* [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack
@ 2022-08-15 12:47 Qi Zheng
2022-08-26 4:16 ` Qi Zheng
2022-09-08 18:34 ` Catalin Marinas
0 siblings, 2 replies; 6+ messages in thread
From: Qi Zheng @ 2022-08-15 12:47 UTC (permalink / raw)
To: will, arnd, catalin.marinas, mark.rutland
Cc: linux-arm-kernel, linux-kernel, Qi Zheng
Currently arm64 supports per-CPU IRQ stack, but softirqs
are still handled in the task context.
Since any call to local_bh_enable() at any level in the task's
call stack may trigger a softirq processing run, which could
potentially cause a task stack overflow if the combined stack
footprints exceed the stack's size, let's run these softirqs
on the IRQ stack as well.
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Will Deacon <will@kernel.org>
---
v2: https://lore.kernel.org/lkml/20220802065325.39740-1-zhengqi.arch@bytedance.com/
v1: https://lore.kernel.org/lkml/20220708094950.41944-1-zhengqi.arch@bytedance.com/
RFC: https://lore.kernel.org/lkml/20220707110511.52129-1-zhengqi.arch@bytedance.com/
Changelog in v2 -> v3:
- rebase onto the v6.0-rc1
Changelog in v1 -> v2:
- temporarily discard [PATCH v1 2/2] to allow this patch to be merged first
- rebase onto the v5.19
- collect Reviewed-by and Acked-by
Changelog in RFC -> v1:
- fix conflicts with commit f2c5092190f2 ("arch/*: Disable softirq stacks on PREEMPT_RT.")
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/irq.c | 13 +++++++++++++
2 files changed, 14 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 571cc234d0b3..ee92f5887cf6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -230,6 +230,7 @@ config ARM64
select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
select TRACE_IRQFLAGS_SUPPORT
select TRACE_IRQFLAGS_NMI_SUPPORT
+ select HAVE_SOFTIRQ_ON_OWN_STACK
help
ARM 64-bit (AArch64) Linux support.
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index bda49430c9ea..c36ad20a52f3 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -22,6 +22,7 @@
#include <linux/vmalloc.h>
#include <asm/daifflags.h>
#include <asm/vmap_stack.h>
+#include <asm/exception.h>
/* Only access this in an NMI enter/exit */
DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
@@ -71,6 +72,18 @@ static void init_irq_stacks(void)
}
#endif
+#ifndef CONFIG_PREEMPT_RT
+static void ____do_softirq(struct pt_regs *regs)
+{
+ __do_softirq();
+}
+
+void do_softirq_own_stack(void)
+{
+ call_on_irq_stack(NULL, ____do_softirq);
+}
+#endif
+
static void default_handle_irq(struct pt_regs *regs)
{
panic("IRQ taken without a root IRQ handler\n");
--
2.20.1
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack
2022-08-15 12:47 [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack Qi Zheng
@ 2022-08-26 4:16 ` Qi Zheng
2022-09-07 7:04 ` Qi Zheng
2022-09-08 18:34 ` Catalin Marinas
1 sibling, 1 reply; 6+ messages in thread
From: Qi Zheng @ 2022-08-26 4:16 UTC (permalink / raw)
To: will
Cc: linux-arm-kernel, linux-kernel, Arnd Bergmann, Catalin Marinas,
Mark Rutland
On 2022/8/15 20:47, Qi Zheng wrote:
> Currently arm64 supports per-CPU IRQ stack, but softirqs
> are still handled in the task context.
>
> Since any call to local_bh_enable() at any level in the task's
> call stack may trigger a softirq processing run, which could
> potentially cause a task stack overflow if the combined stack
> footprints exceed the stack's size, let's run these softirqs
> on the IRQ stack as well.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Will Deacon <will@kernel.org>
> ---
> v2: https://lore.kernel.org/lkml/20220802065325.39740-1-zhengqi.arch@bytedance.com/
> v1: https://lore.kernel.org/lkml/20220708094950.41944-1-zhengqi.arch@bytedance.com/
> RFC: https://lore.kernel.org/lkml/20220707110511.52129-1-zhengqi.arch@bytedance.com/
>
> Changelog in v2 -> v3:
> - rebase onto the v6.0-rc1
Gentle ping.
Thanks,
Qi
>
> Changelog in v1 -> v2:
> - temporarily discard [PATCH v1 2/2] to allow this patch to be merged first
> - rebase onto the v5.19
> - collect Reviewed-by and Acked-by
>
> Changelog in RFC -> v1:
> - fix conflicts with commit f2c5092190f2 ("arch/*: Disable softirq stacks on PREEMPT_RT.")
>
> arch/arm64/Kconfig | 1 +
> arch/arm64/kernel/irq.c | 13 +++++++++++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 571cc234d0b3..ee92f5887cf6 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -230,6 +230,7 @@ config ARM64
> select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
> select TRACE_IRQFLAGS_SUPPORT
> select TRACE_IRQFLAGS_NMI_SUPPORT
> + select HAVE_SOFTIRQ_ON_OWN_STACK
> help
> ARM 64-bit (AArch64) Linux support.
>
> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
> index bda49430c9ea..c36ad20a52f3 100644
> --- a/arch/arm64/kernel/irq.c
> +++ b/arch/arm64/kernel/irq.c
> @@ -22,6 +22,7 @@
> #include <linux/vmalloc.h>
> #include <asm/daifflags.h>
> #include <asm/vmap_stack.h>
> +#include <asm/exception.h>
>
> /* Only access this in an NMI enter/exit */
> DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
> @@ -71,6 +72,18 @@ static void init_irq_stacks(void)
> }
> #endif
>
> +#ifndef CONFIG_PREEMPT_RT
> +static void ____do_softirq(struct pt_regs *regs)
> +{
> + __do_softirq();
> +}
> +
> +void do_softirq_own_stack(void)
> +{
> + call_on_irq_stack(NULL, ____do_softirq);
> +}
> +#endif
> +
> static void default_handle_irq(struct pt_regs *regs)
> {
> panic("IRQ taken without a root IRQ handler\n");
--
Thanks,
Qi
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack
2022-08-26 4:16 ` Qi Zheng
@ 2022-09-07 7:04 ` Qi Zheng
2022-09-07 13:34 ` Will Deacon
0 siblings, 1 reply; 6+ messages in thread
From: Qi Zheng @ 2022-09-07 7:04 UTC (permalink / raw)
To: will
Cc: linux-arm-kernel, linux-kernel, Arnd Bergmann, Catalin Marinas,
Mark Rutland
On 2022/8/26 12:16, Qi Zheng wrote:
>
>
> On 2022/8/15 20:47, Qi Zheng wrote:
>> Currently arm64 supports per-CPU IRQ stack, but softirqs
>> are still handled in the task context.
>>
>> Since any call to local_bh_enable() at any level in the task's
>> call stack may trigger a softirq processing run, which could
>> potentially cause a task stack overflow if the combined stack
>> footprints exceed the stack's size, let's run these softirqs
>> on the IRQ stack as well.
>>
>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
>> Acked-by: Will Deacon <will@kernel.org>
>> ---
>> v2:
>> https://lore.kernel.org/lkml/20220802065325.39740-1-zhengqi.arch@bytedance.com/
>> v1:
>> https://lore.kernel.org/lkml/20220708094950.41944-1-zhengqi.arch@bytedance.com/
>> RFC:
>> https://lore.kernel.org/lkml/20220707110511.52129-1-zhengqi.arch@bytedance.com/
>>
>> Changelog in v2 -> v3:
>> - rebase onto the v6.0-rc1
Hi Will,
Are we good to merge this patch? Or if there is anything else I need to
do, please let me know. :)
Looking forward to your reply.
Thanks,
Qi
>
> Gentle ping.
>
> Thanks,
> Qi
>
>>
>> Changelog in v1 -> v2:
>> - temporarily discard [PATCH v1 2/2] to allow this patch to be
>> merged first
>> - rebase onto the v5.19
>> - collect Reviewed-by and Acked-by
>>
>> Changelog in RFC -> v1:
>> - fix conflicts with commit f2c5092190f2 ("arch/*: Disable softirq
>> stacks on PREEMPT_RT.")
>>
>> arch/arm64/Kconfig | 1 +
>> arch/arm64/kernel/irq.c | 13 +++++++++++++
>> 2 files changed, 14 insertions(+)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index 571cc234d0b3..ee92f5887cf6 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -230,6 +230,7 @@ config ARM64
>> select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
>> select TRACE_IRQFLAGS_SUPPORT
>> select TRACE_IRQFLAGS_NMI_SUPPORT
>> + select HAVE_SOFTIRQ_ON_OWN_STACK
>> help
>> ARM 64-bit (AArch64) Linux support.
>> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
>> index bda49430c9ea..c36ad20a52f3 100644
>> --- a/arch/arm64/kernel/irq.c
>> +++ b/arch/arm64/kernel/irq.c
>> @@ -22,6 +22,7 @@
>> #include <linux/vmalloc.h>
>> #include <asm/daifflags.h>
>> #include <asm/vmap_stack.h>
>> +#include <asm/exception.h>
>> /* Only access this in an NMI enter/exit */
>> DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
>> @@ -71,6 +72,18 @@ static void init_irq_stacks(void)
>> }
>> #endif
>> +#ifndef CONFIG_PREEMPT_RT
>> +static void ____do_softirq(struct pt_regs *regs)
>> +{
>> + __do_softirq();
>> +}
>> +
>> +void do_softirq_own_stack(void)
>> +{
>> + call_on_irq_stack(NULL, ____do_softirq);
>> +}
>> +#endif
>> +
>> static void default_handle_irq(struct pt_regs *regs)
>> {
>> panic("IRQ taken without a root IRQ handler\n");
>
--
Thanks,
Qi
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack
2022-09-07 7:04 ` Qi Zheng
@ 2022-09-07 13:34 ` Will Deacon
2022-09-07 14:50 ` Qi Zheng
0 siblings, 1 reply; 6+ messages in thread
From: Will Deacon @ 2022-09-07 13:34 UTC (permalink / raw)
To: Qi Zheng
Cc: linux-arm-kernel, linux-kernel, Arnd Bergmann, Catalin Marinas,
Mark Rutland
On Wed, Sep 07, 2022 at 03:04:48PM +0800, Qi Zheng wrote:
>
>
> On 2022/8/26 12:16, Qi Zheng wrote:
> >
> >
> > On 2022/8/15 20:47, Qi Zheng wrote:
> > > Currently arm64 supports per-CPU IRQ stack, but softirqs
> > > are still handled in the task context.
> > >
> > > Since any call to local_bh_enable() at any level in the task's
> > > call stack may trigger a softirq processing run, which could
> > > potentially cause a task stack overflow if the combined stack
> > > footprints exceed the stack's size, let's run these softirqs
> > > on the IRQ stack as well.
> > >
> > > Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> > > Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> > > Acked-by: Will Deacon <will@kernel.org>
> > > ---
> > > v2: https://lore.kernel.org/lkml/20220802065325.39740-1-zhengqi.arch@bytedance.com/
> > > v1: https://lore.kernel.org/lkml/20220708094950.41944-1-zhengqi.arch@bytedance.com/
> > > RFC: https://lore.kernel.org/lkml/20220707110511.52129-1-zhengqi.arch@bytedance.com/
> > >
> > > Changelog in v2 -> v3:
> > > - rebase onto the v6.0-rc1
>
> Hi Will,
>
> Are we good to merge this patch? Or if there is anything else I need to
> do, please let me know. :)
I'm expecting Catalin to pick this one up for 6.1.
Will
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack
2022-09-07 13:34 ` Will Deacon
@ 2022-09-07 14:50 ` Qi Zheng
0 siblings, 0 replies; 6+ messages in thread
From: Qi Zheng @ 2022-09-07 14:50 UTC (permalink / raw)
To: Will Deacon, Catalin Marinas
Cc: linux-arm-kernel, linux-kernel, Arnd Bergmann, Mark Rutland
On 2022/9/7 21:34, Will Deacon wrote:
> On Wed, Sep 07, 2022 at 03:04:48PM +0800, Qi Zheng wrote:
>>
>>
>> On 2022/8/26 12:16, Qi Zheng wrote:
>>>
>>>
>>> On 2022/8/15 20:47, Qi Zheng wrote:
>>>> Currently arm64 supports per-CPU IRQ stack, but softirqs
>>>> are still handled in the task context.
>>>>
>>>> Since any call to local_bh_enable() at any level in the task's
>>>> call stack may trigger a softirq processing run, which could
>>>> potentially cause a task stack overflow if the combined stack
>>>> footprints exceed the stack's size, let's run these softirqs
>>>> on the IRQ stack as well.
>>>>
>>>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>>>> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
>>>> Acked-by: Will Deacon <will@kernel.org>
>>>> ---
>>>> v2: https://lore.kernel.org/lkml/20220802065325.39740-1-zhengqi.arch@bytedance.com/
>>>> v1: https://lore.kernel.org/lkml/20220708094950.41944-1-zhengqi.arch@bytedance.com/
>>>> RFC: https://lore.kernel.org/lkml/20220707110511.52129-1-zhengqi.arch@bytedance.com/
>>>>
>>>> Changelog in v2 -> v3:
>>>> - rebase onto the v6.0-rc1
>>
>> Hi Will,
>>
>> Are we good to merge this patch? Or if there is anything else I need to
>> do, please let me know. :)
>
> I'm expecting Catalin to pick this one up for 6.1.
Oh, I see. Looking forward to this.
Thanks a lot.
Qi
>
> Will
--
Thanks,
Qi
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack
2022-08-15 12:47 [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack Qi Zheng
2022-08-26 4:16 ` Qi Zheng
@ 2022-09-08 18:34 ` Catalin Marinas
1 sibling, 0 replies; 6+ messages in thread
From: Catalin Marinas @ 2022-09-08 18:34 UTC (permalink / raw)
To: Qi Zheng, will, mark.rutland, arnd; +Cc: linux-arm-kernel, linux-kernel
On Mon, 15 Aug 2022 20:47:39 +0800, Qi Zheng wrote:
> Currently arm64 supports per-CPU IRQ stack, but softirqs
> are still handled in the task context.
>
> Since any call to local_bh_enable() at any level in the task's
> call stack may trigger a softirq processing run, which could
> potentially cause a task stack overflow if the combined stack
> footprints exceed the stack's size, let's run these softirqs
> on the IRQ stack as well.
>
> [...]
Applied to arm64 (for-next/misc), thanks!
[1/1] arm64: run softirqs on the per-CPU IRQ stack
https://git.kernel.org/arm64/c/2d2f3bb897a3
--
Catalin
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2022-08-15 12:47 [PATCH v3] arm64: run softirqs on the per-CPU IRQ stack Qi Zheng
2022-08-26 4:16 ` Qi Zheng
2022-09-07 7:04 ` Qi Zheng
2022-09-07 13:34 ` Will Deacon
2022-09-07 14:50 ` Qi Zheng
2022-09-08 18:34 ` Catalin Marinas
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