Messages in this thread | | | From | Naresh Kamboju <> | Date | Tue, 2 Nov 2021 00:35:34 +0530 | Subject | Re: [v3 PATCH 2/5] mm: filemap: check if THP has hwpoisoned subpage for PMD page fault |
| |
Hi Yang,
On Fri, 1 Oct 2021 at 03:23, Yang Shi <shy828301@gmail.com> 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@vger.kernel.org> > Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Signed-off-by: Yang Shi <shy828301@gmail.com> > --- > 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@linaro.org>
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
| |