From: liu chuansheng <[email protected]>
Subject: [PATCH] x86_dump_trace: avoiding endless " <IRQ> " is printed
Found the case that endless " <IRQ> " printing in dump_trace,
and no real meaningful stack traces are output, so there should
be one rare case that possibly context->previous_esp = context or
other cases.
The endless " <IRQ> " is as below:
...
[ 82.215244,0] <IRQ>
[ 82.215399,0] <IRQ>
[ 82.215554,0] <IRQ>
[ 82.215710,0] <IRQ>
[ 82.215865,0] <IRQ>
[ 82.216022,0] <IRQ>
[ 82.216178,0] <IRQ>
[ 82.216333,0] <IRQ>
[ 82.216488,0] <IRQ>
[ 82.216643,0] <IRQ>
[ 82.216798,0] <IRQ>
[ 82.216953,0] <IRQ>
...
This patch aim is:
1/ Limiting the " <IRQ> " outputing, currently the max IRQ contexts
is 2(softirq+harirq combination);
2/ When the max IRQ contexts 2 is reached, print the context content
to confirm;
Change-Id: I6d72aa71c4c5ff8f9e6ae133b3f6bfec8887750d
Signed-off-by: liu chuansheng <[email protected]>
---
arch/x86/kernel/dumpstack_32.c | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 1038a41..410fa38 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -22,6 +22,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
const struct stacktrace_ops *ops, void *data)
{
int graph = 0;
+ int dump_irq_count = 0;
if (!task)
task = current;
@@ -47,8 +48,18 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
stack = (unsigned long *)context->previous_esp;
if (!stack)
break;
+
+ if (dump_irq_count > 2) {
+ pr_warn("break multi-IRQ print,"
+ "context=%p, stack=%p\n",
+ context,
+ stack);
+ break;
+ }
+
if (ops->stack(data, "IRQ") < 0)
break;
+ dump_irq_count++;
touch_nmi_watchdog();
}
}
--
1.7.0.4
Do you think we should add the same change to dumpstack_64.c too.
Looks like you addressed Alan's comments already (i.e. use of unlikely not needed, us %p, and use pr_warn instead of printk)
--mark
> -----Original Message-----
> From: Liu, Chuansheng
> Sent: Sunday, August 26, 2012 6:56 PM
> To: '[email protected]' ([email protected])
> Cc: [email protected]; Gross, Mark; [email protected]
> Subject: [PATCH RESEND] x86_dump_trace: avoiding endless " <IRQ> " is
> printed
>
> From: liu chuansheng <[email protected]>
> Subject: [PATCH] x86_dump_trace: avoiding endless " <IRQ> " is printed
>
> Found the case that endless " <IRQ> " printing in dump_trace, and no real
> meaningful stack traces are output, so there should be one rare case that
> possibly context->previous_esp = context or other cases.
>
> The endless " <IRQ> " is as below:
> ...
> [ 82.215244,0] <IRQ>
> [ 82.215399,0] <IRQ>
> [ 82.215554,0] <IRQ>
> [ 82.215710,0] <IRQ>
> [ 82.215865,0] <IRQ>
> [ 82.216022,0] <IRQ>
> [ 82.216178,0] <IRQ>
> [ 82.216333,0] <IRQ>
> [ 82.216488,0] <IRQ>
> [ 82.216643,0] <IRQ>
> [ 82.216798,0] <IRQ>
> [ 82.216953,0] <IRQ>
> ...
>
> This patch aim is:
> 1/ Limiting the " <IRQ> " outputing, currently the max IRQ contexts is
> 2(softirq+harirq combination); 2/ When the max IRQ contexts 2 is reached,
> print the context content to confirm;
>
> Change-Id: I6d72aa71c4c5ff8f9e6ae133b3f6bfec8887750d
> Signed-off-by: liu chuansheng <[email protected]>
> ---
> arch/x86/kernel/dumpstack_32.c | 11 +++++++++++
> 1 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/dumpstack_32.c
> b/arch/x86/kernel/dumpstack_32.c index 1038a41..410fa38 100644
> --- a/arch/x86/kernel/dumpstack_32.c
> +++ b/arch/x86/kernel/dumpstack_32.c
> @@ -22,6 +22,7 @@ void dump_trace(struct task_struct *task, struct pt_regs
> *regs,
> const struct stacktrace_ops *ops, void *data) {
> int graph = 0;
> + int dump_irq_count = 0;
>
> if (!task)
> task = current;
> @@ -47,8 +48,18 @@ void dump_trace(struct task_struct *task, struct
> pt_regs *regs,
> stack = (unsigned long *)context->previous_esp;
> if (!stack)
> break;
> +
> + if (dump_irq_count > 2) {
> + pr_warn("break multi-IRQ print,"
> + "context=%p, stack=%p\n",
> + context,
> + stack);
> + break;
> + }
> +
> if (ops->stack(data, "IRQ") < 0)
> break;
> + dump_irq_count++;
> touch_nmi_watchdog();
> }
> }
> --
> 1.7.0.4
> Do you think we should add the same change to dumpstack_64.c too.
Feels dumpstack_64.c has different with dumpstack_32 which just has three types stacks for normal thread, hardirq and softirq,
so just want to use this patch to cover x86_32 case and it is the real case I meet also, thanks.
> -----Original Message-----
> From: Gross, Mark
> Sent: Monday, August 27, 2012 11:50 PM
> To: Liu, Chuansheng; '[email protected]'
> ([email protected])
> Cc: [email protected]; [email protected]; Pan, Jacob jun
> Subject: RE: [PATCH RESEND] x86_dump_trace: avoiding endless " <IRQ> " is
> printed
>
> Do you think we should add the same change to dumpstack_64.c too.
>
> Looks like you addressed Alan's comments already (i.e. use of unlikely not
> needed, us %p, and use pr_warn instead of printk)
>
> --mark
>
> > -----Original Message-----
> > From: Liu, Chuansheng
> > Sent: Sunday, August 26, 2012 6:56 PM
> > To: '[email protected]' ([email protected])
> > Cc: [email protected]; Gross, Mark; [email protected]
> > Subject: [PATCH RESEND] x86_dump_trace: avoiding endless " <IRQ> " is
> > printed
> >
> > From: liu chuansheng <[email protected]>
> > Subject: [PATCH] x86_dump_trace: avoiding endless " <IRQ> " is printed
> >
> > Found the case that endless " <IRQ> " printing in dump_trace, and no
> > real meaningful stack traces are output, so there should be one rare
> > case that possibly context->previous_esp = context or other cases.
> >
> > The endless " <IRQ> " is as below:
> > ...
> > [ 82.215244,0] <IRQ>
> > [ 82.215399,0] <IRQ>
> > [ 82.215554,0] <IRQ>
> > [ 82.215710,0] <IRQ>
> > [ 82.215865,0] <IRQ>
> > [ 82.216022,0] <IRQ>
> > [ 82.216178,0] <IRQ>
> > [ 82.216333,0] <IRQ>
> > [ 82.216488,0] <IRQ>
> > [ 82.216643,0] <IRQ>
> > [ 82.216798,0] <IRQ>
> > [ 82.216953,0] <IRQ>
> > ...
> >
> > This patch aim is:
> > 1/ Limiting the " <IRQ> " outputing, currently the max IRQ contexts is
> > 2(softirq+harirq combination); 2/ When the max IRQ contexts 2 is
> > reached, print the context content to confirm;
> >
> > Change-Id: I6d72aa71c4c5ff8f9e6ae133b3f6bfec8887750d
> > Signed-off-by: liu chuansheng <[email protected]>
> > ---
> > arch/x86/kernel/dumpstack_32.c | 11 +++++++++++
> > 1 files changed, 11 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/x86/kernel/dumpstack_32.c
> > b/arch/x86/kernel/dumpstack_32.c index 1038a41..410fa38 100644
> > --- a/arch/x86/kernel/dumpstack_32.c
> > +++ b/arch/x86/kernel/dumpstack_32.c
> > @@ -22,6 +22,7 @@ void dump_trace(struct task_struct *task, struct
> > pt_regs *regs,
> > const struct stacktrace_ops *ops, void *data) {
> > int graph = 0;
> > + int dump_irq_count = 0;
> >
> > if (!task)
> > task = current;
> > @@ -47,8 +48,18 @@ void dump_trace(struct task_struct *task, struct
> > pt_regs *regs,
> > stack = (unsigned long *)context->previous_esp;
> > if (!stack)
> > break;
> > +
> > + if (dump_irq_count > 2) {
> > + pr_warn("break multi-IRQ print,"
> > + "context=%p, stack=%p\n",
> > + context,
> > + stack);
> > + break;
> > + }
> > +
> > if (ops->stack(data, "IRQ") < 0)
> > break;
> > + dump_irq_count++;
> > touch_nmi_watchdog();
> > }
> > }
> > --
> > 1.7.0.4