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Subject[PATCH] xtensa: improve stack dumping
Date
Collect whole stack dump lines in a buffer and print the whole buffer
when it's ready with pr_info instead of pr_cont. This makes stack dump
lines consistent in SMP case and relies less on pr_cont/printk
differences related to timestamps.
Make size of stack dump configurable.
Drop extra newline output in show_trace as its output format does not
depend on CONFIG_KALLSYMS.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
arch/xtensa/Kconfig.debug | 7 +++++++
arch/xtensa/kernel/traps.c | 12 ++++++------
2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/arch/xtensa/Kconfig.debug b/arch/xtensa/Kconfig.debug
index 39de98e20018..83cc8d12fa0e 100644
--- a/arch/xtensa/Kconfig.debug
+++ b/arch/xtensa/Kconfig.debug
@@ -31,3 +31,10 @@ config S32C1I_SELFTEST
It is easy to make wrong hardware configuration, this test should catch it early.

Say 'N' on stable hardware.
+
+config PRINT_STACK_DEPTH
+ int "Stack depth to print" if DEBUG_KERNEL
+ default 64
+ help
+ This option allows you to set the stack depth that the kernel
+ prints in stack traces.
diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index 4a6c495ce9b6..b0c952652c73 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -491,17 +491,15 @@ void show_trace(struct task_struct *task, unsigned long *sp)

pr_info("Call Trace:\n");
walk_stackframe(sp, show_trace_cb, NULL);
-#ifndef CONFIG_KALLSYMS
- pr_cont("\n");
-#endif
}

-static int kstack_depth_to_print = 24;
+static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;

void show_stack(struct task_struct *task, unsigned long *sp)
{
int i = 0;
unsigned long *stack;
+ char buf[9 * 8 + 1];

if (!sp)
sp = stack_pointer(task);
@@ -512,10 +510,12 @@ void show_stack(struct task_struct *task, unsigned long *sp)
for (i = 0; i < kstack_depth_to_print; i++) {
if (kstack_end(sp))
break;
- pr_cont(" %08lx", *sp++);
+ sprintf(buf + (i % 8) * 9, " %08lx", *sp++);
if (i % 8 == 7)
- pr_cont("\n");
+ pr_info("%s\n", buf);
}
+ if (i % 8)
+ pr_info("%s\n", buf);
show_trace(task, stack);
}

--
2.20.1
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