[tip: irq/core] genirq: Add might_sleep() to disable_irq()

[tip-bot2 for Manfred Spraul]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     17549b0f184d870f2cfa4e5cfa79f4c4905ed757
Gitweb:        https://git.kernel.org/tip/17549b0f184d870f2cfa4e5cfa79f4c4905ed757
Author:        Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
AuthorDate:    Fri, 16 Dec 2022 16:04:41 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Wed, 11 Jan 2023 19:35:13 +01:00

genirq: Add might_sleep() to disable_irq()

With the introduction of threaded interrupt handlers, it is virtually
never safe to call disable_irq() from non-premptible context.

Thus: Update the documentation, add an explicit might_sleep() to catch any
offenders. This is more obvious and straight forward than the implicit
might_sleep() check deeper down in the disable_irq() call chain.

Fixes: 3aa551c9b4c4 ("genirq: add threaded interrupt handler support")
Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221216150441.200533-3-manfred@xxxxxxxxxxxxxxxx


---
 kernel/irq/manage.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 5b7cf28..8ce7549 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -723,10 +723,13 @@ EXPORT_SYMBOL(disable_irq_nosync);
  *	to complete before returning. If you use this function while
  *	holding a resource the IRQ handler may need you will deadlock.
  *
- *	This function may be called - with care - from IRQ context.
+ *	Can only be called from preemptible code as it might sleep when
+ *	an interrupt thread is associated to @irq.
+ *
  */
 void disable_irq(unsigned int irq)
 {
+	might_sleep();
 	if (!__disable_irq_nosync(irq))
 		synchronize_irq(irq);
 }