316f92a705
Notifier calling chain uses priority to determine the execution
order of the notifiers or listeners registered to the chain.
PCI bus device hot add utilizes the notification mechanism.
The current code sets low priority (INT_MIN) to Intel
dmar_pci_bus_notifier and postpones DMAR decoding after adding
new device into IOMMU. The result is that struct device pointer
cannot be found in DRHD search for the new device's DMAR/IOMMU.
Subsequently, the device is put under the "catch-all" IOMMU
instead of the correct one. This could cause system hang when
device TLB invalidation is sent to the wrong IOMMU. Invalidation
timeout error and hard lockup have been observed and data
inconsistency/crush may occur as well.
This patch fixes the issue by setting a positive priority(1) for
dmar_pci_bus_notifier while the priority of IOMMU bus notifier
uses the default value(0), therefore DMAR decoding will be in
advance of DRHD search for a new device to find the correct IOMMU.
Following is a 2-step example that triggers the bug by simulating
PCI device hot add behavior in Intel Sapphire Rapids server.
echo 1 > /sys/bus/pci/devices/0000:6a:01.0/remove
echo 1 > /sys/bus/pci/rescan
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.