1. 02 9月, 2020 30 次提交
  2. 21 11月, 2019 5 次提交
  3. 06 11月, 2019 1 次提交
  4. 26 5月, 2019 2 次提交
  5. 06 4月, 2019 1 次提交
    • R
      PCI/PME: Fix hotplug/sysfs remove deadlock in pcie_pme_remove() · 9546c366
      Rafael J. Wysocki 提交于
      [ Upstream commit 95c80bc6952b6a5badc7b702d23e5bf14d251e7c ]
      
      Dongdong reported a deadlock triggered by a hotplug event during a sysfs
      "remove" operation:
      
        pciehp 0000:00:0c.0:pcie004: Slot(0-1): Link Up
        # echo 1 > 0000:00:0c.0/remove
      
        PME and hotplug share an MSI/MSI-X vector.  The sysfs "remove" side is:
      
          remove_store
             pci_stop_and_remove_bus_device_locked
      	 pci_lock_rescan_remove
      	 pci_stop_and_remove_bus_device
      	   ...
      	   pcie_pme_remove
      	     pcie_pme_suspend
      	       synchronize_irq        # wait for hotplug IRQ handler
      	 pci_unlock_rescan_remove
      
        The hotplug side is:
      
          pciehp_ist
             pciehp_handle_presence_or_link_change
      	 pciehp_configure_device
      	   pci_lock_rescan_remove     # wait for pci_unlock_rescan_remove()
      
        INFO: task bash:10913 blocked for more than 120 seconds.
      
        # ps -ax |grep D
         PID TTY      STAT   TIME COMMAND
        10913 ttyAMA0  Ds+    0:00 -bash
        14022 ?        D      0:00 [irq/745-pciehp]
      
        # cat /proc/14022/stack
        __switch_to+0x94/0xd8
        pci_lock_rescan_remove+0x20/0x28
        pciehp_configure_device+0x30/0x140
        pciehp_handle_presence_or_link_change+0x324/0x458
        pciehp_ist+0x1dc/0x1e0
      
        # cat /proc/10913/stack
        __switch_to+0x94/0xd8
        synchronize_irq+0x8c/0xc0
        pcie_pme_suspend+0xa4/0x118
        pcie_pme_remove+0x20/0x40
        pcie_port_remove_service+0x3c/0x58
        ...
        pcie_port_device_remove+0x2c/0x48
        pcie_portdrv_remove+0x68/0x78
        pci_device_remove+0x48/0x120
        ...
        pci_stop_bus_device+0x84/0xc0
        pci_stop_and_remove_bus_device_locked+0x24/0x40
        remove_store+0xa4/0xb8
        dev_attr_store+0x44/0x60
        sysfs_kf_write+0x58/0x80
      
      It is incorrect to call pcie_pme_suspend() from pcie_pme_remove() for two
      reasons.
      
      First, pcie_pme_suspend() calls synchronize_irq(), which will wait for the
      native hotplug interrupt handler as well as for the PME one, because they
      share one IRQ (as per the spec).  That may deadlock if hotplug is signaled
      while pcie_pme_remove() is running and the latter calls
      pci_lock_rescan_remove() before the former.
      
      Second, if pcie_pme_suspend() figures out that wakeup needs to be enabled
      for the port, it will return without disabling the interrupt as expected by
      pcie_pme_remove() which was overlooked by commit c7b5a4e6 ("PCI / PM:
      Fix native PME handling during system suspend/resume").
      
      To fix that, rework pcie_pme_remove() to disable the PME interrupt, clear
      its status and prevent the PME worker function from re-enabling it before
      calling free_irq() on it, which should be sufficient.
      
      Fixes: c7b5a4e6 ("PCI / PM: Fix native PME handling during system suspend/resume")
      Link: https://lore.kernel.org/linux-pci/c7697e7c-e1af-13e4-8491-0a3996e6ab5d@huawei.comReported-by: NDongdong Liu <liudongdong3@huawei.com>
      Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      [bhelgaas: add URL and deadlock details from Dongdong]
      Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      Signed-off-by: NSasha Levin <sashal@kernel.org>
      9546c366
  6. 24 3月, 2019 1 次提交