4.15-stable review patch. If anyone has any objections, please let me know.
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From: Sam Bobroff sam.bobroff@au1.ibm.com
commit c9dccf1d074a67d36c510845f663980d69e3409b upstream.
Currently if the kernel receives a memory hot-unplug event early enough, it may get stuck in an infinite loop in dissolve_free_huge_pages(). This appears as a stall just after:
pseries-hotplug-mem: Attempting to hot-remove XX LMB(s) at YYYYYYYY
It appears to be caused by "minimum_order" being uninitialized, due to init_ras_IRQ() executing before hugetlb_init().
To correct this, extract the part of init_ras_IRQ() that enables hotplug event processing and place it in the machine_late_initcall phase, which is guaranteed to be after hugetlb_init() is called.
Signed-off-by: Sam Bobroff sam.bobroff@au1.ibm.com Acked-by: Balbir Singh bsingharora@gmail.com [mpe: Reorder the functions to make the diff readable] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/platforms/pseries/ras.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-)
--- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c @@ -49,6 +49,28 @@ static irqreturn_t ras_error_interrupt(i
/* + * Enable the hotplug interrupt late because processing them may touch other + * devices or systems (e.g. hugepages) that have not been initialized at the + * subsys stage. + */ +int __init init_ras_hotplug_IRQ(void) +{ + struct device_node *np; + + /* Hotplug Events */ + np = of_find_node_by_path("/event-sources/hot-plug-events"); + if (np != NULL) { + if (dlpar_workqueue_init() == 0) + request_event_sources_irqs(np, ras_hotplug_interrupt, + "RAS_HOTPLUG"); + of_node_put(np); + } + + return 0; +} +machine_late_initcall(pseries, init_ras_hotplug_IRQ); + +/* * Initialize handlers for the set of interrupts caused by hardware errors * and power system events. */ @@ -66,15 +88,6 @@ static int __init init_ras_IRQ(void) of_node_put(np); }
- /* Hotplug Events */ - np = of_find_node_by_path("/event-sources/hot-plug-events"); - if (np != NULL) { - if (dlpar_workqueue_init() == 0) - request_event_sources_irqs(np, ras_hotplug_interrupt, - "RAS_HOTPLUG"); - of_node_put(np); - } - /* EPOW Events */ np = of_find_node_by_path("/event-sources/epow-events"); if (np != NULL) {