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On systems with hardware dirty bit management, the ltp madvise09 unit
test fails due to dirty bit information being lost and pages being
incorrectly freed.
This was bisected to:
arm64: Ignore hardware dirty bit updates in ptep_set_wrprotect()
Reverting this commit leads to a separate problem, that the unit test
retains pages that should have been dropped due to the function
madvise_free_pte_range(.) not cleaning pte's properly.
Currently pte_mkclean only clears the software dirty bit, thus the
following code sequence can appear:
pte = pte_mkclean(pte);
if (pte_dirty(pte))
// this condition can return true with HW DBM!
This patch also adjusts pte_mkclean to set PTE_RDONLY thus effectively
clearing both the SW and HW dirty information.
In order for this to function on systems without HW DBM, we need to
also adjust pte_mkdirty to remove the read only bit from writable pte's
to avoid infinite fault loops.
Cc: <stable@vger.kernel.org>
Fixes:
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.