x86/dumpstack: Print registers for first stack frame

In the stack dump code, if the frame after the starting pt_regs is also
a regs frame, the registers don't get printed.  Fix that.

Reported-by: Andy Lutomirski <luto@amacapital.net>
Tested-by: Alexander Tsoy <alexander@tsoy.me>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toralf Förster <toralf.foerster@gmx.de>
Cc: stable@vger.kernel.org
Fixes: 4033ada53ff1 ("x86/dumpstack: Print any pt_regs found on the stack")
Link: http://lkml.kernel.org/r/396f84491d2f0ef64eda4217a2165f5712f6a115.1514736742.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index d0bb176a7261ae85c09580ec4dd103923ae0348a..afbecff161d162c11a82d0610ae406b910c3f791 100644 (file)
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -115,6 +115,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 
        unwind_start(&state, task, regs, stack);
        stack = stack ? : get_stack_pointer(task, regs);
+       regs = unwind_get_entry_regs(&state, &partial);
 
        /*
         * Iterate through the stacks, starting with the current stack pointer.
@@ -132,7 +133,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
         * - hardirq stack
         * - entry stack
         */
-       for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
+       for ( ; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
                const char *stack_name;
 
                if (get_stack_info(stack, task, &stack_info, &visit_mask)) {