The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
Possible dependencies:
ab0c3f1251b4 ("mm/khugepaged: fix collapse_pte_mapped_thp() to allow anon_vma")
8d3c106e19e8 ("mm/khugepaged: take the right locks for page table retraction")
34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE")
58ac9a8993a1 ("mm/khugepaged: attempt to map file/shmem-backed pte-mapped THPs by pmds")
780a4b6fb865 ("mm/khugepaged: check compound_order() in collapse_pte_mapped_thp()")
b26e27015ec9 ("mm: thp: convert to use common struct mm_slot")
685405020b9f ("mm/khugepaged: stop using vma linked list")
7d2c4385c341 ("mm/khugepaged: rename prefix of shared collapse functions")
7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse")
507228044236 ("mm/khugepaged: record SCAN_PMD_MAPPED when scan_pmd() finds hugepage")
a7f4e6e4c47c ("mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()")
50ad2f24b3b4 ("mm/khugepaged: propagate enum scan_result codes back to callers")
9710a78ab2ae ("mm/khugepaged: dedup and simplify hugepage alloc and charging")
34d6b470ab9c ("mm/khugepaged: add struct collapse_control")
c6a7f445a272 ("mm: khugepaged: don't carry huge page to the next loop for !CONFIG_NUMA")
1064026bab9f ("mm: khugepaged: reorg some khugepaged helpers")
7da4e2cb8b1f ("mm: thp: kill __transhuge_page_enabled()")
9fec51689ff6 ("mm: thp: kill transparent_hugepage_active()")
f707fa493784 ("mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate")
4fa6893faeaa ("mm: thp: consolidate vma size check to transhuge_vma_suitable")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ab0c3f1251b4670978fde0bd54161795a139b060 Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd(a)google.com>
Date: Thu, 22 Dec 2022 12:41:50 -0800
Subject: [PATCH] mm/khugepaged: fix collapse_pte_mapped_thp() to allow
anon_vma
uprobe_write_opcode() uses collapse_pte_mapped_thp() to restore huge pmd,
when removing a breakpoint from hugepage text: vma->anon_vma is always set
in that case, so undo the prohibition. And MADV_COLLAPSE ought to be able
to collapse some page tables in a vma which happens to have anon_vma set
from CoWing elsewhere.
Is anon_vma lock required? Almost not: if any page other than expected
subpage of the non-anon huge page is found in the page table, collapse is
aborted without making any change. However, it is possible that an anon
page was CoWed from this extent in another mm or vma, in which case a
concurrent lookup might look here: so keep it away while clearing pmd (but
perhaps we shall go back to using pmd_lock() there in future).
Note that collapse_pte_mapped_thp() is exceptional in freeing a page table
without having cleared its ptes: I'm uneasy about that, and had thought
pte_clear()ing appropriate; but exclusive i_mmap lock does fix the
problem, and we would have to move the mmu_notification if clearing those
ptes.
What this fixes is not a dangerous instability. But I suggest Cc stable
because uprobes "healing" has regressed in that way, so this should follow
8d3c106e19e8 into those stable releases where it was backported (and may
want adjustment there - I'll supply backports as needed).
Link: https://lkml.kernel.org/r/b740c9fb-edba-92ba-59fb-7a5592e5dfc@google.com
Fixes: 8d3c106e19e8 ("mm/khugepaged: take the right locks for page table retraction")
Signed-off-by: Hugh Dickins <hughd(a)google.com>
Acked-by: David Hildenbrand <david(a)redhat.com>
Cc: Jann Horn <jannh(a)google.com>
Cc: Yang Shi <shy828301(a)gmail.com>
Cc: Zach O'Keefe <zokeefe(a)google.com>
Cc: Song Liu <songliubraving(a)fb.com>
Cc: <stable(a)vger.kernel.org> [5.4+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 5cb401aa2b9d..9a0135b39b19 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1460,14 +1460,6 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
if (!hugepage_vma_check(vma, vma->vm_flags, false, false, false))
return SCAN_VMA_CHECK;
- /*
- * Symmetry with retract_page_tables(): Exclude MAP_PRIVATE mappings
- * that got written to. Without this, we'd have to also lock the
- * anon_vma if one exists.
- */
- if (vma->anon_vma)
- return SCAN_VMA_CHECK;
-
/* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
if (userfaultfd_wp(vma))
return SCAN_PTE_UFFD_WP;
@@ -1567,8 +1559,14 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
}
/* step 4: remove pte entries */
+ /* we make no change to anon, but protect concurrent anon page lookup */
+ if (vma->anon_vma)
+ anon_vma_lock_write(vma->anon_vma);
+
collapse_and_free_pmd(mm, vma, haddr, pmd);
+ if (vma->anon_vma)
+ anon_vma_unlock_write(vma->anon_vma);
i_mmap_unlock_write(vma->vm_file->f_mapping);
maybe_install_pmd:
Dzień dobry,
zapoznałem się z Państwa ofertą i z przyjemnością przyznaję, że przyciąga uwagę i zachęca do dalszych rozmów.
Pomyślałem, że może mógłbym mieć swój wkład w Państwa rozwój i pomóc dotrzeć z tą ofertą do większego grona odbiorców. Pozycjonuję strony www, dzięki czemu generują świetny ruch w sieci.
Możemy porozmawiać w najbliższym czasie?
Pozdrawiam
Adam Charachuta
Backport of:
commit 0d362be5b142 ("Makefile: link with -z noexecstack --no-warn-rwx-segments")
breaks arm64 Build ID when CONFIG_MODVERSIONS=y for all kernels
from: commit e4484a495586 ("Merge tag 'kbuild-fixes-v5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild")
until: commit df202b452fe6 ("Merge tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild")
Linus's tree doesn't have this issue since 0d362be5b142 was merged
after df202b452fe6 which included:
commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS")
This kernel's KBUILD CONFIG_MODVERSIONS tooling compiles and links .S targets
with relocatable (-r) and now (-z noexecstack)
which results in ld adding a .note.GNU-stack section to .o files.
Final linking of vmlinux should add a .NOTES segment containing the
Build ID, but does NOT (on some architectures like arm64) if a
.note.GNU-stack section is found in .o's supplied during link
of vmlinux.
DISCARD .note.GNU-stack sections of .S targets. Final link of
vmlinux then properly adds .NOTES segment containing Build ID that can
be read using tools like 'readelf -n'.
Fixes: 0d362be5b142 ("Makefile: link with -z noexecstack --no-warn-rwx-segments")
Cc: <stable(a)vger.kernel.org> # 5.15, 5.10, 5.4
Cc: <linux-kbuild(a)vger.kernel.org>
Cc: Nick Desaulniers <ndesaulniers(a)google.com>
Cc: Masahiro Yamada <masahiroy(a)kernel.org>
Cc: Nicholas Piggin <npiggin(a)gmail.com>
Cc: Michal Marek <michal.lkml(a)markovi.net>
Cc: Nathan Chancellor <nathan(a)kernel.org>
Signed-off-by: Tom Saeger <tom.saeger(a)oracle.com>
---
v2:
- Changed approach to append DISCARD section to generated linker script.
- ld no longer emits warning (which was intent of 0d362b35b142) this
addresses Nick's v1 feedback.
- this is applied to all arches, not just arm64
- added commit refs and notes why this doesn't occur in Linus's tree
to address Greg's v1 feedback.
- added Fixes: 0d362b35b142 requested by Nick
- added note to changelog for 7b4537199a4a requested by Nick
- build tested on arm64 and x86
version works(vmlinux contains Build ID)
v4.14.302 x86, arm64
v4.14.302.patched x86, arm64
v4.19.269 x86, arm64
v4.19.269.patched x86, arm64
v5.4.227 x86
v5.4.227.patched x86, arm64
v5.10.159 x86
v5.10.159.patched x86, arm64
v5.15.83 x86
v5.15.83.patched x86, arm64
v1: https://lore.kernel.org/all/cover.1670358255.git.tom.saeger@oracle.com/
scripts/Makefile.build | 2 ++
1 file changed, 2 insertions(+)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 17aa8ef2d52a..e3939676eeb5 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -379,6 +379,8 @@ cmd_modversions_S = \
if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
> $(@D)/.tmp_$(@F:.o=.ver); \
+ echo "SECTIONS { /DISCARD/ : { *(.note.GNU-stack) } }" \
+ >> $(@D)/.tmp_$(@F:.o=.ver); \
\
$(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
-T $(@D)/.tmp_$(@F:.o=.ver); \
base-commit: fd6d66840b4269da4e90e1ea807ae3197433bc66
--
2.38.1