From 9ae0522537852408f0f48af888e44d6876777463 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 6 Mar 2020 14:03:48 +0100 Subject: PCI/AER: Fix the broken interrupt injection The AER error injection mechanism just blindly abuses generic_handle_irq() which is really not meant for consumption by random drivers. The include of linux/irq.h should have been a red flag in the first place. Driver code, unless implementing interrupt chips or low level hypervisor functionality has absolutely no business with that. Invoking generic_handle_irq() from non interrupt handling context can have nasty side effects at least on x86 due to the hardware trainwreck which makes interrupt affinity changes a fragile beast. Sathyanarayanan triggered a NULL pointer dereference in the low level APIC code that way. While the particular pointer could be checked this would only paper over the issue because there are other ways to trigger warnings or silently corrupt state. Invoke the new irq_inject_interrupt() mechanism, which has the necessary sanity checks in place and injects the interrupt via the irq_retrigger() mechanism, which is at least halfways safe vs. the fragile x86 affinity change mechanics. It's safe on x86 as it does not corrupt state, but it still can cause a premature completion of an interrupt affinity change causing the interrupt line to become stale. Very unlikely, but possible. For regular operations this is a non issue as AER error injection is meant for debugging and testing and not for usage on production systems. People using this should better know what they are doing. Fixes: 390e2db82480 ("PCI/AER: Abstract AER interrupt handling") Reported-by: sathyanarayanan.kuppuswamy@linux.intel.com Signed-off-by: Thomas Gleixner Tested-by: Kuppuswamy Sathyanarayanan Reviewed-by: Kuppuswamy Sathyanarayanan Cc: Bjorn Helgaas Link: https://lkml.kernel.org/r/20200306130624.098374457@linutronix.de --- drivers/pci/pcie/Kconfig | 1 + drivers/pci/pcie/aer_inject.c | 6 ++---- 2 files changed, 3 insertions(+), 4 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig index 6e3c04b46fb1..7876dc4b28f8 100644 --- a/drivers/pci/pcie/Kconfig +++ b/drivers/pci/pcie/Kconfig @@ -34,6 +34,7 @@ config PCIEAER config PCIEAER_INJECT tristate "PCI Express error injection support" depends on PCIEAER + select GENERIC_IRQ_INJECTION help This enables PCI Express Root Port Advanced Error Reporting (AER) software error injector. diff --git a/drivers/pci/pcie/aer_inject.c b/drivers/pci/pcie/aer_inject.c index 6988fe7389b9..21cc3d3387f7 100644 --- a/drivers/pci/pcie/aer_inject.c +++ b/drivers/pci/pcie/aer_inject.c @@ -16,7 +16,7 @@ #include #include -#include +#include #include #include #include @@ -468,9 +468,7 @@ static int aer_inject(struct aer_error_inj *einj) } pci_info(edev->port, "Injecting errors %08x/%08x into device %s\n", einj->cor_status, einj->uncor_status, pci_name(dev)); - local_irq_disable(); - generic_handle_irq(edev->irq); - local_irq_enable(); + ret = irq_inject_interrupt(edev->irq); } else { pci_err(rpdev, "AER device not found\n"); ret = -ENODEV; -- cgit v1.2.3