Linux-rt-users Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH v2] softirq: add irq off checking for __raise_softirq_irqoff
@ 2020-08-14  4:55 Jiafei Pan
  2020-09-10  2:30 ` Jiafei Pan
  0 siblings, 1 reply; 2+ messages in thread
From: Jiafei Pan @ 2020-08-14  4:55 UTC (permalink / raw)
  To: peterz, mingo, tglx, rostedt, romain.perier, will
  Cc: linux-kernel, linux-rt-users, jiafei.pan, leoyang.li,
	vladimir.oltean, Jiafei Pan

__raise_softirq_irqoff() will update per-CPU mask of pending softirqs,
it need to be called in irq disabled context in order to keep it atomic
operation, otherwise it will be interrupted by hardware interrupt,
and per-CPU softirqs pending mask will be corrupted, the result is
there will be unexpected issue, for example hrtimer soft irq will
be losed and soft hrtimer will never be expire and handled.

Enable CONFIG_PROVE_LOCKING to use lockdep_assert_irqs_disabled() to
check hardirqs and softirqs status, and provide warning in irqs enabled
context.

Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>
---
Changes in v2:
- use lockdep_assert_irqs_disabled()
- removed extra comments
- changed commit message

 kernel/softirq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index bf88d7f62433..09229ad82209 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -481,6 +481,7 @@ void raise_softirq(unsigned int nr)
 
 void __raise_softirq_irqoff(unsigned int nr)
 {
+	lockdep_assert_irqs_disabled();
 	trace_softirq_raise(nr);
 	or_softirq_pending(1UL << nr);
 }
-- 
2.17.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* RE: [PATCH v2] softirq: add irq off checking for __raise_softirq_irqoff
  2020-08-14  4:55 [PATCH v2] softirq: add irq off checking for __raise_softirq_irqoff Jiafei Pan
@ 2020-09-10  2:30 ` Jiafei Pan
  0 siblings, 0 replies; 2+ messages in thread
From: Jiafei Pan @ 2020-09-10  2:30 UTC (permalink / raw)
  To: Jiafei Pan, peterz, mingo, tglx, rostedt, romain.perier, will
  Cc: linux-kernel, linux-rt-users, Leo Li, Vladimir Oltean, Jiafei Pan

@Thomas Gleixner, any more comments for v2 patch? Can we merge it? Thanks.

Best Regards,
Jiafei.

> -----Original Message-----
> From: Jiafei Pan <Jiafei.Pan@nxp.com>
> Sent: Friday, August 14, 2020 12:55 PM
> To: peterz@infradead.org; mingo@kernel.org; tglx@linutronix.de;
> rostedt@goodmis.org; romain.perier@gmail.com; will@kernel.org
> Cc: linux-kernel@vger.kernel.org; linux-rt-users@vger.kernel.org; Jiafei Pan
> <jiafei.pan@nxp.com>; Leo Li <leoyang.li@nxp.com>; Vladimir Oltean
> <vladimir.oltean@nxp.com>; Jiafei Pan <jiafei.pan@nxp.com>
> Subject: [PATCH v2] softirq: add irq off checking for __raise_softirq_irqoff
> 
> __raise_softirq_irqoff() will update per-CPU mask of pending softirqs,
> it need to be called in irq disabled context in order to keep it atomic
> operation, otherwise it will be interrupted by hardware interrupt,
> and per-CPU softirqs pending mask will be corrupted, the result is
> there will be unexpected issue, for example hrtimer soft irq will
> be losed and soft hrtimer will never be expire and handled.
> 
> Enable CONFIG_PROVE_LOCKING to use lockdep_assert_irqs_disabled() to
> check hardirqs and softirqs status, and provide warning in irqs enabled
> context.
> 
> Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>
> ---
> Changes in v2:
> - use lockdep_assert_irqs_disabled()
> - removed extra comments
> - changed commit message
> 
>  kernel/softirq.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index bf88d7f62433..09229ad82209 100644
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -481,6 +481,7 @@ void raise_softirq(unsigned int nr)
> 
>  void __raise_softirq_irqoff(unsigned int nr)
>  {
> +	lockdep_assert_irqs_disabled();
>  	trace_softirq_raise(nr);
>  	or_softirq_pending(1UL << nr);
>  }
> --
> 2.17.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, back to index

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-14  4:55 [PATCH v2] softirq: add irq off checking for __raise_softirq_irqoff Jiafei Pan
2020-09-10  2:30 ` Jiafei Pan

Linux-rt-users Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rt-users/0 linux-rt-users/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rt-users linux-rt-users/ https://lore.kernel.org/linux-rt-users \
		linux-rt-users@vger.kernel.org
	public-inbox-index linux-rt-users

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rt-users


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git