1. 14 Jul, 2006 2 commits
  2. 03 Jul, 2006 11 commits
    • Ingo Molnar's avatar
      [PATCH] lockdep: kconfig · 4d9f34ad
      Ingo Molnar authored
      Offer the following lock validation options:
      
       CONFIG_PROVE_LOCKING
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      4d9f34ad
    • Ingo Molnar's avatar
      [PATCH] lockdep: prove spinlock rwlock locking correctness · 8a25d5de
      Ingo Molnar authored
      Use the lock validator framework to prove spinlock and rwlock locking
      correctness.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      8a25d5de
    • Ingo Molnar's avatar
      [PATCH] lockdep: prove rwsem locking correctness · 4ea2176d
      Ingo Molnar authored
      Use the lock validator framework to prove rwsem locking correctness.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      4ea2176d
    • Ingo Molnar's avatar
      [PATCH] lockdep: allow read_lock() recursion of same class · 6c9076ec
      Ingo Molnar authored
      From: Ingo Molnar <mingo@elte.hu>
      
      lockdep so far only allowed read-recursion for the same lock instance.
      This is enough in the overwhelming majority of cases, but a hostap case
      triggered and reported by Miles Lane relies on same-class
      different-instance recursion.  So we relax the restriction on read-lock
      recursion.
      
      (This change does not allow rwsem read-recursion, which is still
      forbidden.)
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      6c9076ec
    • Ingo Molnar's avatar
      [PATCH] lockdep: core · fbb9ce95
      Ingo Molnar authored
      Do 'make oldconfig' and accept all the defaults for new config options -
      reboot into the kernel and if everything goes well it should boot up fine and
      you should have /proc/lockdep and /proc/lockdep_stats files.
      
      Typically if the lock validator finds some problem it will print out
      voluminous debug output that begins with "BUG: ..." and which syslog output
      can be used by kernel developers to figure out the precise locking scenario.
      
      What does the lock validator do?  It "observes" and maps all locking rules as
      they occur dynamically (as triggered by the kernel's natural use of spinlocks,
      rwlocks, mutexes and rwsems).  Whenever the lock validator subsystem detects a
      new locking scenario, it validates this new rule against the existing set of
      rules.  If this new rule is consistent with the existing set of rules then the
      new rule is added transparently and the kernel continues as normal.  If the
      new rule could create a deadlock scenario then this condition is printed out.
      
      When determining validity of locking, all possible "deadlock scenarios" are
      considered: assuming arbitrary number of CPUs, arbitrary irq context and task
      context constellations, running arbitrary combinations of all the existing
      locking scenarios.  In a typical system this means millions of separate
      scenarios.  This is why we call it a "locking correctness" validator - for all
      rules that are observed the lock validator proves it with mathematical
      certainty that a deadlock could not occur (assuming that the lock validator
      implementation itself is correct and its internal data structures are not
      corrupted by some other kernel subsystem).  [see more details and conditionals
      of this statement in include/linux/lockdep.h and
      Documentation/lockdep-design.txt]
      
      Furthermore, this "all possible scenarios" property of the validator also
      enables the finding of complex, highly unlikely multi-CPU multi-context races
      via single single-context rules, increasing the likelyhood of finding bugs
      drastically.  In practical terms: the lock validator already found a bug in
      the upstream kernel that could only occur on systems with 3 or more CPUs, and
      which needed 3 very unlikely code sequences to occur at once on the 3 CPUs.
      That bug was found and reported on a single-CPU system (!).  So in essence a
      race will be found "piecemail-wise", triggering all the necessary components
      for the race, without having to reproduce the race scenario itself!  In its
      short existence the lock validator found and reported many bugs before they
      actually caused a real deadlock.
      
      To further increase the efficiency of the validator, the mapping is not per
      "lock instance", but per "lock-class".  For example, all struct inode objects
      in the kernel have inode->inotify_mutex.  If there are 10,000 inodes cached,
      then there are 10,000 lock objects.  But ->inotify_mutex is a single "lock
      type", and all locking activities that occur against ->inotify_mutex are
      "unified" into this single lock-class.  The advantage of the lock-class
      approach is that all historical ->inotify_mutex uses are mapped into a single
      (and as narrow as possible) set of locking rules - regardless of how many
      different tasks or inode structures it took to build this set of rules.  The
      set of rules persist during the lifetime of the kernel.
      
      To see the rough magnitude of checking that the lock validator does, here's a
      portion of /proc/lockdep_stats, fresh after bootup:
      
       lock-classes:                            694 [max: 2048]
       direct dependencies:                  1598 [max: 8192]
       indirect dependencies:               17896
       all direct dependencies:             16206
       dependency chains:                    1910 [max: 8192]
       in-hardirq chains:                      17
       in-softirq chains:                     105
       in-process chains:                    1065
       stack-trace entries:                 38761 [max: 131072]
       combined max dependencies:         2033928
       hardirq-safe locks:                     24
       hardirq-unsafe locks:                  176
       softirq-safe locks:                     53
       softirq-unsafe locks:                  137
       irq-safe locks:                         59
       irq-unsafe locks:                      176
      
      The lock validator has observed 1598 actual single-thread locking patterns,
      and has validated all possible 2033928 distinct locking scenarios.
      
      More details about the design of the lock validator can be found in
      Documentation/lockdep-design.txt, which can also found at:
      
         http://redhat.com/~mingo/lockdep-patches/lockdep-design.txt
      
      [bunk@stusta.de: cleanups]
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarAdrian Bunk <bunk@stusta.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      fbb9ce95
    • Ingo Molnar's avatar
      [PATCH] lockdep: locking API self tests · cae2ed9a
      Ingo Molnar authored
      Introduce DEBUG_LOCKING_API_SELFTESTS, which uses the generic lock debugging
      code's silent-failure feature to run a matrix of testcases.  There are 210
      testcases currently:
      
        +-----------------------
        | Locking API testsuite:
        +------------------------------+------+------+------+------+------+------+
                                       | spin |wlock |rlock |mutex | wsem | rsem |
        -------------------------------+------+------+------+------+------+------+
                           A-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                       A-B-B-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                   A-B-B-C-C-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                   A-B-C-A-B-C deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
               A-B-B-C-C-D-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
               A-B-C-D-B-D-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
               A-B-C-D-B-C-D-A deadlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                          double unlock:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
                       bad unlock order:  ok  |  ok  |  ok  |  ok  |  ok  |  ok  |
        --------------------------------------+------+------+------+------+------+
                    recursive read-lock:             |  ok  |             |  ok  |
        --------------------------------------+------+------+------+------+------+
                      non-nested unlock:  ok  |  ok  |  ok  |  ok  |
        --------------------------------------+------+------+------+
           hard-irqs-on + irq-safe-A/12:  ok  |  ok  |  ok  |
           soft-irqs-on + irq-safe-A/12:  ok  |  ok  |  ok  |
           hard-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
           soft-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
             sirq-safe-A => hirqs-on/12:  ok  |  ok  |  ok  |
             sirq-safe-A => hirqs-on/21:  ok  |  ok  |  ok  |
               hard-safe-A + irqs-on/12:  ok  |  ok  |  ok  |
               soft-safe-A + irqs-on/12:  ok  |  ok  |  ok  |
               hard-safe-A + irqs-on/21:  ok  |  ok  |  ok  |
               soft-safe-A + irqs-on/21:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #1/132:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #1/132:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #1/213:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #1/213:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #1/231:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #1/231:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #1/312:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #1/312:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #1/321:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #1/321:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #2/123:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #2/123:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #2/132:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #2/132:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #2/213:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #2/213:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #2/231:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #2/231:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #2/312:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #2/312:  ok  |  ok  |  ok  |
          hard-safe-A + unsafe-B #2/321:  ok  |  ok  |  ok  |
          soft-safe-A + unsafe-B #2/321:  ok  |  ok  |  ok  |
            hard-irq lock-inversion/123:  ok  |  ok  |  ok  |
            soft-irq lock-inversion/123:  ok  |  ok  |  ok  |
            hard-irq lock-inversion/132:  ok  |  ok  |  ok  |
            soft-irq lock-inversion/132:  ok  |  ok  |  ok  |
            hard-irq lock-inversion/213:  ok  |  ok  |  ok  |
            soft-irq lock-inversion/213:  ok  |  ok  |  ok  |
            hard-irq lock-inversion/231:  ok  |  ok  |  ok  |
            soft-irq lock-inversion/231:  ok  |  ok  |  ok  |
            hard-irq lock-inversion/312:  ok  |  ok  |  ok  |
            soft-irq lock-inversion/312:  ok  |  ok  |  ok  |
            hard-irq lock-inversion/321:  ok  |  ok  |  ok  |
            soft-irq lock-inversion/321:  ok  |  ok  |  ok  |
            hard-irq read-recursion/123:  ok  |
            soft-irq read-recursion/123:  ok  |
            hard-irq read-recursion/132:  ok  |
            soft-irq read-recursion/132:  ok  |
            hard-irq read-recursion/213:  ok  |
            soft-irq read-recursion/213:  ok  |
            hard-irq read-recursion/231:  ok  |
            soft-irq read-recursion/231:  ok  |
            hard-irq read-recursion/312:  ok  |
            soft-irq read-recursion/312:  ok  |
            hard-irq read-recursion/321:  ok  |
            soft-irq read-recursion/321:  ok  |
        --------------------------------+-----+----------------
        Good, all 210 testcases passed! |
        --------------------------------+
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      cae2ed9a
    • Heiko Carstens's avatar
      [PATCH] lockdep: s390 CONFIG_FRAME_POINTER support · cbbd1fa7
      Heiko Carstens authored
      CONFIG_FRAME_POINTER support for s390.
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Acked-by: default avatarIngo Molnar <mingo@elte.hu>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Arjan van de Ven <arjan@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      cbbd1fa7
    • Ingo Molnar's avatar
      [PATCH] lockdep: stacktrace subsystem, core · 8637c099
      Ingo Molnar authored
      Framework to generate and save stacktraces quickly, without printing anything
      to the console.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      8637c099
    • Ingo Molnar's avatar
      [PATCH] lockdep: better lock debugging · 9a11b49a
      Ingo Molnar authored
      Generic lock debugging:
      
       - generalized lock debugging framework. For example, a bug in one lock
         subsystem turns off debugging in all lock subsystems.
      
       - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
         the mutex/rtmutex debugging code: it caused way too much prototype
         hackery, and lockdep will give the same information anyway.
      
       - ability to do silent tests
      
       - check lock freeing in vfree too.
      
       - more finegrained debugging options, to allow distributions to
         turn off more expensive debugging features.
      
      There's no separate 'held mutexes' list anymore - but there's a 'held locks'
      stack within lockdep, which unifies deadlock detection across all lock
      classes.  (this is independent of the lockdep validation stuff - lockdep first
      checks whether we are holding a lock already)
      
      Here are the current debugging options:
      
      CONFIG_DEBUG_MUTEXES=y
      CONFIG_DEBUG_LOCK_ALLOC=y
      
      which do:
      
       config DEBUG_MUTEXES
                bool "Mutex debugging, basic checks"
      
       config DEBUG_LOCK_ALLOC
               bool "Detect incorrect freeing of live mutexes"
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      9a11b49a
    • Ingo Molnar's avatar
      [PATCH] lockdep: remove mutex deadlock checking code · fb7e4241
      Ingo Molnar authored
      With the lock validator we detect mutex deadlocks (and more), the mutex
      deadlock checking code is both redundant and slower.  So remove it.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      fb7e4241
    • Ingo Molnar's avatar
      [PATCH] lockdep: clean up rwsems · c4e05116
      Ingo Molnar authored
      Clean up rwsems.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      c4e05116
  3. 30 Jun, 2006 1 commit
  4. 28 Jun, 2006 2 commits
  5. 27 Jun, 2006 5 commits
  6. 26 Jun, 2006 7 commits
  7. 25 Jun, 2006 8 commits
  8. 23 Jun, 2006 4 commits