arm/stacktrace: Remove the pointless ULONG_MAX marker

Terminating the last trace entry with ULONG_MAX is a completely pointless
exercise and none of the consumers can rely on it because it's
inconsistently implemented across architectures. In fact quite some of the
callers remove the entry and adjust stack_trace.nr_entries afterwards.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lkml.kernel.org/r/20190410103643.843075256@linutronix.de

diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index a56e7c856ab5648995888ae5f47c5d1ab23b08bf..86870f40f9a07558877d1d7dba098ad5926c4bbf 100644 (file)
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -115,8 +115,6 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
                 * running on another CPU?  For now, ignore it as we
                 * can't guarantee we won't explode.
                 */
-               if (trace->nr_entries < trace->max_entries)
-                       trace->entries[trace->nr_entries++] = ULONG_MAX;
                return;
 #else
                frame.fp = thread_saved_fp(tsk);
@@ -134,8 +132,6 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
        }
 
        walk_stackframe(&frame, save_trace, &data);
-       if (trace->nr_entries < trace->max_entries)
-               trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
 
 void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
@@ -153,8 +149,6 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
        frame.pc = regs->ARM_pc;
 
        walk_stackframe(&frame, save_trace, &data);
-       if (trace->nr_entries < trace->max_entries)
-               trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
 
 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)