A single fix for a recent (introduced in 5.16) regression in the core
interrupt code. The consolidation of the interrupt handler invocation code
added an unconditional warning when generic_handle_domain_irq() is invoked
from outside hard interrupt context. That's overbroad as the requirement
for invoking these handlers in hard interrupt context is only required for
certain interrupt types. The subsequently called code already contains a
warning which triggers conditionally for interrupt chips which indicate
this requirement in their properties. Remove the overbroad one.
genirq: Remove WARN_ON_ONCE() in generic_handle_domain_irq()
Since commit 0953fb263714 ("irq: remove handle_domain_{irq,nmi}()"),
generic_handle_domain_irq() warns if called outside hardirq context, even
though the function calls down to handle_irq_desc(), which warns about the
same, but conditionally on handle_enforce_irqctx().
The newly added warning is a false positive if the interrupt originates
from any other irqchip than x86 APIC or ARM GIC/GICv3. Those are the only
ones for which handle_enforce_irqctx() returns true. Per commit
c16816acd086 ("genirq: Add protection against unsafe usage of
generic_handle_irq()"):
"In general calling generic_handle_irq() with interrupts disabled from non
interrupt context is harmless. For some interrupt controllers like the
x86 trainwrecks this is outright dangerous as it might corrupt state if
an interrupt affinity change is pending."
Examples for interrupt chips where the warning is a false positive are
USB-attached GPIO controllers such as drivers/gpio/gpio-dln2.c:
USB gadgets are incapable of directly signaling an interrupt because they
cannot initiate a bus transaction by themselves. All communication on
the bus is initiated by the host controller, which polls a gadget's
Interrupt Endpoint in regular intervals. If an interrupt is pending,
that information is passed up the stack in softirq context, from which a
hardirq is synthesized via generic_handle_domain_irq().
Remove the warning to eliminate such false positives.
Fixes: 0953fb263714 ("irq: remove handle_domain_{irq,nmi}()")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Jakub Kicinski <kuba@kernel.org>
CC: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Octavian Purdila <octavian.purdila@nxp.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220505113207.487861b2@kernel.org
Link: https://lore.kernel.org/r/20220506203242.GA1855@wunner.de
Link: https://lore.kernel.org/r/c3caf60bfa78e5fdbdf483096b7174da65d1813a.1652168866.git.lukas@wunner.de
1 file changed
