Messages in this thread Patch in this message | | | From | Andrey Konovalov <> | Subject | [PATCH v5 04/10] mm, arm64: untag user addresses in mm/gup.c | Date | Mon, 6 Aug 2018 18:40:39 +0200 |
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mm/gup.c provides a kernel interface that accepts user addresses and manipulates user pages directly (for example get_user_pages, that is used by the futex syscall). Since a user can provided tagged addresses, we need to handle such case.
Add untagging to gup.c functions that use user addresses for vma lookup.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- mm/gup.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/mm/gup.c b/mm/gup.c index fc5f98069f4e..ebb87fb56709 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -666,6 +666,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, if (!nr_pages) return 0; + start = untagged_addr(start); + VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); /* @@ -820,6 +822,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, struct vm_area_struct *vma; int ret, major = 0; + address = untagged_addr(address); + if (unlocked) fault_flags |= FAULT_FLAG_ALLOW_RETRY; -- 2.18.0.597.ga71716f1ad-goog
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