genirq: Take the proposed affinity at face value if force==true
authorLuiz Capitulino <luizcap@amazon.com>
Mon, 28 Nov 2022 17:08:35 +0000 (17:08 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 2 Dec 2022 16:41:12 +0000 (17:41 +0100)
commit7d0c25b5fe54ebd410832257c95a62ed3cf29e0e
treefa07eaae3a3aabd2f437fcfc680508eb2a064112
parentf17657cce069f7566d26b07db199f372287c69b4
genirq: Take the proposed affinity at face value if force==true

From: Marc Zyngier <maz@kernel.org>

commit c48c8b829d2b966a6649827426bcdba082ccf922 upstream.

Although setting the affinity of an interrupt to a set of CPUs that doesn't
have any online CPU is generally frowned apon, there are a few limited
cases where such affinity is set from a CPUHP notifier, setting the
affinity to a CPU that isn't online yet.

The saving grace is that this is always done using the 'force' attribute,
which gives a hint that the affinity setting can be outside of the online
CPU mask and the callsite set this flag with the knowledge that the
underlying interrupt controller knows to handle it.

This restores the expected behaviour on Marek's system.

Fixes: 33de0aa4bae9 ("genirq: Always limit the affinity to online CPUs")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/4b7fc13c-887b-a664-26e8-45aed13f048a@samsung.com
Link: https://lore.kernel.org/r/20220414140011.541725-1-maz@kernel.org
Signed-off-by: Luiz Capitulino <luizcap@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/irq/manage.c