[PATCH v4 00/30] Support recursive-read lock deadlock detection

[Yuyang Du]

Hi Peter and Ingo,

This patchset proposes a general read-write lock deadlock detection
algorithm on the premise that exclusive locks can be seen as a
special/partial usage of read-write locks. The current Linux kernel
locks are all considered in this algorithm. Prominently, the
recursive-read lock can be well supported, which has not been for more
than a decade.

The bulk of the algorithm is in patch #27. Now that the recursive-read
locks are suppported, we have all the 262 cases passed.

Please, some of the minor fix and/or no-functional-change patches may
be reviewed at least.


Changes from v3:

 - Reworded some changelogs
 - Rebased to current code base
 - Per Boqun's suggestion, reordered patches
 - Much more time elapsed

Changes from v2:

 - Handle correctly rwsem locks hopefully.
 - Remove indirect dependency redundancy check.
 - Check direct dependency redundancy before validation.
 - Compose lock chains for those with trylocks or separated by trylocks.
 - Map lock dependencies to lock chains.
 - Consolidate forward and backward lock_lists.
 - Clearly and formally define two-task model for lockdep.


--

Yuyang Du (30):
  locking/lockdep: Rename deadlock check functions
  locking/lockdep: Change return type of add_chain_cache()
  locking/lockdep: Change return type of lookup_chain_cache_add()
  locking/lockdep: Pass lock chain from validate_chain() to
    check_prev_add()
  locking/lockdep: Add lock chain list_head field in struct lock_list
    and lock_chain
  locking/lockdep: Update comments in struct lock_list and held_lock
  locking/lockdep: Remove indirect dependency redundancy check
  locking/lockdep: Skip checks if direct dependency is already present
  locking/lockdep: Remove chain_head argument in validate_chain()
  locking/lockdep: Remove useless lock type assignment
  locking/lockdep: Remove irq-safe to irq-unsafe read check
  locking/lockdep: Specify the depth of current lock stack in
    lookup_chain_cache_add()
  locking/lockdep: Treat every lock dependency as in a new lock chain
  locking/lockdep: Combine lock_lists in struct lock_class into an array
  locking/lockdep: Consolidate forward and backward lock_lists into one
  locking/lockdep: Add lock chains to direct lock dependency graph
  locking/lockdep: Use lock type enum to explicitly specify read or
    write locks
  ocking/lockdep: Add read-write type for a lock dependency
  locking/lockdep: Add helper functions to operate on the searched path
  locking/lockdep: Update direct dependency's read-write type if it
    exists
  locking/lockdep: Introduce chain_hlocks_type for held lock's
    read-write type
  locking/lockdep: Hash held lock's read-write type into chain key
  locking/lockdep: Adjust BFS algorithm to support multiple matches
  locking/lockdep: Define the two task model for lockdep checks formally
  locking/lockdep: Introduce mark_lock_unaccessed()
  locking/lockdep: Add nest lock type
  locking/lockdep: Add lock exclusiveness table
  locking/lockdep: Support read-write lock's deadlock detection
  locking/lockdep: Adjust selftest case for recursive read lock
  locking/lockdep: Add more lockdep selftest cases

 include/linux/lockdep.h            |   91 ++-
 include/linux/rcupdate.h           |    2 +-
 kernel/locking/lockdep.c           | 1227 ++++++++++++++++++++++++------------
 kernel/locking/lockdep_internals.h |    3 +-
 kernel/locking/lockdep_proc.c      |    8 +-
 lib/locking-selftest.c             | 1109 +++++++++++++++++++++++++++++++-
 6 files changed, 1981 insertions(+), 459 deletions(-)

-- 
1.8.3.1