1. 21 10月, 2011 11 次提交
  2. 19 10月, 2011 3 次提交
  3. 15 10月, 2011 2 次提交
  4. 11 10月, 2011 2 次提交
    • J
      iommu/amd: Fix wrong shift direction · fcd0861d
      Joerg Roedel 提交于
      The shift direction was wrong because the function takes a
      page number and i is the address is the loop.
      
      Cc: stable@kernel.org
      Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
      fcd0861d
    • R
      intel-iommu: Fix AB-BA lockdep report · 3e7abe25
      Roland Dreier 提交于
      When unbinding a device so that I could pass it through to a KVM VM, I
      got the lockdep report below.  It looks like a legitimate lock
      ordering problem:
      
       - domain_context_mapping_one() takes iommu->lock and calls
         iommu_support_dev_iotlb(), which takes device_domain_lock (inside
         iommu->lock).
      
       - domain_remove_one_dev_info() starts by taking device_domain_lock
         then takes iommu->lock inside it (near the end of the function).
      
      So this is the classic AB-BA deadlock.  It looks like a safe fix is to
      simply release device_domain_lock a bit earlier, since as far as I can
      tell, it doesn't protect any of the stuff accessed at the end of
      domain_remove_one_dev_info() anyway.
      
      BTW, the use of device_domain_lock looks a bit unsafe to me... it's
      at least not obvious to me why we aren't vulnerable to the race below:
      
        iommu_support_dev_iotlb()
                                                domain_remove_dev_info()
      
        lock device_domain_lock
          find info
        unlock device_domain_lock
      
                                                lock device_domain_lock
                                                  find same info
                                                unlock device_domain_lock
      
                                                free_devinfo_mem(info)
      
        do stuff with info after it's free
      
      However I don't understand the locking here well enough to know if
      this is a real problem, let alone what the best fix is.
      
      Anyway here's the full lockdep output that prompted all of this:
      
           =======================================================
           [ INFO: possible circular locking dependency detected ]
           2.6.39.1+ #1
           -------------------------------------------------------
           bash/13954 is trying to acquire lock:
            (&(&iommu->lock)->rlock){......}, at: [<ffffffff812f6421>] domain_remove_one_dev_info+0x121/0x230
      
           but task is already holding lock:
            (device_domain_lock){-.-...}, at: [<ffffffff812f6508>] domain_remove_one_dev_info+0x208/0x230
      
           which lock already depends on the new lock.
      
           the existing dependency chain (in reverse order) is:
      
           -> #1 (device_domain_lock){-.-...}:
                  [<ffffffff8109ca9d>] lock_acquire+0x9d/0x130
                  [<ffffffff81571475>] _raw_spin_lock_irqsave+0x55/0xa0
                  [<ffffffff812f8350>] domain_context_mapping_one+0x600/0x750
                  [<ffffffff812f84df>] domain_context_mapping+0x3f/0x120
                  [<ffffffff812f9175>] iommu_prepare_identity_map+0x1c5/0x1e0
                  [<ffffffff81ccf1ca>] intel_iommu_init+0x88e/0xb5e
                  [<ffffffff81cab204>] pci_iommu_init+0x16/0x41
                  [<ffffffff81002165>] do_one_initcall+0x45/0x190
                  [<ffffffff81ca3d3f>] kernel_init+0xe3/0x168
                  [<ffffffff8157ac24>] kernel_thread_helper+0x4/0x10
      
           -> #0 (&(&iommu->lock)->rlock){......}:
                  [<ffffffff8109bf3e>] __lock_acquire+0x195e/0x1e10
                  [<ffffffff8109ca9d>] lock_acquire+0x9d/0x130
                  [<ffffffff81571475>] _raw_spin_lock_irqsave+0x55/0xa0
                  [<ffffffff812f6421>] domain_remove_one_dev_info+0x121/0x230
                  [<ffffffff812f8b42>] device_notifier+0x72/0x90
                  [<ffffffff8157555c>] notifier_call_chain+0x8c/0xc0
                  [<ffffffff81089768>] __blocking_notifier_call_chain+0x78/0xb0
                  [<ffffffff810897b6>] blocking_notifier_call_chain+0x16/0x20
                  [<ffffffff81373a5c>] __device_release_driver+0xbc/0xe0
                  [<ffffffff81373ccf>] device_release_driver+0x2f/0x50
                  [<ffffffff81372ee3>] driver_unbind+0xa3/0xc0
                  [<ffffffff813724ac>] drv_attr_store+0x2c/0x30
                  [<ffffffff811e4506>] sysfs_write_file+0xe6/0x170
                  [<ffffffff8117569e>] vfs_write+0xce/0x190
                  [<ffffffff811759e4>] sys_write+0x54/0xa0
                  [<ffffffff81579a82>] system_call_fastpath+0x16/0x1b
      
           other info that might help us debug this:
      
           6 locks held by bash/13954:
            #0:  (&buffer->mutex){+.+.+.}, at: [<ffffffff811e4464>] sysfs_write_file+0x44/0x170
            #1:  (s_active#3){++++.+}, at: [<ffffffff811e44ed>] sysfs_write_file+0xcd/0x170
            #2:  (&__lockdep_no_validate__){+.+.+.}, at: [<ffffffff81372edb>] driver_unbind+0x9b/0xc0
            #3:  (&__lockdep_no_validate__){+.+.+.}, at: [<ffffffff81373cc7>] device_release_driver+0x27/0x50
            #4:  (&(&priv->bus_notifier)->rwsem){.+.+.+}, at: [<ffffffff8108974f>] __blocking_notifier_call_chain+0x5f/0xb0
            #5:  (device_domain_lock){-.-...}, at: [<ffffffff812f6508>] domain_remove_one_dev_info+0x208/0x230
      
           stack backtrace:
           Pid: 13954, comm: bash Not tainted 2.6.39.1+ #1
           Call Trace:
            [<ffffffff810993a7>] print_circular_bug+0xf7/0x100
            [<ffffffff8109bf3e>] __lock_acquire+0x195e/0x1e10
            [<ffffffff810972bd>] ? trace_hardirqs_off+0xd/0x10
            [<ffffffff8109d57d>] ? trace_hardirqs_on_caller+0x13d/0x180
            [<ffffffff8109ca9d>] lock_acquire+0x9d/0x130
            [<ffffffff812f6421>] ? domain_remove_one_dev_info+0x121/0x230
            [<ffffffff81571475>] _raw_spin_lock_irqsave+0x55/0xa0
            [<ffffffff812f6421>] ? domain_remove_one_dev_info+0x121/0x230
            [<ffffffff810972bd>] ? trace_hardirqs_off+0xd/0x10
            [<ffffffff812f6421>] domain_remove_one_dev_info+0x121/0x230
            [<ffffffff812f8b42>] device_notifier+0x72/0x90
            [<ffffffff8157555c>] notifier_call_chain+0x8c/0xc0
            [<ffffffff81089768>] __blocking_notifier_call_chain+0x78/0xb0
            [<ffffffff810897b6>] blocking_notifier_call_chain+0x16/0x20
            [<ffffffff81373a5c>] __device_release_driver+0xbc/0xe0
            [<ffffffff81373ccf>] device_release_driver+0x2f/0x50
            [<ffffffff81372ee3>] driver_unbind+0xa3/0xc0
            [<ffffffff813724ac>] drv_attr_store+0x2c/0x30
            [<ffffffff811e4506>] sysfs_write_file+0xe6/0x170
            [<ffffffff8117569e>] vfs_write+0xce/0x190
            [<ffffffff811759e4>] sys_write+0x54/0xa0
            [<ffffffff81579a82>] system_call_fastpath+0x16/0x1b
      Signed-off-by: NRoland Dreier <roland@purestorage.com>
      Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
      3e7abe25
  5. 10 10月, 2011 1 次提交
  6. 30 9月, 2011 1 次提交
  7. 26 9月, 2011 1 次提交
  8. 21 9月, 2011 6 次提交
  9. 14 9月, 2011 4 次提交
  10. 13 9月, 2011 3 次提交
  11. 06 9月, 2011 1 次提交
  12. 05 9月, 2011 5 次提交