• Guilherme G. Piccoli's avatar
    cxgb4: fix BUG() on interrupt deallocating path of ULD · 6a146f3a
    Guilherme G. Piccoli authored
    Since the introduction of ULD (Upper-Layer Drivers), the MSI-X
    deallocating path changed in cxgb4: the driver frees the interrupts
    of ULD when unregistering it or on shutdown PCI handler.
    
    Problem is that if a MSI-X is not freed before deallocated in the PCI
    layer, it will trigger a BUG() due to still "alive" interrupt being
    tentatively quiesced.
    
    The below trace was observed when doing a simple unbind of Chelsio's
    adapter PCI function, like:
      "echo 001e:80:00.4 > /sys/bus/pci/drivers/cxgb4/unbind"
    
    Trace:
    
      kernel BUG at drivers/pci/msi.c:352!
      Oops: Exception in kernel mode, sig: 5 [#1]
      ...
      NIP [c0000000005a5e60] free_msi_irqs+0xa0/0x250
      LR [c0000000005a5e50] free_msi_irqs+0x90/0x250
      Call Trace:
      [c0000000005a5e50] free_msi_irqs+0x90/0x250 (unreliable)
      [c0000000005a72c4] pci_disable_msix+0x124/0x180
      [d000000011e06708] disable_msi+0x88/0xb0 [cxgb4]
      [d000000011e06948] free_some_resources+0xa8/0x160 [cxgb4]
      [d000000011e06d60] remove_one+0x170/0x3c0 [cxgb4]
      [c00000000058a910] pci_device_remove+0x70/0x110
      [c00000000064ef04] device_release_driver_internal+0x1f4/0x2c0
      ...
    
    This patch fixes the issue by refactoring the shutdown path of ULD on
    cxgb4 driver, by properly freeing and disabling interrupts on PCI
    remove handler too.
    
    Fixes: 0fbc81b3 ("Allocate resources dynamically for all cxgb4 ULD's")
    Reported-by: default avatarHarsha Thyagaraja <hathyaga@in.ibm.com>
    Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    6a146f3a
cxgb4_main.c 145 KB