1 files changed, 39 insertions, 13 deletions

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index e9b9b5364393..cbedd724f48e 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -146,17 +146,15 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 {
         struct stackframe frame;
+        unsigned long irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
+        int skip;
 
         pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
 
         if (!tsk)
                 tsk = current;
 
-        if (regs) {
-                frame.fp = regs->regs[29];
-                frame.sp = regs->sp;
-                frame.pc = regs->pc;
-        } else if (tsk == current) {
+        if (tsk == current) {
                 frame.fp = (unsigned long)__builtin_frame_address(0);
                 frame.sp = current_stack_pointer;
                 frame.pc = (unsigned long)dump_backtrace;
@@ -168,21 +166,49 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
                 frame.sp = thread_saved_sp(tsk);
                 frame.pc = thread_saved_pc(tsk);
         }
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        frame.graph = tsk->curr_ret_stack;
+#endif
 
-        pr_emerg("Call trace:\n");
+        skip = !!regs;
+        printk("Call trace:\n");
         while (1) {
                 unsigned long where = frame.pc;
                 unsigned long stack;
                 int ret;
 
-                dump_backtrace_entry(where);
-                ret = unwind_frame(&frame);
+                /* skip until specified stack frame */
+                if (!skip) {
+                        dump_backtrace_entry(where);
+                } else if (frame.fp == regs->regs[29]) {
+                        skip = 0;
+                        /*
+                         * Mostly, this is the case where this function is
+                         * called in panic/abort. As exception handler's
+                         * stack frame does not contain the corresponding pc
+                         * at which an exception has taken place, use regs->pc
+                         * instead.
+                         */
+                        dump_backtrace_entry(regs->pc);
+                }
+                ret = unwind_frame(tsk, &frame);
                 if (ret < 0)
                         break;
                 stack = frame.sp;
-                if (in_exception_text(where))
+                if (in_exception_text(where)) {
+                        /*
+                         * If we switched to the irq_stack before calling this
+                         * exception handler, then the pt_regs will be on the
+                         * task stack. The easiest way to tell is if the large
+                         * pt_regs would overlap with the end of the irq_stack.
+                         */
+                        if (stack < irq_stack_ptr &&
+                            (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
+                                stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
+
                         dump_mem("", "Exception stack", stack,
                                  stack + sizeof(struct pt_regs), false);
+                }
         }
 }
 
@@ -456,22 +482,22 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 
 void __pte_error(const char *file, int line, unsigned long val)
 {
-        pr_crit("%s:%d: bad pte %016lx.\n", file, line, val);
+        pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
 }
 
 void __pmd_error(const char *file, int line, unsigned long val)
 {
-        pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val);
+        pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
 }
 
 void __pud_error(const char *file, int line, unsigned long val)
 {
-        pr_crit("%s:%d: bad pud %016lx.\n", file, line, val);
+        pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
 }
 
 void __pgd_error(const char *file, int line, unsigned long val)
 {
-        pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val);
+        pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
 }
 
 /* GENERIC_BUG traps */