mm: mremap: fix sign for EFAULT error return value

The mremap syscall is supposed to return a pointer to the new virtual
memory area on success, and a negative value of the error code in case of
failure.  Currently, EFAULT is returned when the VMA is not found, instead
of -EFAULT.  The users of this syscall will therefore believe the syscall
succeeded in case the VMA didn't exist, as it returns a pointer to address
0xe (0xe being the value of EFAULT).  Fix the sign of the error value.

Link: https://lkml.kernel.org/r/20220427224439.23828-2-dossche.niels@gmail.com
Fixes: 550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed vma")
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/mremap.c b/mm/mremap.c
index 303d329..0b93fac 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -947,7 +947,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
                return -EINTR;
        vma = vma_lookup(mm, addr);
        if (!vma) {
-               ret = EFAULT;
+               ret = -EFAULT;
                goto out;
        }