linux-stable.git/kernel/irq, branch linux-4.19.y

genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline

2024-06-16T11:23:38+00:00

commit a6c11c0a5235fb144a65e0cb2ffd360ddc1f6c32 upstream.

The absence of IRQD_MOVE_PCNTXT prevents immediate effectiveness of
interrupt affinity reconfiguration via procfs. Instead, the change is
deferred until the next instance of the interrupt being triggered on the
original CPU.

When the interrupt next triggers on the original CPU, the new affinity is
enforced within __irq_move_irq(). A vector is allocated from the new CPU,
but the old vector on the original CPU remains and is not immediately
reclaimed. Instead, apicd->move_in_progress is flagged, and the reclaiming
process is delayed until the next trigger of the interrupt on the new CPU.

Upon the subsequent triggering of the interrupt on the new CPU,
irq_complete_move() adds a task to the old CPU's vector_cleanup list if it
remains online. Subsequently, the timer on the old CPU iterates over its
vector_cleanup list, reclaiming old vectors.

However, a rare scenario arises if the old CPU is outgoing before the
interrupt triggers again on the new CPU.

In that case irq_force_complete_move() is not invoked on the outgoing CPU
to reclaim the old apicd->prev_vector because the interrupt isn't currently
affine to the outgoing CPU, and irq_needs_fixup() returns false. Even
though __vector_schedule_cleanup() is later called on the new CPU, it
doesn't reclaim apicd->prev_vector; instead, it simply resets both
apicd->move_in_progress and apicd->prev_vector to 0.

As a result, the vector remains unreclaimed in vector_matrix, leading to a
CPU vector leak.

To address this issue, move the invocation of irq_force_complete_move()
before the irq_needs_fixup() call to reclaim apicd->prev_vector, if the
interrupt is currently or used to be affine to the outgoing CPU.

Additionally, reclaim the vector in __vector_schedule_cleanup() as well,
following a warning message, although theoretically it should never see
apicd->move_in_progress with apicd->prev_cpu pointing to an offline CPU.

Fixes: f0383c24b485 ("genirq/cpuhotplug: Add support for cleaning up move in progress")
Signed-off-by: Dongli Zhang 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240522220218.162423-1-dongli.zhang@oracle.com
Signed-off-by: Greg Kroah-Hartman

genirq/generic_chip: Make irq_remove_generic_chip() irqdomain aware

2023-11-28T16:46:34+00:00

commit 5e7afb2eb7b2a7c81e9f608cbdf74a07606fd1b5 upstream.

irq_remove_generic_chip() calculates the Linux interrupt number for removing the
handler and interrupt chip based on gc::irq_base as a linear function of
the bit positions of set bits in the @msk argument.

When the generic chip is present in an irq domain, i.e. created with a call
to irq_alloc_domain_generic_chips(), gc::irq_base contains not the base
Linux interrupt number.  It contains the base hardware interrupt for this
chip. It is set to 0 for the first chip in the domain, 0 + N for the next
chip, where $N is the number of hardware interrupts per chip.

That means the Linux interrupt number cannot be calculated based on
gc::irq_base for irqdomain based chips without a domain map lookup, which
is currently missing.

Rework the code to take the irqdomain case into account and calculate the
Linux interrupt number by a irqdomain lookup of the domain specific
hardware interrupt number.

[ tglx: Massage changelog. Reshuffle the logic and add a proper comment. ]

Fixes: cfefd21e693d ("genirq: Add chip suspend and resume callbacks")
Signed-off-by: Herve Codina 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231024150335.322282-1-herve.codina@bootlin.com
Signed-off-by: Greg Kroah-Hartman

genirq/matrix: Exclude managed interrupts in irq_matrix_allocated()

2023-11-20T09:29:16+00:00

[ Upstream commit a0b0bad10587ae2948a7c36ca4ffc206007fbcf3 ]

When a CPU is about to be offlined, x86 validates that all active
interrupts which are targeted to this CPU can be migrated to the remaining
online CPUs. If not, the offline operation is aborted.

The validation uses irq_matrix_allocated() to retrieve the number of
vectors which are allocated on the outgoing CPU. The returned number of
allocated vectors includes also vectors which are associated to managed
interrupts.

That's overaccounting because managed interrupts are:

  - not migrated when the affinity mask of the interrupt targets only
    the outgoing CPU

  - migrated to another CPU, but in that case the vector is already
    pre-allocated on the potential target CPUs and must not be taken into
    account.

As a consequence the check whether the remaining online CPUs have enough
capacity for migrating the allocated vectors from the outgoing CPU might
fail incorrectly.

Let irq_matrix_allocated() return only the number of allocated non-managed
interrupts to make this validation check correct.

[ tglx: Amend changelog and fixup kernel-doc comment ]

Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator")
Reported-by: Wendy Wang 
Signed-off-by: Chen Yu 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20231020072522.557846-1-yu.c.chen@intel.com
Signed-off-by: Sasha Levin

irqdomain: Drop bogus fwspec-mapping error handling

2023-03-11T15:31:52+00:00

commit e3b7ab025e931accdc2c12acf9b75c6197f1c062 upstream.

In case a newly allocated IRQ ever ends up not having any associated
struct irq_data it would not even be possible to dispose the mapping.

Replace the bogus disposal with a WARN_ON().

This will also be used to fix a shared-interrupt mapping race, hence the
CC-stable tag.

Fixes: 1e2a7d78499e ("irqdomain: Don't set type when mapping an IRQ")
Cc: stable@vger.kernel.org      # 4.8
Tested-by: Hsin-Yi Wang 
Tested-by: Mark-PK Tsai 
Signed-off-by: Johan Hovold 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20230213104302.17307-4-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman

irqdomain: Fix disassociation race

2023-03-11T15:31:52+00:00

commit 3f883c38f5628f46b30bccf090faec054088e262 upstream.

The global irq_domain_mutex is held when mapping interrupts from
non-hierarchical domains but currently not when disposing them.

This specifically means that updates of the domain mapcount is racy
(currently only used for statistics in debugfs).

Make sure to hold the global irq_domain_mutex also when disposing
mappings from non-hierarchical domains.

Fixes: 9dc6be3d4193 ("genirq/irqdomain: Add map counter")
Cc: stable@vger.kernel.org      # 4.13
Tested-by: Hsin-Yi Wang 
Tested-by: Mark-PK Tsai 
Signed-off-by: Johan Hovold 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20230213104302.17307-3-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman

irqdomain: Fix association race

2023-03-11T15:31:51+00:00

commit b06730a571a9ff1ba5bd6b20bf9e50e5a12f1ec6 upstream.

The sanity check for an already mapped virq is done outside of the
irq_domain_mutex-protected section which means that an (unlikely) racing
association may not be detected.

Fix this by factoring out the association implementation, which will
also be used in a follow-on change to fix a shared-interrupt mapping
race.

Fixes: ddaf144c61da ("irqdomain: Refactor irq_domain_associate_many()")
Cc: stable@vger.kernel.org      # 3.11
Tested-by: Hsin-Yi Wang 
Tested-by: Mark-PK Tsai 
Signed-off-by: Johan Hovold 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20230213104302.17307-2-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman

random: remove unused irq_flags argument from add_interrupt_randomness()

2022-06-25T09:49:01+00:00

commit 703f7066f40599c290babdb79dd61319264987e9 upstream.

Since commit
   ee3e00e9e7101 ("random: use registers from interrupted code for CPU's w/o a cycle counter")

the irq_flags argument is no longer used.

Remove unused irq_flags.

Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: Dexuan Cui 
Cc: H. Peter Anvin 
Cc: Haiyang Zhang 
Cc: Ingo Molnar 
Cc: K. Y. Srinivasan 
Cc: Stephen Hemminger 
Cc: Thomas Gleixner 
Cc: Wei Liu 
Cc: linux-hyperv@vger.kernel.org
Cc: x86@kernel.org
Signed-off-by: Sebastian Andrzej Siewior 
Acked-by: Wei Liu 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

genirq: Synchronize interrupt thread startup

2022-05-12T10:20:24+00:00

commit 8707898e22fd665bc1d7b18b809be4b56ce25bdd upstream.

A kernel hang can be observed when running setserial in a loop on a kernel
with force threaded interrupts. The sequence of events is:

   setserial
     open("/dev/ttyXXX")
       request_irq()
     do_stuff()
      -> serial interrupt
         -> wake(irq_thread)
	      desc->threads_active++;
     close()
       free_irq()
         kthread_stop(irq_thread)
     synchronize_irq() <- hangs because desc->threads_active != 0

The thread is created in request_irq() and woken up, but does not get on a
CPU to reach the actual thread function, which would handle the pending
wake-up. kthread_stop() sets the should stop condition which makes the
thread immediately exit, which in turn leaves the stale threads_active
count around.

This problem was introduced with commit 519cc8652b3a, which addressed a
interrupt sharing issue in the PCIe code.

Before that commit free_irq() invoked synchronize_irq(), which waits for
the hard interrupt handler and also for associated threads to complete.

To address the PCIe issue synchronize_irq() was replaced with
__synchronize_hardirq(), which only waits for the hard interrupt handler to
complete, but not for threaded handlers.

This was done under the assumption, that the interrupt thread already
reached the thread function and waits for a wake-up, which is guaranteed to
be handled before acting on the stop condition. The problematic case, that
the thread would not reach the thread function, was obviously overlooked.

Make sure that the interrupt thread is really started and reaches
thread_fn() before returning from __setup_irq().

This utilizes the existing wait queue in the interrupt descriptor. The
wait queue is unused for non-shared interrupts. For shared interrupts the
usage might cause a spurious wake-up of a waiter in synchronize_irq() or the
completion of a threaded handler might cause a spurious wake-up of the
waiter for the ready flag. Both are harmless and have no functional impact.

[ tglx: Amended changelog ]

Fixes: 519cc8652b3a ("genirq: Synchronize only with single thread on free_irq()")
Signed-off-by: Thomas Pfaff 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Marc Zyngier 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/552fe7b4-9224-b183-bb87-a8f36d335690@pcs.com
Signed-off-by: Greg Kroah-Hartman

genirq/msi: Ensure deactivation on teardown

2021-08-26T12:36:40+00:00

commit dbbc93576e03fbe24b365fab0e901eb442237a8a upstream.

msi_domain_alloc_irqs() invokes irq_domain_activate_irq(), but
msi_domain_free_irqs() does not enforce deactivation before tearing down
the interrupts.

This happens when PCI/MSI interrupts are set up and never used before being
torn down again, e.g. in error handling pathes. The only place which cleans
that up is the error handling path in msi_domain_alloc_irqs().

Move the cleanup from msi_domain_alloc_irqs() into msi_domain_free_irqs()
to cure that.

Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early")
Signed-off-by: Bixuan Cui 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210518033117.78104-1-cuibixuan@huawei.com
Signed-off-by: Greg Kroah-Hartman

genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP

2021-08-26T12:36:40+00:00

commit 826da771291fc25a428e871f9e7fb465e390f852 upstream.

X86 IO/APIC and MSI interrupts (when used without interrupts remapping)
require that the affinity setup on startup is done before the interrupt is
enabled for the first time as the non-remapped operation mode cannot safely
migrate enabled interrupts from arbitrary contexts. Provide a new irq chip
flag which allows affected hardware to request this.

This has to be opt-in because there have been reports in the past that some
interrupt chips cannot handle affinity setting before startup.

Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner 
Tested-by: Marc Zyngier 
Reviewed-by: Marc Zyngier 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.779791738@linutronix.de
Signed-off-by: Greg Kroah-Hartman