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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2021-07-27 18:01:32 +0300 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2021-07-29 09:52:33 +0200 |
| commit | fe8e3ee0d588566c1f44f28a555042ef50eba491 (patch) | |
| tree | a45d41c48935380439bac842d5d472458c3efc0c | |
| parent | e563592c3e4296780e5a184a917b8b86e126f0b3 (diff) | |
| download | lwn-fe8e3ee0d588566c1f44f28a555042ef50eba491.tar.gz lwn-fe8e3ee0d588566c1f44f28a555042ef50eba491.zip | |
lib/test_scanf: Handle n_bits == 0 in random tests
UBSAN reported (via LKP)
[ 11.021349][ T1] UBSAN: shift-out-of-bounds in lib/test_scanf.c:275:51
[ 11.022782][ T1] shift exponent 32 is too large for 32-bit type 'unsigned int'
When n_bits == 0, the shift is out of range. Switch code to use GENMASK
to handle this case.
Fixes: 50f530e176ea ("lib: test_scanf: Add tests for sscanf number conversion")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210727150132.28920-1-andriy.shevchenko@linux.intel.com
| -rw-r--r-- | lib/test_scanf.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/lib/test_scanf.c b/lib/test_scanf.c index 48ff5747a4da..6a828dfc8ea1 100644 --- a/lib/test_scanf.c +++ b/lib/test_scanf.c @@ -271,7 +271,7 @@ static u32 __init next_test_random(u32 max_bits) { u32 n_bits = hweight32(prandom_u32_state(&rnd_state)) % (max_bits + 1); - return prandom_u32_state(&rnd_state) & (UINT_MAX >> (32 - n_bits)); + return prandom_u32_state(&rnd_state) & GENMASK(n_bits, 0); } static unsigned long long __init next_test_random_ull(void) @@ -280,7 +280,7 @@ static unsigned long long __init next_test_random_ull(void) u32 n_bits = (hweight32(rand1) * 3) % 64; u64 val = (u64)prandom_u32_state(&rnd_state) * rand1; - return val & (ULLONG_MAX >> (64 - n_bits)); + return val & GENMASK_ULL(n_bits, 0); } #define random_for_type(T) \ |