ struct stack_frame_user {
 };
 
 static int
-copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
+copy_stack_frame(const struct stack_frame_user __user *fp,
+		 struct stack_frame_user *frame)
 {
 	int ret;
 
-	if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+	if (!__access_ok(fp, sizeof(*frame)))
 		return 0;
 
 	ret = 1;
 	pagefault_disable();
-	if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+	if (__get_user(frame->next_fp, &fp->next_fp) ||
+	    __get_user(frame->ret_addr, &fp->ret_addr))
 		ret = 0;
 	pagefault_enable();
 
 	return ret;
 }
 
-static inline void __save_stack_trace_user(struct stack_trace *trace)
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+			  const struct pt_regs *regs)
 {
-	const struct pt_regs *regs = task_pt_regs(current);
 	const void __user *fp = (const void __user *)regs->bp;
 
-	if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = regs->ip;
+	if (!consume_entry(cookie, regs->ip))
+		return;
 
-	while (trace->nr_entries < trace->max_entries) {
+	while (1) {
 		struct stack_frame_user frame;
 
 		frame.next_fp = NULL;
@@ -122,25 +120,11 @@ static inline void __save_stack_trace_user(struct stack_trace *trace)
 			break;
 		if ((unsigned long)fp < regs->sp)
 			break;
-		if (frame.ret_addr) {
-			trace->entries[trace->nr_entries++] =
-				frame.ret_addr;
-		}
-		if (fp == frame.next_fp)
+		if (!frame.ret_addr)
+			break;
+		if (!consume_entry(cookie, frame.ret_addr))
 			break;
 		fp = frame.next_fp;
 	}
 }
 
-void save_stack_trace_user(struct stack_trace *trace)
-{
-	/*
-	 * Trace user stack if we are not a kernel thread
-	 */
-	if (current->mm) {
-		__save_stack_trace_user(trace);
-	}
-	if (trace->nr_entries < trace->max_entries)
-		trace->entries[trace->nr_entries++] = ULONG_MAX;
-}
-