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Date: Thu, 05 Sep 2019 15:40:44 +0000
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Subject: [dpdk-dev] [Bug 345] rte_hash returns invalid key if the number of
 entries is not a power of 2
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https://bugs.dpdk.org/show_bug.cgi?id=3D345

            Bug ID: 345
           Summary: rte_hash returns invalid key if the number of entries
                    is not a power of 2
           Product: DPDK
           Version: 19.08
          Hardware: All
                OS: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: other
          Assignee: dev@dpdk.org
          Reporter: barbette@kth.se
  Target Milestone: ---

Hi all,

rte_hash_create will silently augment the number of entries (N) to the next
power of 2 value.

Per the documentation, the return values of "rte_hash_lookup" or "rte_hash_=
add"
is "[... or] a positive value that can be used by the caller as an offset i=
nto
an array of user data. This value is unique for this key.".
Which may lead to a segmentation fault, as the user allocated only N entries
and not next_pow2(N). And there is no means to recover what is the "final"
number of entries (next_pow2(N)).

I would suggest to at least update the documentation. One way to really fix
this would be to let the user get the actual number of entries, or fail if =
the
value is not a power of 2.

Tom

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