[PATCH v6 04/11] mm, arm64: untag user addresses in mm/gup.c
From: Andrey Konovalov <hidden>
Date: 2018-08-30 11:41:31
Also in:
linux-arch, linux-doc, linux-kselftest, linux-mm, lkml
Subsystem:
memory management, memory management - gup (get user pages), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
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 <redacted> --- mm/gup.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/mm/gup.c b/mm/gup.c
index 1abc8b4afff6..6f09132c654e 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; vm_fault_t ret, major = 0; + address = untagged_addr(address); + if (unlocked) fault_flags |= FAULT_FLAG_ALLOW_RETRY;
--
2.19.0.rc0.228.g281dcd1b4d0-goog