mm/madvise: handle madvise_lock() failure during race unwinding

When unwinding race on -ERESTARTNOINTR handling of process_madvise(),
madvise_lock() failure is ignored.  Check the failure and abort remaining
works in the case.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 4000e3d ("mm/madvise: remove redundant mmap_lock operations from process_madvise()")
Signed-off-by: SeongJae Park <[email protected]>
Reported-by: Barry Song <[email protected]>
Closes: https://lore.kernel.org/CAGsJ_4xJXXO0G+4BizhohSZ4yDteziPw43_uF8nPXPWxUVChzw@mail.gmail.com
Reviewed-by: Jann Horn <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Reviewed-by: Barry Song <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: sjp38

mm/madvise.c

@@ -1881,7 +1881,9 @@ static ssize_t vector_madvise(struct mm_struct *mm, struct iov_iter *iter,
 			/* Drop and reacquire lock to unwind race. */
 			madvise_finish_tlb(&madv_behavior);
 			madvise_unlock(mm, behavior);
-			madvise_lock(mm, behavior);
+			ret = madvise_lock(mm, behavior);
+			if (ret)
+				goto out;
 			madvise_init_tlb(&madv_behavior, mm);
 			continue;
 		}
@@ -1892,6 +1894,7 @@ static ssize_t vector_madvise(struct mm_struct *mm, struct iov_iter *iter,
 	madvise_finish_tlb(&madv_behavior);
 	madvise_unlock(mm, behavior);
 
+out:
 	ret = (total_len - iov_iter_count(iter)) ? : ret;
 
 	return ret;