[PATCH v3 09/13] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp

[Andy Lutomirski <luto@kernel.org>]

The comment suggests that show_stack(NULL, NULL) should backtrace
the current context, but the code doesn't match the comment.  If
regs are given, start the "Stack:" hexdump at regs->sp.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/kernel/dumpstack_32.c | 4 +++-
 arch/x86/kernel/dumpstack_64.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 464ffd69b92e..91069ebe3c87 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -98,7 +98,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	int i;
 
 	if (sp == NULL) {
-		if (task)
+		if (regs)
+			sp = (unsigned long *)regs->sp;
+		else if (task)
 			sp = (unsigned long *)task->thread.sp;
 		else
 			sp = (unsigned long *)&sp;
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 5f1c6266eb30..603356a5597a 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -266,7 +266,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	 * back trace for this cpu:
 	 */
 	if (sp == NULL) {
-		if (task)
+		if (regs)
+			sp = (unsigned long *)regs->sp;
+		else if (task)
 			sp = (unsigned long *)task->thread.sp;
 		else
 			sp = (unsigned long *)&sp;
-- 
2.5.5