]> www.infradead.org Git - users/jedix/linux-maple.git/commit
genirq/cpuhotplug: Restore affinity even for suspended IRQ
authorBrian Norris <briannorris@chromium.org>
Thu, 12 Jun 2025 18:32:52 +0000 (11:32 -0700)
committerThomas Gleixner <tglx@linutronix.de>
Fri, 13 Jun 2025 13:13:35 +0000 (15:13 +0200)
commit72218d74c9c57b8ea36c2a58875dff406fc10462
tree982e97296adcd1d83f85a535ade024dd2df965ec
parent2b32fc8ff08deac3aa509f321a28e21b1eea5525
genirq/cpuhotplug: Restore affinity even for suspended IRQ

Commit 788019eb559f ("genirq: Retain disable depth for managed interrupts
across CPU hotplug") tried to make managed shutdown/startup properly
reference counted, but it missed the fact that the unplug and hotplug code
has an intentional imbalance by skipping IRQS_SUSPENDED interrupts on
the "restore" path.

This means that if a managed-affinity interrupt was both suspended and
managed-shutdown (such as may happen during system suspend / S3), resume
skips calling irq_startup_managed(), and would again have an unbalanced
depth this time, with a positive value (i.e., remaining unexpectedly
masked).

This IRQS_SUSPENDED check was introduced in commit a60dd06af674
("genirq/cpuhotplug: Skip suspended interrupts when restoring affinity")
for essentially the same reason as commit 788019eb559f, to prevent that
irq_startup() would unconditionally re-enable an interrupt too early.

Because irq_startup_managed() now respsects the disable-depth count, the
IRQS_SUSPENDED check is not longer needed, and instead, it causes harm.

Thus, drop the IRQS_SUSPENDED check, and restore balance.

This effectively reverts commit a60dd06af674 ("genirq/cpuhotplug: Skip
suspended interrupts when restoring affinity"), because it is replaced
by commit 788019eb559f ("genirq: Retain disable depth for managed
interrupts across CPU hotplug").

Fixes: 788019eb559f ("genirq: Retain disable depth for managed interrupts across CPU hotplug")
Reported-by: Aleksandrs Vinarskis <alex.vinarskis@gmail.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Aleksandrs Vinarskis <alex.vinarskis@gmail.com>
Link: https://lore.kernel.org/all/20250612183303.3433234-3-briannorris@chromium.org
Closes: https://lore.kernel.org/lkml/24ec4adc-7c80-49e9-93ee-19908a97ab84@gmail.com/
kernel/irq/cpuhotplug.c