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authorLinus Torvalds <torvalds@linux-foundation.org>2019-10-18 18:19:04 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2019-10-18 18:19:04 -0400
commit8eb4b3b0dd9ae3e5399ff902da87d13740a2b70f (patch)
treeb4660fe0fbd97aee24f1e9f7961815c34ce808b6 /lib
parent7571438a4868e7cb09d698ab52e54f9722020eef (diff)
parentf418dddffc8007945fd5962380ebde770a240cf5 (diff)
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Merge tag 'copy-struct-from-user-v5.4-rc4' of gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux
Pull usercopy test fixlets from Christian Brauner: "This contains two improvements for the copy_struct_from_user() tests: - a coding style change to get rid of the ugly "if ((ret |= test()))" pointed out when pulling the original patchset. - avoid a soft lockups when running the usercopy tests on machines with large page sizes by scanning only a 1024 byte region" * tag 'copy-struct-from-user-v5.4-rc4' of gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux: usercopy: Avoid soft lockups in test_check_nonzero_user() lib: test_user_copy: style cleanup
Diffstat (limited to 'lib')
-rw-r--r--lib/test_user_copy.c37
1 files changed, 28 insertions, 9 deletions
diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
index e365ace06538..5ff04d8fe971 100644
--- a/lib/test_user_copy.c
+++ b/lib/test_user_copy.c
@@ -47,18 +47,35 @@ static bool is_zeroed(void *from, size_t size)
static int test_check_nonzero_user(char *kmem, char __user *umem, size_t size)
{
int ret = 0;
- size_t start, end, i;
- size_t zero_start = size / 4;
- size_t zero_end = size - zero_start;
+ size_t start, end, i, zero_start, zero_end;
+
+ if (test(size < 2 * PAGE_SIZE, "buffer too small"))
+ return -EINVAL;
+
+ /*
+ * We want to cross a page boundary to exercise the code more
+ * effectively. We also don't want to make the size we scan too large,
+ * otherwise the test can take a long time and cause soft lockups. So
+ * scan a 1024 byte region across the page boundary.
+ */
+ size = 1024;
+ start = PAGE_SIZE - (size / 2);
+
+ kmem += start;
+ umem += start;
+
+ zero_start = size / 4;
+ zero_end = size - zero_start;
/*
- * We conduct a series of check_nonzero_user() tests on a block of memory
- * with the following byte-pattern (trying every possible [start,end]
- * pair):
+ * We conduct a series of check_nonzero_user() tests on a block of
+ * memory with the following byte-pattern (trying every possible
+ * [start,end] pair):
*
* [ 00 ff 00 ff ... 00 00 00 00 ... ff 00 ff 00 ]
*
- * And we verify that check_nonzero_user() acts identically to memchr_inv().
+ * And we verify that check_nonzero_user() acts identically to
+ * memchr_inv().
*/
memset(kmem, 0x0, size);
@@ -93,11 +110,13 @@ static int test_copy_struct_from_user(char *kmem, char __user *umem,
size_t ksize, usize;
umem_src = kmalloc(size, GFP_KERNEL);
- if ((ret |= test(umem_src == NULL, "kmalloc failed")))
+ ret = test(umem_src == NULL, "kmalloc failed");
+ if (ret)
goto out_free;
expected = kmalloc(size, GFP_KERNEL);
- if ((ret |= test(expected == NULL, "kmalloc failed")))
+ ret = test(expected == NULL, "kmalloc failed");
+ if (ret)
goto out_free;
/* Fill umem with a fixed byte pattern. */