mm: respect arch_dup_mmap() return value

Commit 1536f4900e33 ("include/linux/sched/mm.h: uninline mmdrop_async(),
etc") ignored the return value of arch_dup_mmap(). As a result, on x86,
a failure to duplicate the LDT (e.g. due to memory allocation error)
would leave the duplicated memory mapping in an inconsistent state.

Fix by using the return value, as it was before the change.

Link: http://lkml.kernel.org/r/20180823051229.211856-1-namit@vmware.com
Fixes: 1536f4900e33a ("include/linux/sched/mm.h: uninline mmdrop_async(), etc")
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/fork.c b/kernel/fork.c
index d896e9ca38b0cccc5de00a0564ecd22179fa2c06..f0b58479534f07dfd55d57a117b4055d80c829b5 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -550,8 +550,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
                        goto out;
        }
        /* a new mm has just been created */
-       arch_dup_mmap(oldmm, mm);
-       retval = 0;
+       retval = arch_dup_mmap(oldmm, mm);
 out:
        up_write(&mm->mmap_sem);
        flush_tlb_mm(oldmm);