)]}'
{
  "log": [
    {
      "commit": "50cc670aebf4fc64afaf533fb9fa1c8570f09d74",
      "tree": "ad31034c5f78135979cdb5b4878b764696880a57",
      "parents": [
        "e9d55f9dbcf048a882478b437fa3f87becf8a770"
      ],
      "author": {
        "name": "Ingo Molnar",
        "email": "mingo@elte.hu",
        "time": "Wed Dec 06 20:39:30 2006 -0800"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@woody.osdl.org",
        "time": "Thu Dec 07 08:39:43 2006 -0800"
      },
      "message": "[PATCH] lockdep: more chains\n\nSome have reported a chain-table overflow - double its size.\n\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "9bb25bf36f0d7b06368432e2324dbbc2e98b5e60",
      "tree": "c788a094599f6d1d82bd1263290757d7a6a1d7c7",
      "parents": [
        "a4f5749ba6e3f23ae4a137cee10324830db4d081"
      ],
      "author": {
        "name": "Ingo Molnar",
        "email": "mingo@elte.hu",
        "time": "Tue Sep 12 20:35:50 2006 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@g5.osdl.org",
        "time": "Wed Sep 13 07:32:14 2006 -0700"
      },
      "message": "[PATCH] lockdep: double the number of stack-trace entries\n\nMiles Lane reported the \"BUG: MAX_STACK_TRACE_ENTRIES too low!\" message,\nwhich means that during normal use his system produced enough lockdep\nevents so that the 128-thousand entries stack-trace array got exhausted.\nDouble the size of the array.\n\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\nCc: Miles Lane \u003cmiles.lane@gmail.com\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "fbb9ce9530fd9b66096d5187fa6a115d16d9746c",
      "tree": "1151a55e5d56045bac17b9766e6a4696cff0a26f",
      "parents": [
        "cae2ed9aa573415c6e5de9a09b7ff0d74af793bc"
      ],
      "author": {
        "name": "Ingo Molnar",
        "email": "mingo@elte.hu",
        "time": "Mon Jul 03 00:24:50 2006 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@g5.osdl.org",
        "time": "Mon Jul 03 15:27:03 2006 -0700"
      },
      "message": "[PATCH] lockdep: core\n\nDo \u0027make oldconfig\u0027 and accept all the defaults for new config options -\nreboot into the kernel and if everything goes well it should boot up fine and\nyou should have /proc/lockdep and /proc/lockdep_stats files.\n\nTypically if the lock validator finds some problem it will print out\nvoluminous debug output that begins with \"BUG: ...\" and which syslog output\ncan be used by kernel developers to figure out the precise locking scenario.\n\nWhat does the lock validator do?  It \"observes\" and maps all locking rules as\nthey occur dynamically (as triggered by the kernel\u0027s natural use of spinlocks,\nrwlocks, mutexes and rwsems).  Whenever the lock validator subsystem detects a\nnew locking scenario, it validates this new rule against the existing set of\nrules.  If this new rule is consistent with the existing set of rules then the\nnew rule is added transparently and the kernel continues as normal.  If the\nnew rule could create a deadlock scenario then this condition is printed out.\n\nWhen determining validity of locking, all possible \"deadlock scenarios\" are\nconsidered: assuming arbitrary number of CPUs, arbitrary irq context and task\ncontext constellations, running arbitrary combinations of all the existing\nlocking scenarios.  In a typical system this means millions of separate\nscenarios.  This is why we call it a \"locking correctness\" validator - for all\nrules that are observed the lock validator proves it with mathematical\ncertainty that a deadlock could not occur (assuming that the lock validator\nimplementation itself is correct and its internal data structures are not\ncorrupted by some other kernel subsystem).  [see more details and conditionals\nof this statement in include/linux/lockdep.h and\nDocumentation/lockdep-design.txt]\n\nFurthermore, this \"all possible scenarios\" property of the validator also\nenables the finding of complex, highly unlikely multi-CPU multi-context races\nvia single single-context rules, increasing the likelyhood of finding bugs\ndrastically.  In practical terms: the lock validator already found a bug in\nthe upstream kernel that could only occur on systems with 3 or more CPUs, and\nwhich needed 3 very unlikely code sequences to occur at once on the 3 CPUs.\nThat bug was found and reported on a single-CPU system (!).  So in essence a\nrace will be found \"piecemail-wise\", triggering all the necessary components\nfor the race, without having to reproduce the race scenario itself!  In its\nshort existence the lock validator found and reported many bugs before they\nactually caused a real deadlock.\n\nTo further increase the efficiency of the validator, the mapping is not per\n\"lock instance\", but per \"lock-class\".  For example, all struct inode objects\nin the kernel have inode-\u003einotify_mutex.  If there are 10,000 inodes cached,\nthen there are 10,000 lock objects.  But -\u003einotify_mutex is a single \"lock\ntype\", and all locking activities that occur against -\u003einotify_mutex are\n\"unified\" into this single lock-class.  The advantage of the lock-class\napproach is that all historical -\u003einotify_mutex uses are mapped into a single\n(and as narrow as possible) set of locking rules - regardless of how many\ndifferent tasks or inode structures it took to build this set of rules.  The\nset of rules persist during the lifetime of the kernel.\n\nTo see the rough magnitude of checking that the lock validator does, here\u0027s a\nportion of /proc/lockdep_stats, fresh after bootup:\n\n lock-classes:                            694 [max: 2048]\n direct dependencies:                  1598 [max: 8192]\n indirect dependencies:               17896\n all direct dependencies:             16206\n dependency chains:                    1910 [max: 8192]\n in-hardirq chains:                      17\n in-softirq chains:                     105\n in-process chains:                    1065\n stack-trace entries:                 38761 [max: 131072]\n combined max dependencies:         2033928\n hardirq-safe locks:                     24\n hardirq-unsafe locks:                  176\n softirq-safe locks:                     53\n softirq-unsafe locks:                  137\n irq-safe locks:                         59\n irq-unsafe locks:                      176\n\nThe lock validator has observed 1598 actual single-thread locking patterns,\nand has validated all possible 2033928 distinct locking scenarios.\n\nMore details about the design of the lock validator can be found in\nDocumentation/lockdep-design.txt, which can also found at:\n\n   http://redhat.com/~mingo/lockdep-patches/lockdep-design.txt\n\n[bunk@stusta.de: cleanups]\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\nSigned-off-by: Arjan van de Ven \u003carjan@linux.intel.com\u003e\nSigned-off-by: Adrian Bunk \u003cbunk@stusta.de\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    }
  ]
}