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| author | Kees Cook <keescook@chromium.org> | 2018-04-10 16:32:54 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-11 10:28:35 -0700 |
| commit | f6f66c1bf53079ce1f0789c8b482fba35b81617d (patch) | |
| tree | f6660b3a670c905f8f49e68ba6625c39be3bae56 /lib/test_bitmap.c | |
| parent | 5f00ae0d3ef8d36041d8d40ec71ab31b22764cba (diff) | |
| download | lwn-f6f66c1bf53079ce1f0789c8b482fba35b81617d.tar.gz lwn-f6f66c1bf53079ce1f0789c8b482fba35b81617d.zip | |
lib/test_bitmap.c: do not accidentally use stack VLA
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>
Diffstat (limited to 'lib/test_bitmap.c')
| -rw-r--r-- | lib/test_bitmap.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index 413367cf569e..de16f7869fb1 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -296,15 +296,17 @@ static void __init test_bitmap_parselist(void) } } +#define EXP_BYTES (sizeof(exp) * 8) + 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]; - DECLARE_BITMAP(bmap2, len); + DECLARE_BITMAP(bmap2, EXP_BYTES); 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_from_arr32(bmap2, arr, 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", nbits, next_bit); - if (nbits < len - 32) + if (nbits < EXP_BYTES - 32) expect_eq_uint(arr[DIV_ROUND_UP(nbits, 32)], 0xa5a5a5a5); } |