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authorAlexander Lobakin <alexandr.lobakin@intel.com>2022-07-11 20:09:29 +0200
committerYury Norov <yury.norov@gmail.com>2022-07-12 08:00:50 -0700
commit428bc098635680a664779f26f24fe9197d186172 (patch)
tree97d3d4a3edbdce777501739e5da830efd461957c
parentdc34d5036692c614eef23c1130ee42a201c316bf (diff)
lib/bitmap: fix off-by-one in bitmap_to_arr64()
GENMASK*() family takes the first and the last bits of the mask *including* them. So, with the current code bitmap_to_arr64() doesn't clear the tail properly: nbits % exp mask must be 1 GENMASK(1, 0) 0x3 0x1 ... 63 GENMASK(63, 0) 0xffffffffffffffff 0x7fffffffffffffff This was found by making the function always available instead of 32-bit BE systems only (for reusing in some new functionality). Turn the number of bits into the last bit set by subtracting 1. @nbits is already checked to be positive beforehand. Fixes: 0a97953fd221 ("lib: add bitmap_{from,to}_arr64") Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Yury Norov <yury.norov@gmail.com>
-rw-r--r--lib/bitmap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index b18e31ea6e66..e903e13c62e1 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -1564,7 +1564,7 @@ void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
/* Clear tail bits in the last element of array beyond nbits. */
if (nbits % 64)
- buf[-1] &= GENMASK_ULL(nbits % 64, 0);
+ buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);
}
EXPORT_SYMBOL(bitmap_to_arr64);
#endif