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Message-ID: <9c951fe6-d354-5870-e91b-83d8346ac162@intel.com>
Date: Wed, 27 Apr 2022 09:49:02 +0800
From: Jun Miao <jun.miao@...el.com>
To: <ryabinin.a.a@...il.com>, Dmitry Vyukov <dvyukov@...gle.com>
CC: <bigeasy@...utronix.de>, <qiang1.zhang@...el.com>,
<peterz@...radead.org>, <akpm@...ux-foundation.org>,
<andreyknvl@...il.com>, <ying.huang@...el.com>,
<akpm@...ux-foundation.org>, <kasan-dev@...glegroups.com>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] irq_work: Make irq_work_queue_on() NMI-safe again
Add To/Cc : KASAN/MEM , since I only used the scripts/get_maintainer.pl
to irq_work.c file.
Thanks
Jun Miao
On 2022/4/26 21:49, 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
> carafted to be exactly that.
> When unable CONFIG_SM 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" <ying.huang@...el.com>
> Signed-off-by: Jun Miao <jun.miao@...el.com>
> ---
> 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 */
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