1. 25 Sep, 2010 1 commit
    • Eric Dumazet's avatar
      net: fix a lockdep splat · f064af1e
      Eric Dumazet authored
      We have for each socket :
      
      One spinlock (sk_slock.slock)
      One rwlock (sk_callback_lock)
      
      Possible scenarios are :
      
      (A) (this is used in net/sunrpc/xprtsock.c)
      read_lock(&sk->sk_callback_lock) (without blocking BH)
      <BH>
      spin_lock(&sk->sk_slock.slock);
      ...
      read_lock(&sk->sk_callback_lock);
      ...
      
      (B)
      write_lock_bh(&sk->sk_callback_lock)
      stuff
      write_unlock_bh(&sk->sk_callback_lock)
      
      (C)
      spin_lock_bh(&sk->sk_slock)
      ...
      write_lock_bh(&sk->sk_callback_lock)
      stuff
      write_unlock_bh(&sk->sk_callback_lock)
      spin_unlock_bh(&sk->sk_slock)
      
      This (C) case conflicts with (A) :
      
      CPU1 [A]                         CPU2 [C]
      read_lock(callback_lock)
      <BH>                             spin_lock_bh(slock)
      <wait to spin_lock(slock)>
                                       <wait to write_lock_bh(callback_lock)>
      
      We have one problematic (C) use case in inet_csk_listen_stop() :
      
      local_bh_disable();
      bh_lock_sock(child); // spin_lock_bh(&sk->sk_slock)
      WARN_ON(sock_owned_by_user(child));
      ...
      sock_orphan(child); // write_lock_bh(&sk->sk_callback_lock)
      
      lockdep is not happy with this, as reported by Tetsuo Handa
      
      It seems only way to deal with this is to use read_lock_bh(callbacklock)
      everywhere.
      
      Thanks to Jarek for pointing a bug in my first attempt and suggesting
      this solution.
      Reported-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
      Tested-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      CC: Jarek Poplawski <jarkao2@gmail.com>
      Tested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f064af1e
  2. 23 Sep, 2010 7 commits
  3. 22 Sep, 2010 9 commits
  4. 21 Sep, 2010 4 commits
  5. 20 Sep, 2010 6 commits
  6. 18 Sep, 2010 2 commits
  7. 17 Sep, 2010 9 commits
  8. 16 Sep, 2010 1 commit
  9. 15 Sep, 2010 1 commit
    • Denis Kirjanov's avatar
      3c59x: Remove atomic context inside vortex_{set|get}_wol · 84176b7b
      Denis Kirjanov authored
      There is no need to use spinlocks in vortex_{set|get}_wol.
      This also fixes a bug:
      [  254.214993] 3c59x 0000:00:0d.0: PME# enabled
      [  254.215021] BUG: sleeping function called from invalid context at kernel/mutex.c:94
      [  254.215030] in_atomic(): 0, irqs_disabled(): 1, pid: 4875, name: ethtool
      [  254.215042] Pid: 4875, comm: ethtool Tainted: G        W   2.6.36-rc3+ #7
      [  254.215049] Call Trace:
      [  254.215050]  [] __might_sleep+0xb1/0xb6
      [  254.215050]  [] mutex_lock+0x17/0x30
      [  254.215050]  [] acpi_enable_wakeup_device_power+0x2b/0xb1
      [  254.215050]  [] acpi_pm_device_sleep_wake+0x42/0x7f
      [  254.215050]  [] acpi_pci_sleep_wake+0x5d/0x63
      [  254.215050]  [] platform_pci_sleep_wake+0x1d/0x20
      [  254.215050]  [] __pci_enable_wake+0x90/0xd0
      [  254.215050]  [] acpi_set_WOL+0x8e/0xf5 [3c59x]
      [  254.215050]  [] vortex_set_wol+0x4e/0x5e [3c59x]
      [  254.215050]  [] dev_ethtool+0x1cf/0xb61
      [  254.215050]  [] ? debug_mutex_free_waiter+0x45/0x4a
      [  254.215050]  [] ? __mutex_lock_common+0x204/0x20e
      [  254.215050]  [] ? __mutex_lock_slowpath+0x12/0x15
      [  254.215050]  [] ? mutex_lock+0x23/0x30
      [  254.215050]  [] dev_ioctl+0x42c/0x533
      [  254.215050]  [] ? _cond_resched+0x8/0x1c
      [  254.215050]  [] ? lock_page+0x1c/0x30
      [  254.215050]  [] ? page_address+0x15/0x7c
      [  254.215050]  [] ? filemap_fault+0x187/0x2c4
      [  254.215050]  [] sock_ioctl+0x1d4/0x1e0
      [  254.215050]  [] ? sock_ioctl+0x0/0x1e0
      [  254.215050]  [] vfs_ioctl+0x19/0x33
      [  254.215050]  [] do_vfs_ioctl+0x424/0x46f
      [  254.215050]  [] ? selinux_file_ioctl+0x3c/0x40
      [  254.215050]  [] sys_ioctl+0x40/0x5a
      [  254.215050]  [] sysenter_do_call+0x12/0x22
      
      vortex_set_wol protected with a spinlock, but nested  acpi_set_WOL acquires a mutex inside atomic context.
      Ethtool operations are already serialized by RTNL mutex, so it is safe to drop the locks.
      Signed-off-by: default avatarDenis Kirjanov <dkirjanov@kernel.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      84176b7b