• Emil Tantilov's avatar
    PCI: Lock each enable/disable num_vfs operation in sysfs · 5b0948df
    Emil Tantilov authored
    Enabling/disabling SRIOV via sysfs by echo-ing multiple values
    simultaneously:
    
      # echo 63 > /sys/class/net/ethX/device/sriov_numvfs&
      # echo 63 > /sys/class/net/ethX/device/sriov_numvfs
    
      # sleep 5
    
      # echo 0 > /sys/class/net/ethX/device/sriov_numvfs&
      # echo 0 > /sys/class/net/ethX/device/sriov_numvfs
    
    results in the following bug:
    
      kernel BUG at drivers/pci/iov.c:495!
      invalid opcode: 0000 [#1] SMP
      CPU: 1 PID: 8050 Comm: bash Tainted: G   W   4.9.0-rc7-net-next #2092
      RIP: 0010:[<ffffffff813b1647>]
    	    [<ffffffff813b1647>] pci_iov_release+0x57/0x60
    
      Call Trace:
       [<ffffffff81391726>] pci_release_dev+0x26/0x70
       [<ffffffff8155be6e>] device_release+0x3e/0xb0
       [<ffffffff81365ee7>] kobject_cleanup+0x67/0x180
       [<ffffffff81365d9d>] kobject_put+0x2d/0x60
       [<ffffffff8155bc27>] put_device+0x17/0x20
       [<ffffffff8139c08a>] pci_dev_put+0x1a/0x20
       [<ffffffff8139cb6b>] pci_get_dev_by_id+0x5b/0x90
       [<ffffffff8139cca5>] pci_get_subsys+0x35/0x40
       [<ffffffff8139ccc8>] pci_get_device+0x18/0x20
       [<ffffffff8139ccfb>] pci_get_domain_bus_and_slot+0x2b/0x60
       [<ffffffff813b09e7>] pci_iov_remove_virtfn+0x57/0x180
       [<ffffffff813b0b95>] pci_disable_sriov+0x65/0x140
       [<ffffffffa00a1af7>] ixgbe_disable_sriov+0xc7/0x1d0 [ixgbe]
       [<ffffffffa00a1e9d>] ixgbe_pci_sriov_configure+0x3d/0x170 [ixgbe]
       [<ffffffff8139d28c>] sriov_numvfs_store+0xdc/0x130
      ...
      RIP  [<ffffffff813b1647>] pci_iov_release+0x57/0x60
    
    Use the existing mutex lock to protect each enable/disable operation.
    Signed-off-by: default avatarEmil Tantilov <emil.s.tantilov@intel.com>
    Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
    Reviewed-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
    CC: Alexander Duyck <alexander.h.duyck@intel.com>
    5b0948df
iov.c 18.3 KB