linux_dsm_epyc7002/drivers/pci/pcie
Thomas Gleixner 9ae0522537 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: 390e2db824 ("PCI/AER: Abstract AER interrupt handling")
Reported-by: sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lkml.kernel.org/r/20200306130624.098374457@linutronix.de
2020-03-08 11:07:12 +01:00
..
aer_inject.c PCI/AER: Fix the broken interrupt injection 2020-03-08 11:07:12 +01:00
aer.c PCI/AER: Initialize aer_fifo 2020-01-23 16:40:03 -06:00
aspm.c PCI/ASPM: Remove PCIEASPM_DEBUG Kconfig option and related code 2019-11-21 17:31:46 -06:00
bw_notification.c pci-v5.2-changes 2019-05-14 10:30:10 -07:00
dpc.c PCI/DPC: Add "pcie_ports=dpc-native" to allow DPC without AER control 2019-10-25 15:11:43 -05:00
err.c PCI/AER: Factor message prefixes with dev_fmt() 2020-01-23 16:39:53 -06:00
Kconfig PCI/AER: Fix the broken interrupt injection 2020-03-08 11:07:12 +01:00
Makefile PCI/LINK: Add Kconfig option (default off) 2019-05-02 08:34:32 -05:00
pme.c PCI/PME: Replace dev_printk(KERN_DEBUG) with dev_info() 2019-05-09 16:27:29 -05:00
portdrv_core.c PCI/DPC: Add "pcie_ports=dpc-native" to allow DPC without AER control 2019-10-25 15:11:43 -05:00
portdrv_pci.c PCI/DPC: Add "pcie_ports=dpc-native" to allow DPC without AER control 2019-10-25 15:11:43 -05:00
portdrv.h PCI/DPC: Add "pcie_ports=dpc-native" to allow DPC without AER control 2019-10-25 15:11:43 -05:00
ptm.c PCI/PTM: Remove spurious "d" from granularity message 2019-11-21 07:52:32 -06:00