Messages in this thread Patch in this message | | | From | Borislav Petkov <> | Subject | [PATCH] irqdomain: Correct early allocation of irq domains with IRQs off | Date | Sun, 30 Nov 2014 13:37:43 +0100 |
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From: Borislav Petkov <bp@suse.de>
I'm seeing the following lockdep splat on an x2APIC machine with interrupts remapping. The problem is that enable_IR_x2apic() disables interrupts before doing any further initialization. However, after having moved to irq domains, domain allocation cannot happen with interrupts disabled (GFP_KERNEL).
A proper fix would be to move that initialization to the early irq setup path, which is something for another day. It is more involved work too.
So do a temporary fix which should not encourage the behaviour of even assuming the irq domains code should be called with interrupts disabled. Make it x86-only too.
... dmar: Host address width 36 dmar: DRHD base: 0x000000fed90000 flags: 0x0 dmar: IOMMU 0: reg_base_addr fed90000 ver 1:0 cap c0000020e60262 ecap f0101a dmar: DRHD base: 0x000000fed91000 flags: 0x1 dmar: IOMMU 1: reg_base_addr fed91000 ver 1:0 cap c9008020660262 ecap f0105a dmar: RMRR base: 0x000000da2ba000 end: 0x000000da2d0fff dmar: RMRR base: 0x000000db800000 end: 0x000000df9fffff IOAPIC id 2 under DRHD base 0xfed91000 IOMMU 1 HPET id 0 under DRHD base 0xfed91000 Queued invalidation will be enabled to support x2apic and Intr-remapping. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2744 lockdep_trace_alloc+0xd4/0xe0() DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)) Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.18.0-rc6+ #1 Hardware name: LENOVO 2320CTO/2320CTO, BIOS G2ET86WW (2.06 ) 11/13/2012 0000000000000009 ffff880213d07b58 ffffffff816502d7 0000000000000000 ffff880213d07ba8 ffff880213d07b98 ffffffff81059790 0000000000000001 0000000000000092 0000000000000000 00000000000080d0 0000000000000000 Call Trace: dump_stack warn_slowpath_common warn_slowpath_fmt lockdep_trace_alloc __alloc_pages_nodemask ? get_page_from_freelist ? trace_hardirqs_off_caller alloc_kmem_pages_node kmalloc_large_node __kmalloc_node ? __dmar_enable_qi __irq_domain_add irq_domain_add_hierarchy intel_setup_irq_remapping.part.4 intel_enable_irq_remapping irq_remapping_enable enable_IR enable_IR_x2apic default_setup_apic_routing native_smp_prepare_cpus kernel_init_freeable ? ret_from_fork ? rest_init kernel_init ret_from_fork ? rest_init ---[ end trace fac50e785fc22942 ]--- Enabled IRQ remapping in x2apic mode Enabling x2apic Enabled x2apic Switched APIC routing to cluster x2apic. ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 ...
Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Yijing Wang <wangyijing@huawei.com> Cc: Yingjoe Chen <yingjoe.chen@mediatek.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Joerg Roedel <joro@8bytes.org> Link: Link: http://lkml.kernel.org/r/20141129125319.GA6491@pd.tnic Signed-off-by: Borislav Petkov <bp@suse.de> --- kernel/irq/irqdomain.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 7fac311057b8..3395d8923f96 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -46,14 +46,31 @@ struct irq_domain *__irq_domain_add(struct device_node *of_node, int size, void *host_data) { struct irq_domain *domain; + gfp_t gfp_flags = GFP_KERNEL; + +#ifdef CONFIG_X86 + /* + * BIG FAT COMMENT: Early initialization paths like enable_IR_x2apic(), + * for example, call into here with interrupts disabled but then we do + * allocate memory and can sleep so no-no. A proper fix would be to do + * x2APIC IR setup in the early irq setup path but it is too late for + * fixing it this way now, shortly before the merge window. + * + * So we do this little brown paper bag, which is temporary! Do not even + * think of calling irq domain setup code with IRQs disabled. You will + * get frozen-sharked! + */ + if (irqs_disabled()) + gfp_flags = GFP_NOFS; +#endif domain = kzalloc_node(sizeof(*domain) + (sizeof(unsigned int) * size), - GFP_KERNEL, of_node_to_nid(of_node)); + gfp_flags, of_node_to_nid(of_node)); if (WARN_ON(!domain)) return NULL; /* Fill structure */ - INIT_RADIX_TREE(&domain->revmap_tree, GFP_KERNEL); + INIT_RADIX_TREE(&domain->revmap_tree, gfp_flags); domain->ops = ops; domain->host_data = host_data; domain->of_node = of_node_get(of_node); -- 2.0.0
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