Hi Yang,
On Fri, 1 Oct 2021 at 03:23, Yang Shi <shy828301@xxxxxxxxx> wrote:
>
> When handling shmem page fault the THP with corrupted subpage could be PMD
> mapped if certain conditions are satisfied. But kernel is supposed to
> send SIGBUS when trying to map hwpoisoned page.
>
> There are two paths which may do PMD map: fault around and regular fault.
>
> Before commit f9ce0be71d1f ("mm: Cleanup faultaround and finish_fault() codepaths")
> the thing was even worse in fault around path. The THP could be PMD mapped as
> long as the VMA fits regardless what subpage is accessed and corrupted. After
> this commit as long as head page is not corrupted the THP could be PMD mapped.
>
> In the regular fault path the THP could be PMD mapped as long as the corrupted
> page is not accessed and the VMA fits.
>
> This loophole could be fixed by iterating every subpage to check if any
> of them is hwpoisoned or not, but it is somewhat costly in page fault path.
>
> So introduce a new page flag called HasHWPoisoned on the first tail page. It
> indicates the THP has hwpoisoned subpage(s). It is set if any subpage of THP
> is found hwpoisoned by memory failure and cleared when the THP is freed or
> split.
>
> Fixes: 800d8c63b2e9 ("shmem: add huge pages support")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Suggested-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
> ---
> include/linux/page-flags.h | 19 +++++++++++++++++++
> mm/filemap.c | 12 ++++++------
> mm/huge_memory.c | 2 ++
> mm/memory-failure.c | 6 +++++-
> mm/memory.c | 9 +++++++++
> mm/page_alloc.c | 4 +++-
> 6 files changed, 44 insertions(+), 8 deletions(-)
When CONFIG_MEMORY_FAILURE not set
we get these build failures.
Regression found on x86_64 and i386 gcc-11 builds
Following build warnings / errors reported on Linux mainline master.
metadata:
git_describe: v5.15-559-g19901165d90f
git_repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git_short_log: 19901165d90f (\"Merge tag
'for-5.16/inode-sync-2021-10-29' of git://git.kernel.dk/linux-block\")
target_arch: x86_64
toolchain: gcc-11
In file included from include/linux/mmzone.h:22,
from include/linux/gfp.h:6,
from include/linux/slab.h:15,
from include/linux/crypto.h:20,
from arch/x86/kernel/asm-offsets.c:9:
include/linux/page-flags.h:806:29: error: macro "PAGEFLAG_FALSE"
requires 2 arguments, but only 1 given
806 | PAGEFLAG_FALSE(HasHWPoisoned)
| ^
include/linux/page-flags.h:411: note: macro "PAGEFLAG_FALSE" defined here
411 | #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname,
lname) \
|
include/linux/page-flags.h:807:39: error: macro "TESTSCFLAG_FALSE"
requires 2 arguments, but only 1 given
807 | TESTSCFLAG_FALSE(HasHWPoisoned)
| ^
include/linux/page-flags.h:414: note: macro "TESTSCFLAG_FALSE" defined here
414 | #define TESTSCFLAG_FALSE(uname, lname)
\
|
include/linux/page-flags.h:806:1: error: unknown type name 'PAGEFLAG_FALSE'
806 | PAGEFLAG_FALSE(HasHWPoisoned)
| ^~~~~~~~~~~~~~
include/linux/page-flags.h:807:25: error: expected ';' before 'static'
807 | TESTSCFLAG_FALSE(HasHWPoisoned)
| ^
| ;
......
815 | static inline bool is_page_hwpoison(struct page *page)
| ~~~~~~
make[2]: *** [scripts/Makefile.build:121: arch/x86/kernel/asm-offsets.s] Error 1
Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
build link:
-----------
https://builds.tuxbuild.com/20KPBpXK6K0bKSIKAIKfwlBq7O4/build.log
build config:
-------------
https://builds.tuxbuild.com/20KPBpXK6K0bKSIKAIKfwlBq7O4/config
# To install tuxmake on your system globally
# sudo pip3 install -U tuxmake
tuxmake --runtime podman --target-arch x86_64 --toolchain gcc-11
--kconfig defconfig --kconfig-add
https://builds.tuxbuild.com/20KPBpXK6K0bKSIKAIKfwlBq7O4/config
link:
https://builds.tuxbuild.com/20KPBpXK6K0bKSIKAIKfwlBq7O4/tuxmake_reproducer.sh
--
Linaro LKFT
https://lkft.linaro.org
