diff options
| author | Alex Zhang <zhangalex@google.com> | 2020-08-06 23:22:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-07 11:33:26 -0700 |
| commit | 0c4123e3fb82d6014d0a70b52eb38153f658541c (patch) | |
| tree | 5c656de44bab39604512c9438a665f657b09aec6 /mm/memory.c | |
| parent | 463b7a173d52f0b15473171fe895ab3a3d852a5e (diff) | |
| download | lwn-0c4123e3fb82d6014d0a70b52eb38153f658541c.tar.gz lwn-0c4123e3fb82d6014d0a70b52eb38153f658541c.zip | |
mm/memory.c: make remap_pfn_range() reject unaligned addr
This function implicitly assumes that the addr passed in is page aligned.
A non page aligned addr could ultimately cause a kernel bug in
remap_pte_range as the exit condition in the logic loop may never be
satisfied. This patch documents the need for the requirement, as well as
explicitly adds a check for it.
Signed-off-by: Alex Zhang <zhangalex@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200617233512.177519-1-zhangalex@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c index f4f27b9d48c5..c39a13b09602 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2082,7 +2082,7 @@ static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, /** * remap_pfn_range - remap kernel memory to userspace * @vma: user vma to map to - * @addr: target user address to start at + * @addr: target page aligned user address to start at * @pfn: page frame number of kernel physical memory address * @size: size of mapping area * @prot: page protection flags for this mapping @@ -2101,6 +2101,9 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, unsigned long remap_pfn = pfn; int err; + if (WARN_ON_ONCE(!PAGE_ALIGNED(addr))) + return -EINVAL; + /* * Physically remapped pages are special. Tell the * rest of the world about it: |