parisc: Stop unwinding at start of stack

Check stack pointer if we are reaching the stack end and stop unwinding if we do. This fixes early backtraces and avoids showing unrealistic call stacks. Signed-off-by: Helge Deller <[email protected]>
kyagi · Sep 22, 2017 · e77900a · e77900a
1 parent 432654d
commit e77900a
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/kallsyms.h>
 #include <linux/sort.h>
+#include <linux/sched.h>
 
 #include <linux/uaccess.h>
 #include <asm/assembly.h>
@@ -279,6 +280,17 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
 
 			info->prev_sp = sp - 64;
 			info->prev_ip = 0;
+
+			/* The stack is at the end inside the thread_union
+			 * struct. If we reach data, we have reached the
+			 * beginning of the stack and should stop unwinding. */
+			if (info->prev_sp >= (unsigned long) task_thread_info(info->t) &&
+			    info->prev_sp < ((unsigned long) task_thread_info(info->t)
+						+ THREAD_SZ_ALGN)) {
+				info->prev_sp = 0;
+				break;
+			}
+
 			if (get_user(tmp, (unsigned long *)(info->prev_sp - RP_OFFSET))) 
 				break;
 			info->prev_ip = tmp;