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04f7ce3f07
In pmd/pud_advanced_tests(), the vaddr is aligned up to the next pmd/pud
entry, and so it does not match the given pmdp/pudp and (aligned down)
pfn any more.
For s390, this results in memory corruption, because the IDTE
instruction used e.g. in xxx_get_and_clear() will take the vaddr for
some calculations, in combination with the given pmdp. It will then end
up with a wrong table origin, ending on ...ff8, and some of those
wrongly set low-order bits will also select a wrong pagetable level for
the index addition. IDTE could therefore invalidate (or 0x20) something
outside of the page tables, depending on the wrongly picked index, which
in turn depends on the random vaddr.
As result, we sometimes see "BUG task_struct (Not tainted): Padding
overwritten" on s390, where one 0x5a padding value got overwritten with
0x7a.
Fix this by aligning down, similar to how the pmd/pud_aligned pfns are
calculated.
Link: https://lkml.kernel.org/r/20210525130043.186290-2-gerald.schaefer@linux.ibm.com
Fixes:
|
||
---|---|---|
arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
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 |
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.