This is a note to let you know that I've just added the patch titled
x86/ioapic: Handle allocation failures gracefully
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-ioapic-handle-allocation-failures-gracefully.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 65b658031eb9d065bdebda263e53d40aa62c5027
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Fri Aug 2 18:15:34 2024 +0200
x86/ioapic: Handle allocation failures gracefully
[ Upstream commit 830802a0fea8fb39d3dc9fb7d6b5581e1343eb1f ]
Breno observed panics when using failslab under certain conditions during
runtime:
can not alloc irq_pin_list (-1,0,20)
Kernel panic - not syncing: IO-APIC: failed to add irq-pin. Can not proceed
panic+0x4e9/0x590
mp_irqdomain_alloc+0x9ab/0xa80
irq_domain_alloc_irqs_locked+0x25d/0x8d0
__irq_domain_alloc_irqs+0x80/0x110
mp_map_pin_to_irq+0x645/0x890
acpi_register_gsi_ioapic+0xe6/0x150
hpet_open+0x313/0x480
That's a pointless panic which is a leftover of the historic IO/APIC code
which panic'ed during early boot when the interrupt allocation failed.
The only place which might justify panic is the PIT/HPET timer_check() code
which tries to figure out whether the timer interrupt is delivered through
the IO/APIC. But that code does not require to handle interrupt allocation
failures. If the interrupt cannot be allocated then timer delivery fails
and it either panics due to that or falls back to legacy mode.
Cure this by removing the panic wrapper around __add_pin_to_irq_node() and
making mp_irqdomain_alloc() aware of the failure condition and handle it as
any other failure in this function gracefully.
Reported-by: Breno Leitao <leitao@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Breno Leitao <leitao@xxxxxxxxxx>
Tested-by: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx>
Link: https://lore.kernel.org/all/ZqfJmUF8sXIyuSHN@xxxxxxxxx
Link: https://lore.kernel.org/all/20240802155440.275200843@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 00da6cf6b07dc..d0c5325d17510 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -352,27 +352,26 @@ static void ioapic_mask_entry(int apic, int pin)
* shared ISA-space IRQs, so we have to support them. We are super
* fast in the common case, and fast for shared ISA-space IRQs.
*/
-static int __add_pin_to_irq_node(struct mp_chip_data *data,
- int node, int apic, int pin)
+static bool add_pin_to_irq_node(struct mp_chip_data *data, int node, int apic, int pin)
{
struct irq_pin_list *entry;
- /* don't allow duplicates */
- for_each_irq_pin(entry, data->irq_2_pin)
+ /* Don't allow duplicates */
+ for_each_irq_pin(entry, data->irq_2_pin) {
if (entry->apic == apic && entry->pin == pin)
- return 0;
+ return true;
+ }
entry = kzalloc_node(sizeof(struct irq_pin_list), GFP_ATOMIC, node);
if (!entry) {
- pr_err("can not alloc irq_pin_list (%d,%d,%d)\n",
- node, apic, pin);
- return -ENOMEM;
+ pr_err("Cannot allocate irq_pin_list (%d,%d,%d)\n", node, apic, pin);
+ return false;
}
+
entry->apic = apic;
entry->pin = pin;
list_add_tail(&entry->list, &data->irq_2_pin);
-
- return 0;
+ return true;
}
static void __remove_pin_from_irq(struct mp_chip_data *data, int apic, int pin)
@@ -387,13 +386,6 @@ static void __remove_pin_from_irq(struct mp_chip_data *data, int apic, int pin)
}
}
-static void add_pin_to_irq_node(struct mp_chip_data *data,
- int node, int apic, int pin)
-{
- if (__add_pin_to_irq_node(data, node, apic, pin))
- panic("IO-APIC: failed to add irq-pin. Can not proceed\n");
-}
-
/*
* Reroute an IRQ to a different pin.
*/
@@ -1002,8 +994,7 @@ static int alloc_isa_irq_from_domain(struct irq_domain *domain,
if (irq_data && irq_data->parent_data) {
if (!mp_check_pin_attr(irq, info))
return -EBUSY;
- if (__add_pin_to_irq_node(irq_data->chip_data, node, ioapic,
- info->ioapic.pin))
+ if (!add_pin_to_irq_node(irq_data->chip_data, node, ioapic, info->ioapic.pin))
return -ENOMEM;
} else {
info->flags |= X86_IRQ_ALLOC_LEGACY;
@@ -3037,10 +3028,8 @@ int mp_irqdomain_alloc(struct irq_domain *domain, unsigned int virq,
return -ENOMEM;
ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, info);
- if (ret < 0) {
- kfree(data);
- return ret;
- }
+ if (ret < 0)
+ goto free_data;
INIT_LIST_HEAD(&data->irq_2_pin);
irq_data->hwirq = info->ioapic.pin;
@@ -3049,7 +3038,10 @@ int mp_irqdomain_alloc(struct irq_domain *domain, unsigned int virq,
irq_data->chip_data = data;
mp_irqdomain_get_attr(mp_pin_to_gsi(ioapic, pin), data, info);
- add_pin_to_irq_node(data, ioapic_alloc_attr_node(info), ioapic, pin);
+ if (!add_pin_to_irq_node(data, ioapic_alloc_attr_node(info), ioapic, pin)) {
+ ret = -ENOMEM;
+ goto free_irqs;
+ }
mp_preconfigure_entry(data);
mp_register_handler(virq, data->is_level);
@@ -3064,6 +3056,12 @@ int mp_irqdomain_alloc(struct irq_domain *domain, unsigned int virq,
ioapic, mpc_ioapic_id(ioapic), pin, virq,
data->is_level, data->active_low);
return 0;
+
+free_irqs:
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+free_data:
+ kfree(data);
+ return ret;
}
void mp_irqdomain_free(struct irq_domain *domain, unsigned int virq,
