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lib/test_bitmap.c: do not accidentally use stack VLA

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This avoids an accidental stack VLA (since the compiler thinks the value
of "len" can change, even when marked "const").  This just replaces it
with a #define so it will DTRT.

Seen with -Wvla.  Fixed as part of the directive to remove all VLAs from
the kernel: https://lkml.org/lkml/2018/3/7/621

Link: http://lkml.kernel.org/r/20180307212555.GA17927@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Yury Norov <ynorov@caviumnetworks.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kees Cook
2018-04-10 16:32:54 -07:00
committed by Linus Torvalds
parent 5f00ae0d3e
commit f6f66c1bf5
1 changed files with 6 additions and 4 deletions
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10
lib/test_bitmap.c
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@@ -296,15 +296,17 @@ static void __init test_bitmap_parselist(void)
} }
} }
#define EXP_BYTES (sizeof(exp) * 8)
static void __init test_bitmap_arr32(void) static void __init test_bitmap_arr32(void)
{ {
unsigned int nbits, next_bit, len = sizeof(exp) * 8; unsigned int nbits, next_bit;
u32 arr[sizeof(exp) / 4]; u32 arr[sizeof(exp) / 4];
DECLARE_BITMAP(bmap2, len); DECLARE_BITMAP(bmap2, EXP_BYTES);
memset(arr, 0xa5, sizeof(arr)); memset(arr, 0xa5, sizeof(arr));
for (nbits = 0; nbits < len; ++nbits) { for (nbits = 0; nbits < EXP_BYTES; ++nbits) {
bitmap_to_arr32(arr, exp, nbits); bitmap_to_arr32(arr, exp, nbits);
bitmap_from_arr32(bmap2, arr, nbits); bitmap_from_arr32(bmap2, arr, nbits);
expect_eq_bitmap(bmap2, exp, nbits); expect_eq_bitmap(bmap2, exp, nbits);
@@ -316,7 +318,7 @@ static void __init test_bitmap_arr32(void)
" tail is not safely cleared: %d\n", " tail is not safely cleared: %d\n",
nbits, next_bit); nbits, next_bit);
if (nbits < len - 32) if (nbits < EXP_BYTES - 32)
expect_eq_uint(arr[DIV_ROUND_UP(nbits, 32)], expect_eq_uint(arr[DIV_ROUND_UP(nbits, 32)],
0xa5a5a5a5); 0xa5a5a5a5);
} }