1. 14 Feb, 2009 2 commits
    • Nick Piggin's avatar
      lockdep: annotate reclaim context (__GFP_NOFS) · cf40bd16
      Nick Piggin authored
      Here is another version, with the incremental patch rolled up, and
      added reclaim context annotation to kswapd, and allocation tracing
      to slab allocators (which may only ever reach the page allocator
      in rare cases, so it is good to put annotations here too).
      
      Haven't tested this version as such, but it should be getting closer
      to merge worthy ;)
      
      --
      After noticing some code in mm/filemap.c accidentally perform a __GFP_FS
      allocation when it should not have been, I thought it might be a good idea to
      try to catch this kind of thing with lockdep.
      
      I coded up a little idea that seems to work. Unfortunately the system has to
      actually be in __GFP_FS page reclaim, then take the lock, before it will mark
      it. But at least that might still be some orders of magnitude more common
      (and more debuggable) than an actual deadlock condition, so we have some
      improvement I hope (the concept is no less complete than discovery of a lock's
      interrupt contexts).
      
      I guess we could even do the same thing with __GFP_IO (normal reclaim), and
      even GFP_NOIO locks too... but filesystems will have the most locks and fiddly
      code paths, so let's start there and see how it goes.
      
      It *seems* to work. I did a quick test.
      
      =================================
      [ INFO: inconsistent lock state ]
      2.6.28-rc6-00007-ged313489-dirty #26
      ---------------------------------
      inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage.
      modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes:
       (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
      {in-reclaim-W} state was registered at:
        [<ffffffff80267bdb>] __lock_acquire+0x75b/0x1a60
        [<ffffffff80268f71>] lock_acquire+0x91/0xc0
        [<ffffffff8070f0e1>] mutex_lock_nested+0xb1/0x310
        [<ffffffffa002002b>] brd_init+0x2b/0x216 [brd]
        [<ffffffff8020903b>] _stext+0x3b/0x170
        [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
        [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
        [<ffffffffffffffff>] 0xffffffffffffffff
      irq event stamp: 3929
      hardirqs last  enabled at (3929): [<ffffffff8070f2b5>] mutex_lock_nested+0x285/0x310
      hardirqs last disabled at (3928): [<ffffffff8070f089>] mutex_lock_nested+0x59/0x310
      softirqs last  enabled at (3732): [<ffffffff8061f623>] sk_filter+0x83/0xe0
      softirqs last disabled at (3730): [<ffffffff8061f5b6>] sk_filter+0x16/0xe0
      
      other info that might help us debug this:
      1 lock held by modprobe/8526:
       #0:  (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
      
      stack backtrace:
      Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged313489-dirty #26
      Call Trace:
       [<ffffffff80265483>] print_usage_bug+0x193/0x1d0
       [<ffffffff80266530>] mark_lock+0xaf0/0xca0
       [<ffffffff80266735>] mark_held_locks+0x55/0xc0
       [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
       [<ffffffff802667ca>] trace_reclaim_fs+0x2a/0x60
       [<ffffffff80285005>] __alloc_pages_internal+0x475/0x580
       [<ffffffff8070f29e>] ? mutex_lock_nested+0x26e/0x310
       [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
       [<ffffffffa002006a>] brd_init+0x6a/0x216 [brd]
       [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
       [<ffffffff8020903b>] _stext+0x3b/0x170
       [<ffffffff8070f8b9>] ? mutex_unlock+0x9/0x10
       [<ffffffff8070f83d>] ? __mutex_unlock_slowpath+0x10d/0x180
       [<ffffffff802669ec>] ? trace_hardirqs_on_caller+0x12c/0x190
       [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
       [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      cf40bd16
    • Johannes Berg's avatar
      timer: implement lockdep deadlock detection · 6f2b9b9a
      Johannes Berg authored
      This modifies the timer code in a way to allow lockdep to detect
      deadlocks resulting from a lock being taken in the timer function
      as well as around the del_timer_sync() call.
      Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
      6f2b9b9a
  2. 07 Feb, 2009 7 commits
  3. 06 Feb, 2009 22 commits
  4. 05 Feb, 2009 9 commits