Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+28
-9
+28
-9
lib/test_user_copy.c
+28
-9
lib/test_user_copy.c
···
47
47
static int test_check_nonzero_user(char *kmem, char __user *umem, size_t size)
48
48
{
49
49
int ret = 0;
50
-
size_t start, end, i;
51
-
size_t zero_start = size / 4;
52
-
size_t zero_end = size - zero_start;
50
+
size_t start, end, i, zero_start, zero_end;
51
+
52
+
if (test(size < 2 * PAGE_SIZE, "buffer too small"))
53
+
return -EINVAL;
53
54
54
55
/*
55
-
* We conduct a series of check_nonzero_user() tests on a block of memory
56
-
* with the following byte-pattern (trying every possible [start,end]
57
-
* pair):
56
+
* We want to cross a page boundary to exercise the code more
57
+
* effectively. We also don't want to make the size we scan too large,
58
+
* otherwise the test can take a long time and cause soft lockups. So
59
+
* scan a 1024 byte region across the page boundary.
60
+
*/
61
+
size = 1024;
62
+
start = PAGE_SIZE - (size / 2);
63
+
64
+
kmem += start;
65
+
umem += start;
66
+
67
+
zero_start = size / 4;
68
+
zero_end = size - zero_start;
69
+
70
+
/*
71
+
* We conduct a series of check_nonzero_user() tests on a block of
72
+
* memory with the following byte-pattern (trying every possible
73
+
* [start,end] pair):
58
74
*
59
75
* [ 00 ff 00 ff ... 00 00 00 00 ... ff 00 ff 00 ]
60
76
*
61
-
* And we verify that check_nonzero_user() acts identically to memchr_inv().
77
+
* And we verify that check_nonzero_user() acts identically to
78
+
* memchr_inv().
62
79
*/
63
80
64
81
memset(kmem, 0x0, size);
···
110
93
size_t ksize, usize;
111
94
112
95
umem_src = kmalloc(size, GFP_KERNEL);
113
-
if ((ret |= test(umem_src == NULL, "kmalloc failed")))
96
+
ret = test(umem_src == NULL, "kmalloc failed");
97
+
if (ret)
114
98
goto out_free;
115
99
116
100
expected = kmalloc(size, GFP_KERNEL);
117
-
if ((ret |= test(expected == NULL, "kmalloc failed")))
101
+
ret = test(expected == NULL, "kmalloc failed");
102
+
if (ret)
118
103
goto out_free;
119
104
120
105
/* Fill umem with a fixed byte pattern. */