3 files changed, 52 insertions, 8 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 37a0aeaf89e7..b0e641793be4 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -407,7 +407,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 
 	set_vm_flush_reset_perms(trampoline);
 
-	set_memory_ro((unsigned long)trampoline, npages);
+	if (likely(system_state != SYSTEM_BOOTING))
+		set_memory_ro((unsigned long)trampoline, npages);
 	set_memory_x((unsigned long)trampoline, npages);
 	return (unsigned long)trampoline;
 fail:
@@ -415,6 +416,32 @@ fail:
 	return 0;
 }
 
+void set_ftrace_ops_ro(void)
+{
+	struct ftrace_ops *ops;
+	unsigned long start_offset;
+	unsigned long end_offset;
+	unsigned long npages;
+	unsigned long size;
+
+	do_for_each_ftrace_op(ops, ftrace_ops_list) {
+		if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
+			continue;
+
+		if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
+			start_offset = (unsigned long)ftrace_regs_caller;
+			end_offset = (unsigned long)ftrace_regs_caller_end;
+		} else {
+			start_offset = (unsigned long)ftrace_caller;
+			end_offset = (unsigned long)ftrace_epilogue;
+		}
+		size = end_offset - start_offset;
+		size = size + RET_SIZE + sizeof(void *);
+		npages = DIV_ROUND_UP(size, PAGE_SIZE);
+		set_memory_ro((unsigned long)ops->trampoline, npages);
+	} while_for_each_ftrace_op(ops);
+}
+
 static unsigned long calc_trampoline_call_offset(bool save_regs)
 {
 	unsigned long start_offset;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 8c89e4d9ad28..2f24c334a938 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -266,6 +266,14 @@ static void notrace start_secondary(void *unused)
 
 	wmb();
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
+
+	/*
+	 * Prevent tail call to cpu_startup_entry() because the stack protector
+	 * guard has been changed a couple of function calls up, in
+	 * boot_init_stack_canary() and must not be checked before tail calling
+	 * another function.
+	 */
+	prevent_tail_call_optimization();
 }
 
 /**
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 5b0bd8581fe6..7f969b2d240f 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -320,12 +320,19 @@ EXPORT_SYMBOL_GPL(unwind_get_return_address);
 
 unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
 {
+	struct task_struct *task = state->task;
+
 	if (unwind_done(state))
 		return NULL;
 
 	if (state->regs)
 		return &state->regs->ip;
 
+	if (task != current && state->sp == task->thread.sp) {
+		struct inactive_task_frame *frame = (void *)task->thread.sp;
+		return &frame->ret_addr;
+	}
+
 	if (state->sp)
 		return (unsigned long *)state->sp - 1;
 
@@ -617,23 +624,23 @@ EXPORT_SYMBOL_GPL(unwind_next_frame);
 void __unwind_start(struct unwind_state *state, struct task_struct *task,
 		    struct pt_regs *regs, unsigned long *first_frame)
 {
-	if (!orc_init)
-		goto done;
-
 	memset(state, 0, sizeof(*state));
 	state->task = task;
 
+	if (!orc_init)
+		goto err;
+
 	/*
 	 * Refuse to unwind the stack of a task while it's executing on another
 	 * CPU.  This check is racy, but that's ok: the unwinder has other
 	 * checks to prevent it from going off the rails.
 	 */
 	if (task_on_another_cpu(task))
-		goto done;
+		goto err;
 
 	if (regs) {
 		if (user_mode(regs))
-			goto done;
+			goto the_end;
 
 		state->ip = regs->ip;
 		state->sp = regs->sp;
@@ -666,6 +673,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
 		 * generate some kind of backtrace if this happens.
 		 */
 		void *next_page = (void *)PAGE_ALIGN((unsigned long)state->sp);
+		state->error = true;
 		if (get_stack_info(next_page, state->task, &state->stack_info,
 				   &state->stack_mask))
 			return;
@@ -691,8 +699,9 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
 
 	return;
 
-done:
+err:
+	state->error = true;
+the_end:
 	state->stack_info.type = STACK_TYPE_UNKNOWN;
-	return;
 }
 EXPORT_SYMBOL_GPL(__unwind_start);