* [PATCH v2] xtensa: improve stack dumping
@ 2019-11-08 0:44 Max Filippov
2019-11-12 9:49 ` Petr Mladek
0 siblings, 1 reply; 3+ messages in thread
From: Max Filippov @ 2019-11-08 0:44 UTC (permalink / raw)
To: linux-xtensa
Cc: Chris Zankel, linux-kernel, Dmitry Safonov, Petr Mladek,
Joe Perches, Max Filippov
Calculate printable stack size and use print_hex_dump instead of
opencoding it.
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>
---
Changes v1->v2:
- use print_hex_dump.
arch/xtensa/Kconfig.debug | 7 +++++++
arch/xtensa/kernel/traps.c | 24 ++++++++----------------
2 files changed, 15 insertions(+), 16 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..fe090ab1cab8 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -491,32 +491,24 @@ 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;
+ size_t len;
if (!sp)
sp = stack_pointer(task);
- stack = sp;
- pr_info("Stack:\n");
+ len = min((-(unsigned long)sp) & (THREAD_SIZE - 4),
+ kstack_depth_to_print * 4ul);
- for (i = 0; i < kstack_depth_to_print; i++) {
- if (kstack_end(sp))
- break;
- pr_cont(" %08lx", *sp++);
- if (i % 8 == 7)
- pr_cont("\n");
- }
- show_trace(task, stack);
+ pr_info("Stack:\n");
+ print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE, 32, 4,
+ sp, len, false);
+ show_trace(task, sp);
}
DEFINE_SPINLOCK(die_lock);
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] xtensa: improve stack dumping
2019-11-08 0:44 [PATCH v2] xtensa: improve stack dumping Max Filippov
@ 2019-11-12 9:49 ` Petr Mladek
2019-11-12 16:23 ` Max Filippov
0 siblings, 1 reply; 3+ messages in thread
From: Petr Mladek @ 2019-11-12 9:49 UTC (permalink / raw)
To: Max Filippov
Cc: linux-xtensa, Chris Zankel, linux-kernel, Dmitry Safonov, Joe Perches
On Thu 2019-11-07 16:44:48, Max Filippov wrote:
> Calculate printable stack size and use print_hex_dump instead of
> opencoding it.
> Make size of stack dump configurable.
> Drop extra newline output in show_trace as its output format does not
> depend on CONFIG_KALLSYMS.
> 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.
I would split this into separate patch.
> diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
> index 4a6c495ce9b6..fe090ab1cab8 100644
> --- a/arch/xtensa/kernel/traps.c
> +++ b/arch/xtensa/kernel/traps.c
> @@ -491,32 +491,24 @@ 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;
> + size_t len;
>
> if (!sp)
> sp = stack_pointer(task);
> - stack = sp;
>
> - pr_info("Stack:\n");
> + len = min((-(unsigned long)sp) & (THREAD_SIZE - 4),
> + kstack_depth_to_print * 4ul);
I would replace the hardcoded 4 with sizeof(void *).
>
> - for (i = 0; i < kstack_depth_to_print; i++) {
> - if (kstack_end(sp))
> - break;
> - pr_cont(" %08lx", *sp++);
> - if (i % 8 == 7)
> - pr_cont("\n");
> - }
> - show_trace(task, stack);
> + pr_info("Stack:\n");
> + print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE, 32, 4,
> + sp, len, false);
> + show_trace(task, sp);
> }
The conversion looks fine to me. It is up to you (as a maintainer)
what you do with the above proposal for two cosmetic changes ;-)
Either way, feel free to use:
Reviewed-by: Petr Mladek <pmladek@suse.com>
Best Regards,
Petr
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] xtensa: improve stack dumping
2019-11-12 9:49 ` Petr Mladek
@ 2019-11-12 16:23 ` Max Filippov
0 siblings, 0 replies; 3+ messages in thread
From: Max Filippov @ 2019-11-12 16:23 UTC (permalink / raw)
To: Petr Mladek
Cc: open list:TENSILICA XTENSA PORT (xtensa),
Chris Zankel, LKML, Dmitry Safonov, Joe Perches
On Tue, Nov 12, 2019 at 1:49 AM Petr Mladek <pmladek@suse.com> wrote:
>
> On Thu 2019-11-07 16:44:48, Max Filippov wrote:
> > Calculate printable stack size and use print_hex_dump instead of
> > opencoding it.
> > Make size of stack dump configurable.
> > Drop extra newline output in show_trace as its output format does not
> > depend on CONFIG_KALLSYMS.
>
> > 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.
>
> I would split this into separate patch.
Sure, I'll split it out.
> > diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
> > index 4a6c495ce9b6..fe090ab1cab8 100644
> > --- a/arch/xtensa/kernel/traps.c
> > +++ b/arch/xtensa/kernel/traps.c
> > @@ -491,32 +491,24 @@ 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;
> > + size_t len;
> >
> > if (!sp)
> > sp = stack_pointer(task);
> > - stack = sp;
> >
> > - pr_info("Stack:\n");
> > + len = min((-(unsigned long)sp) & (THREAD_SIZE - 4),
> > + kstack_depth_to_print * 4ul);
>
> I would replace the hardcoded 4 with sizeof(void *).
It's not necessarily pointers, more like register-wide entries
on the stack. Ok, I guess I'll give it a name.
> > - for (i = 0; i < kstack_depth_to_print; i++) {
> > - if (kstack_end(sp))
> > - break;
> > - pr_cont(" %08lx", *sp++);
> > - if (i % 8 == 7)
> > - pr_cont("\n");
> > - }
> > - show_trace(task, stack);
> > + pr_info("Stack:\n");
> > + print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE, 32, 4,
> > + sp, len, false);
> > + show_trace(task, sp);
> > }
>
> The conversion looks fine to me. It is up to you (as a maintainer)
> what you do with the above proposal for two cosmetic changes ;-)
> Either way, feel free to use:
>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
Thanks for the review.
-- Max
^ permalink raw reply [flat|nested] 3+ messages in thread
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