From: Ma Wupeng mawupeng1@huawei.com

hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9C0QZ

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While testing mlock, we have a problem if the len of mlock is ULONG_MAX. The return value of mlock is zero. But nothing will be locked since the len in do_mlock overflows to zero due to the following code in mlock:

len = PAGE_ALIGN(len + (offset_in_page(start)));

The same problem happens in munlock.

Signed-off-by: Ma Wupeng mawupeng1@huawei.com --- mm/mlock.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c index 4077b1e8e199..d9040aea2be0 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -597,8 +597,6 @@ static int apply_vma_lock_flags(unsigned long start, size_t len, end = start + len; if (end < start) return -EINVAL; - if (end == start) - return 0; vma = find_vma(current->mm, start); if (!vma || vma->vm_start > start) return -ENOMEM; @@ -682,7 +680,13 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla if (!can_do_mlock()) return -EPERM;

+ if (!len) + return 0; + len = PAGE_ALIGN(len + (offset_in_page(start))); + if (!len) + return -EINVAL; + start &= PAGE_MASK;

lock_limit = rlimit(RLIMIT_MEMLOCK); @@ -740,8 +744,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) { int ret;

+ if (!len) + return 0; + len = PAGE_ALIGN(len + (offset_in_page(start))); start &= PAGE_MASK; + if (!len) + return -EINVAL;

if (down_write_killable(&current->mm->mmap_sem)) return -EINTR;