This is a note to let you know that I've just added the patch titled

genirq/matrix: Handle CPU offlining proper

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: genirq-matrix-handle-cpu-offlining-proper.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 651ca2c00405a2ae3870cc0b4f15a182eb6fbe26 Mon Sep 17 00:00:00 2001

From: Thomas Gleixner tglx@linutronix.de Date: Thu, 22 Feb 2018 12:08:05 +0100 Subject: genirq/matrix: Handle CPU offlining proper

From: Thomas Gleixner tglx@linutronix.de

commit 651ca2c00405a2ae3870cc0b4f15a182eb6fbe26 upstream.

At CPU hotunplug the corresponding per cpu matrix allocator is shut down and the allocated interrupt bits are discarded under the assumption that all allocated bits have been either migrated away or shut down through the managed interrupts mechanism.

This is not true because interrupts which are not started up might have a vector allocated on the outgoing CPU. When the interrupt is started up later or completely shutdown and freed then the allocated vector is handed back, triggering warnings or causing accounting issues which result in suspend failures and other issues.

Change the CPU hotplug mechanism of the matrix allocator so that the remaining allocations at unplug time are preserved and global accounting at hotplug is correctly readjusted to take the dormant vectors into account.

Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator") Reported-by: Yuriy Vostrikov delamonpansie@gmail.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: Yuriy Vostrikov delamonpansie@gmail.com Cc: Peter Zijlstra peterz@infradead.org Cc: Randy Dunlap rdunlap@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180222112316.849980972@linutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- kernel/irq/matrix.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-)

--- a/kernel/irq/matrix.c +++ b/kernel/irq/matrix.c @@ -16,6 +16,7 @@ struct cpumap { unsigned int available; unsigned int allocated; unsigned int managed; + bool initialized; bool online; unsigned long alloc_map[IRQ_MATRIX_SIZE]; unsigned long managed_map[IRQ_MATRIX_SIZE]; @@ -81,9 +82,11 @@ void irq_matrix_online(struct irq_matrix

BUG_ON(cm->online);

- bitmap_zero(cm->alloc_map, m->matrix_bits); - cm->available = m->alloc_size - (cm->managed + m->systembits_inalloc); - cm->allocated = 0; + if (!cm->initialized) { + cm->available = m->alloc_size; + cm->available -= cm->managed + m->systembits_inalloc; + cm->initialized = true; + } m->global_available += cm->available; cm->online = true; m->online_maps++; @@ -370,14 +373,16 @@ void irq_matrix_free(struct irq_matrix * if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end)) return;

- if (cm->online) { - clear_bit(bit, cm->alloc_map); - cm->allocated--; + clear_bit(bit, cm->alloc_map); + cm->allocated--; + + if (cm->online) m->total_allocated--; - if (!managed) { - cm->available++; + + if (!managed) { + cm->available++; + if (cm->online) m->global_available++; - } } trace_irq_matrix_free(bit, cpu, m, cm); }

Patches currently in stable-queue which might be from tglx@linutronix.de are

queue-4.15/x86-oprofile-fix-bogus-gcc-8-warning-in-nmi_setup.patch queue-4.15/x86-apic-vector-handle-vector-release-on-cpu-unplug-correctly.patch queue-4.15/genirq-matrix-handle-cpu-offlining-proper.patch queue-4.15/kbuild-always-define-endianess-in-kconfig.h.patch