2022-04-27 14:21:29

by Jun Miao

Subject: [PATCH] irq_work: Make irq_work_queue_on() NMI-safe again

We should not put NMI unsafe code in irq_work_queue_on().

The KASAN of kasan_record_aux_stack_noalloc() is not NMI safe. Because which
will call the spinlock. While the irq_work_queue_on() is also very carefully
carfted to be exactly that.
When unable CONFIG_SMP or local CPU, the irq_work_queue_on() is even same to
irq_work_queue(). So delete KASAN instantly.

Fixes: e2b5bcf9f5ba ("irq_work: record irq_work_queue() call stack")
Suggested by: "Huang, Ying" <[email protected]>
Signed-off-by: Jun Miao <[email protected]>
Acked-by: Marco Elver <[email protected]>
---
kernel/irq_work.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc4..e7f48aa8d8af 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -20,7 +20,6 @@
#include <linux/smp.h>
#include <linux/smpboot.h>
#include <asm/processor.h>
-#include <linux/kasan.h>

static DEFINE_PER_CPU(struct llist_head, raised_list);
static DEFINE_PER_CPU(struct llist_head, lazy_list);
@@ -137,8 +136,6 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
if (!irq_work_claim(work))
return false;

- kasan_record_aux_stack_noalloc(work);
-
preempt_disable();
if (cpu != smp_processor_id()) {
/* Arch remote IPI send/receive backend aren't NMI safe */
--
2.32.0

2022-04-27 14:28:16

by Jun Miao

Subject: Re: [PATCH] irq_work: Make irq_work_queue_on() NMI-safe again

Sorry, please ignore!


On 2022/4/27 21:50, Jun Miao wrote:
> We should not put NMI unsafe code in irq_work_queue_on().
>
> The KASAN of kasan_record_aux_stack_noalloc() is not NMI safe. Because which
> will call the spinlock. While the irq_work_queue_on() is also very carefully
> carfted to be exactly that.
> When unable CONFIG_SMP or local CPU, the irq_work_queue_on() is even same to
> irq_work_queue(). So delete KASAN instantly.
>
> Fixes: e2b5bcf9f5ba ("irq_work: record irq_work_queue() call stack")
> Suggested by: "Huang, Ying" <[email protected]>
> Signed-off-by: Jun Miao <[email protected]>
> Acked-by: Marco Elver <[email protected]>
> ---
> kernel/irq_work.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index 7afa40fe5cc4..e7f48aa8d8af 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -20,7 +20,6 @@
> #include <linux/smp.h>
> #include <linux/smpboot.h>
> #include <asm/processor.h>
> -#include <linux/kasan.h>
>
> static DEFINE_PER_CPU(struct llist_head, raised_list);
> static DEFINE_PER_CPU(struct llist_head, lazy_list);
> @@ -137,8 +136,6 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
> if (!irq_work_claim(work))
> return false;
>
> - kasan_record_aux_stack_noalloc(work);
> -
> preempt_disable();
> if (cpu != smp_processor_id()) {
> /* Arch remote IPI send/receive backend aren't NMI safe */