LKML Archive on
 help / color / Atom feed
From: Thomas Gleixner <>
To: LKML <>
Cc:, Sebastian Siewior <>,
	Andy Shevchenko <>
Subject: [patch 1/2] x86/ioapic: Prevent inconsistent state when moving an interrupt
Date: Thu, 17 Oct 2019 12:19:01 +0200
Message-ID: <> (raw)
In-Reply-To: <>

There is an issue with threaded interrupts which are marked ONESHOT
and using the fasteoi handler.

  if (IS_ONESHOT())
      if (setaffinity_pending) {

So if setaffinity is pending the interrupt will be moved and then
unconditionally unmasked at the ioapic level, which is wrong in two

 1) It should be kept masked up to the point where the threaded handler

 2) The physical chip state and the software masked state are inconsistent

Guard both the mask and the unmask with a check for the software masked
state. If the line is marked masked then the ioapic line is also masked, so
both mask_ioapic() and unmask_ioapic() can be skipped safely.

Fixes: 3aa551c9b4c4 ("genirq: add threaded interrupt handler support")
Signed-off-by: Thomas Gleixner <>
 arch/x86/kernel/apic/io_apic.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1729,7 +1729,8 @@ static inline bool ioapic_irqd_mask(stru
 	/* If we are moving the irq we need to mask it */
 	if (unlikely(irqd_is_setaffinity_pending(data))) {
-		mask_ioapic_irq(data);
+		if (!irqd_irq_masked(data))
+			mask_ioapic_irq(data);
 		return true;
 	return false;
@@ -1766,7 +1767,9 @@ static inline void ioapic_irqd_unmask(st
 		if (!io_apic_level_ack_pending(data->chip_data))
-		unmask_ioapic_irq(data);
+		/* If the irq is masked in the core, leave it */
+		if (!irqd_irq_masked(data))
+			unmask_ioapic_irq(data);

  reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-17 10:19 [patch 0/2] x86/ioapic: Prevent inconsistent state Thomas Gleixner
2019-10-17 10:19 ` Thomas Gleixner [this message]
2019-10-24 10:13   ` [tip: x86/apic] x86/ioapic: Prevent inconsistent state when moving an interrupt tip-bot2 for Thomas Gleixner
2019-10-17 10:19 ` [patch 2/2] x86/ioapic: Rename misnamed functions Thomas Gleixner
2019-10-24 10:13   ` [tip: x86/apic] " tip-bot2 for Thomas Gleixner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on

Archives are clonable:
	git clone --mirror lkml/git/0.git
	git clone --mirror lkml/git/1.git
	git clone --mirror lkml/git/2.git
	git clone --mirror lkml/git/3.git
	git clone --mirror lkml/git/4.git
	git clone --mirror lkml/git/5.git
	git clone --mirror lkml/git/6.git
	git clone --mirror lkml/git/7.git
	git clone --mirror lkml/git/8.git
	git clone --mirror lkml/git/9.git
	git clone --mirror lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ \
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone