The patch titled
Subject: uprobes: split THPs before trying replace them
has been added to the -mm tree. Its filename is
uprobes-split-thps-before-trying-replace-them.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/uprobes-split-thps-before-trying-replace-them.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/uprobes-split-thps-before-trying-replace-them.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: uprobes: split THPs before trying replace them
For THPs page_check_address() always fails. It leads to endless loop in
uprobe_write_opcode().
Testcase with huge-tmpfs (uprobes cannot probe anonymous memory).
mount -t debugfs none /sys/kernel/debug
mount -t tmpfs -o huge=always none /mnt
gcc -Wall -O2 -o /mnt/test -x c - <<EOF
int main(void)
{
return 0;
}
/* Padding to map the code segment with huge pmd */
asm (".zero 2097152");
EOF
echo 'p /mnt/test:0' > /sys/kernel/debug/tracing/uprobe_events
echo 1 > /sys/kernel/debug/tracing/events/uprobes/enable
/mnt/test
Let's split THPs before trying to replace.
Link: http://lkml.kernel.org/r/20170129173858.45174-2-kirill.shutemov@xxxxxxxxxxxxxxx
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/events/uprobes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN kernel/events/uprobes.c~uprobes-split-thps-before-trying-replace-them kernel/events/uprobes.c
--- a/kernel/events/uprobes.c~uprobes-split-thps-before-trying-replace-them
+++ a/kernel/events/uprobes.c
@@ -300,8 +300,8 @@ int uprobe_write_opcode(struct mm_struct
retry:
/* Read the page with vaddr into memory */
- ret = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &old_page,
- &vma, NULL);
+ ret = get_user_pages_remote(NULL, mm, vaddr, 1,
+ FOLL_FORCE | FOLL_SPLIT, &old_page, &vma, NULL);
if (ret <= 0)
return ret;
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
mm-sleeping-function-called-from-invalid-context-shmem_undo_range.patch
mm-drop-zap_details-ignore_dirty.patch
mm-drop-zap_details-check_swap_entries.patch
mm-drop-unused-argument-of-zap_page_range.patch
oom-reaper-use-madvise_dontneed-logic-to-decide-if-unmap-the-vma.patch
uprobes-split-thps-before-trying-replace-them.patch
mm-introduce-page_vma_mapped_walk.patch
mm-fix-handling-pte-mapped-thps-in-page_referenced.patch
mm-fix-handling-pte-mapped-thps-in-page_idle_clear_pte_refs.patch
mm-rmap-check-all-vmas-that-pte-mapped-thp-can-be-part-of.patch
mm-convert-page_mkclean_one-to-use-page_vma_mapped_walk.patch
mm-convert-try_to_unmap_one-to-use-page_vma_mapped_walk.patch
mm-ksm-convert-write_protect_page-to-use-page_vma_mapped_walk.patch
mm-uprobes-convert-__replace_page-to-use-page_vma_mapped_walk.patch
mm-convert-page_mapped_in_vma-to-use-page_vma_mapped_walk.patch
mm-drop-page_check_address_transhuge.patch
mm-convert-remove_migration_pte-to-use-page_vma_mapped_walk.patch
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