**diff options**

author | Adam Buchbinder <abuchbinder@google.com> | 2014-06-13 14:18:50 -0700 |
---|---|---|

committer | David Sterba <dsterba@suse.cz> | 2014-08-22 14:39:34 +0200 |

commit | c9951e2269fb3e3db1546d8627bc34a414ed13bd (patch) | |

tree | 97508a459884844af1a2095131a8cdf227808e02 /radix-tree.c | |

parent | 5351d29eef4c26e9ffabc2bae0433407953fd8e0 (diff) |

btrfs-progs: Fix undefined behavior in radix-tree.c.

When running with UndefinedBehaviorSanitizer, the tests produce the following
error:
radix-tree.c:836:30: runtime error: shift exponent 18446744073709551613
is too large for 64-bit type 'unsigned long'
(That's a negative shift exponent represented as an unsigned long.)
Even though the value is discarded in those cases, it's still undefined
behavior; see the C99 standard, section 6.5.7, paragraph three: "If the
value of the right operand is negative [...] the behavior is undefined."
Signed-off-by: Adam Buchbinder <abuchbinder@google.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

Diffstat (limited to 'radix-tree.c')

-rw-r--r-- | radix-tree.c | 6 |

1 files changed, 3 insertions, 3 deletions

diff --git a/radix-tree.c b/radix-tree.c index 4f295fcf..74579449 100644 --- a/radix-tree.c +++ b/radix-tree.c @@ -833,10 +833,10 @@ int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) static unsigned long __maxindex(unsigned int height) { unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; - unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; + unsigned long index = ~0UL; - if (tmp >= RADIX_TREE_INDEX_BITS) - index = ~0UL; + if (tmp < RADIX_TREE_INDEX_BITS) + index = (index >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; return index; } |