[dpdk-dev] [PATCH v4 0/4] fix creation of duplicate lpm and hash

Olivier Matz olivier.matz at 6wind.com
Wed Apr 6 15:27:57 CEST 2016


Seen while trying to fix the func_reentrancy autotest. The
series addresses several issues:

1/ Hash and lpm return a pointer to an existing object if the user requests the
   creation with an already existing name. This look dangerous: when an object
   is returned, the user does not know if it should be freed or not.

2/ There is a race condition in cuckoo_hash as the lock is not held in
   rte_hash_create(). We could find some cases where NULL is returned when the
   object already exists (ex: when rte_ring_create() fails).

3/ There is a race condition func_reentrancy that can fail even if the tested
   API behaves correctly.


RFC -> v1:

- split the patch in 4 patches
- on error, set rte_errno to EEXIST when relevant
- fix locking in cuckoo_hash creation

v1 -> v2:

- fix compilation issue in cuckoo hash
- update the hash test to conform to the new behavior
- rework locking modification in cuckoo_hash
- passed autotests: hash, lpm, lpm6, func_reentrancy

v2 -> v3:

- rebase against head
- add "Fixes:" in commit messages
- properly set lpm or hash pointers to NULL on error before returning

v3 -> v4:

- add entries in the release note to explain the API changes
  in lpm and hash
- correct the "Fixes:" line in the first 2 patches

Olivier Matz (4):
  lpm: allocation of an existing object should fail
  hash: allocation of an existing object should fail
  hash: keep the list locked at creation
  autotest: fix func reentrancy

 app/test/test_func_reentrancy.c        | 31 ++++++++++-----
 app/test/test_hash.c                   | 65 +++++++++++-------------------
 app/test/test_lpm6.c                   |  2 +-
 doc/guides/rel_notes/release_16_04.rst | 17 ++++++++
 lib/librte_hash/rte_cuckoo_hash.c      | 72 ++++++++++++++++++++--------------
 lib/librte_hash/rte_fbk_hash.c         |  5 ++-
 lib/librte_lpm/rte_lpm.c               | 10 ++++-
 lib/librte_lpm/rte_lpm6.c              |  5 ++-
 8 files changed, 120 insertions(+), 87 deletions(-)

-- 
2.1.4



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