[PATCH] irq_work: record irq_work_queue() call stack

[PATCH] irq_work: record irq_work_queue() call stack

[qiang.zhang]

From: Zqiang <qiang.zhang@windriver.com>

Add the irq_work_queue() call stack into the KASAN auxiliary
stack in order to improve KASAN reports. this will let us know
where the irq work be queued.

Signed-off-by: Zqiang <qiang.zhang@windriver.com>
---
 kernel/irq_work.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index e8da1e71583a..23a7a0ba1388 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -19,7 +19,7 @@
 #include <linux/notifier.h>
 #include <linux/smp.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);
@@ -70,6 +70,9 @@ bool irq_work_queue(struct irq_work *work)
 	if (!irq_work_claim(work))
 		return false;
 
+	/*record irq_work call stack in order to print it in KASAN reports*/
+	kasan_record_aux_stack(work);
+
 	/* Queue the entry and raise the IPI if needed. */
 	preempt_disable();
 	__irq_work_queue_local(work);
@@ -98,6 +101,8 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
 	if (!irq_work_claim(work))
 		return false;
 
+	kasan_record_aux_stack(work);
+
 	preempt_disable();
 	if (cpu != smp_processor_id()) {
 		/* Arch remote IPI send/receive backend aren't NMI safe */
-- 
2.17.1

Re: [PATCH] irq_work: record irq_work_queue() call stack

[Dmitry Vyukov]

On Wed, Mar 31, 2021 at 8:32 AM <qiang.zhang@windriver.com> wrote:
>
> From: Zqiang <qiang.zhang@windriver.com>
>
> Add the irq_work_queue() call stack into the KASAN auxiliary
> stack in order to improve KASAN reports. this will let us know
> where the irq work be queued.
>
> Signed-off-by: Zqiang <qiang.zhang@windriver.com>

Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

> ---
>  kernel/irq_work.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index e8da1e71583a..23a7a0ba1388 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -19,7 +19,7 @@
>  #include <linux/notifier.h>
>  #include <linux/smp.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);
> @@ -70,6 +70,9 @@ bool irq_work_queue(struct irq_work *work)
>         if (!irq_work_claim(work))
>                 return false;
>
> +       /*record irq_work call stack in order to print it in KASAN reports*/
> +       kasan_record_aux_stack(work);
> +
>         /* Queue the entry and raise the IPI if needed. */
>         preempt_disable();
>         __irq_work_queue_local(work);
> @@ -98,6 +101,8 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
>         if (!irq_work_claim(work))
>                 return false;
>
> +       kasan_record_aux_stack(work);
> +
>         preempt_disable();
>         if (cpu != smp_processor_id()) {
>                 /* Arch remote IPI send/receive backend aren't NMI safe */
> --
> 2.17.1
>

Re: [PATCH] irq_work: record irq_work_queue() call stack

[Andrey Konovalov]

On Wed, Mar 31, 2021 at 8:32 AM <qiang.zhang@windriver.com> wrote:
>
> From: Zqiang <qiang.zhang@windriver.com>
>
> Add the irq_work_queue() call stack into the KASAN auxiliary
> stack in order to improve KASAN reports. this will let us know
> where the irq work be queued.
>
> Signed-off-by: Zqiang <qiang.zhang@windriver.com>
> ---
>  kernel/irq_work.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index e8da1e71583a..23a7a0ba1388 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -19,7 +19,7 @@
>  #include <linux/notifier.h>
>  #include <linux/smp.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);
> @@ -70,6 +70,9 @@ bool irq_work_queue(struct irq_work *work)
>         if (!irq_work_claim(work))
>                 return false;
>
> +       /*record irq_work call stack in order to print it in KASAN reports*/
> +       kasan_record_aux_stack(work);
> +
>         /* Queue the entry and raise the IPI if needed. */
>         preempt_disable();
>         __irq_work_queue_local(work);
> @@ -98,6 +101,8 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
>         if (!irq_work_claim(work))
>                 return false;
>
> +       kasan_record_aux_stack(work);
> +
>         preempt_disable();
>         if (cpu != smp_processor_id()) {
>                 /* Arch remote IPI send/receive backend aren't NMI safe */
> --
> 2.17.1

Acked-by: Andrey Konovalov <andreyknvl@gmail.com>

Re: [PATCH] irq_work: record irq_work_queue() call stack

[Peter Zijlstra]

On Wed, Mar 31, 2021 at 02:32:02PM +0800, qiang.zhang@windriver.com wrote:

> @@ -70,6 +70,9 @@ bool irq_work_queue(struct irq_work *work)
>  	if (!irq_work_claim(work))
>  		return false;
>  
> +	/*record irq_work call stack in order to print it in KASAN reports*/
> +	kasan_record_aux_stack(work);
> +
>  	/* Queue the entry and raise the IPI if needed. */
>  	preempt_disable();
>  	__irq_work_queue_local(work);

Thanks for the Cc :/ Also NAK.

I shall go revert this instantly. KASAN is not NMI safe, while
irq_work_queue() is very carefully crafted to be exactly that.

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

[Peter Zijlstra]

On Tue, Jun 08, 2021 at 07:51:02PM +0200, Peter Zijlstra wrote:
> On Wed, Mar 31, 2021 at 02:32:02PM +0800, qiang.zhang@windriver.com wrote:
> 
> > @@ -70,6 +70,9 @@ bool irq_work_queue(struct irq_work *work)
> >  	if (!irq_work_claim(work))
> >  		return false;
> >  
> > +	/*record irq_work call stack in order to print it in KASAN reports*/
> > +	kasan_record_aux_stack(work);
> > +
> >  	/* Queue the entry and raise the IPI if needed. */
> >  	preempt_disable();
> >  	__irq_work_queue_local(work);
> 
> Thanks for the Cc :/ Also NAK.
> 
> I shall go revert this instantly. KASAN is not NMI safe, while
> irq_work_queue() is very carefully crafted to be exactly that.

The below goes in tip/perf/urgent ASAP.

---
Subject: irq_work: Make irq_work_queue() NMI-safe again
From: Peter Zijlstra <peterz@infradead.org>
Date: Tue Jun  8 19:54:15 CEST 2021

Someone carelessly put NMI unsafe code in irq_work_queue(), breaking
just about every single user. Also, someone has a terrible comment
style.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/irq_work.c |    3 ---
 1 file changed, 3 deletions(-)

--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -70,9 +70,6 @@ bool irq_work_queue(struct irq_work *wor
 	if (!irq_work_claim(work))
 		return false;
 
-	/*record irq_work call stack in order to print it in KASAN reports*/
-	kasan_record_aux_stack(work);
-
 	/* Queue the entry and raise the IPI if needed. */
 	preempt_disable();
 	__irq_work_queue_local(work);

[tip: perf/urgent] irq_work: Make irq_work_queue() NMI-safe again

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     dc6be79444d82d5b9d679c7d6bd77c672f1e28ca
Gitweb:        https://git.kernel.org/tip/dc6be79444d82d5b9d679c7d6bd77c672f1e28ca
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Tue, 08 Jun 2021 19:54:15 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 08 Jun 2021 20:03:59 +02:00

irq_work: Make irq_work_queue() NMI-safe again

Someone carelessly put NMI unsafe code in irq_work_queue(), breaking
just about every single user. Also, someone has a terrible comment
style.

Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YL+uBq8LzXXZsYVf@hirez.programming.kicks-ass.net
---
 kernel/irq_work.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 23a7a0b..db8c248 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -70,9 +70,6 @@ bool irq_work_queue(struct irq_work *work)
 	if (!irq_work_claim(work))
 		return false;
 
-	/*record irq_work call stack in order to print it in KASAN reports*/
-	kasan_record_aux_stack(work);
-
 	/* Queue the entry and raise the IPI if needed. */
 	preempt_disable();
 	__irq_work_queue_local(work);

[tip: perf/urgent] irq_work: Make irq_work_queue() NMI-safe again

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     156172a13ff0626d8e23276e741c7e2cb2f3b572
Gitweb:        https://git.kernel.org/tip/156172a13ff0626d8e23276e741c7e2cb2f3b572
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Tue, 08 Jun 2021 19:54:15 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 10 Jun 2021 10:00:08 +02:00

irq_work: Make irq_work_queue() NMI-safe again

Someone carelessly put NMI unsafe code in irq_work_queue(), breaking
just about every single user. Also, someone has a terrible comment
style.

Fixes: e2b5bcf9f5ba ("irq_work: record irq_work_queue() call stack")
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YL+uBq8LzXXZsYVf@hirez.programming.kicks-ass.net
---
 kernel/irq_work.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 23a7a0b..db8c248 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -70,9 +70,6 @@ bool irq_work_queue(struct irq_work *work)
 	if (!irq_work_claim(work))
 		return false;
 
-	/*record irq_work call stack in order to print it in KASAN reports*/
-	kasan_record_aux_stack(work);
-
 	/* Queue the entry and raise the IPI if needed. */
 	preempt_disable();
 	__irq_work_queue_local(work);