[PATCH 02/14] cxlflash: Fix crash in cxlflash_restore_luntable()

[Matthew R. Ochs]

> On Nov 15, 2016, at 5:14 PM, Uma Krishnan <ukrishn at linux.vnet.ibm.com> wrote:
> 
> During test, the following crash was observed:
> 
> [34538.981505] Faulting instruction address: 0xd000000007c9c870
> cpu 0x9: Vector: 300 (Data Access) at [c0000007f1e8f590]
>    pc: d000000007c9c870: cxlflash_restore_luntable+0x70/0x1d0 [cxlflash]
>    lr: d000000007c9c84c: cxlflash_restore_luntable+0x4c/0x1d0 [cxlflash]
>    sp: c0000007f1e8f810
>   msr: 9000000100009033
>   dar: c00000171d637438
> dsisr: 40000000
>  current = 0xc0000007f1e43f90
>  paca    = 0xc000000007b25100   softe: 0        irq_happened: 0x01
>    pid   = 493, comm = eehd
> enter ? for help
> [c0000007f1e8f8a0] d000000007c940b0 init_afu+0xd60/0x1200 [cxlflash]
> [c0000007f1e8f9a0] d000000007c945a8 cxlflash_pci_slot_reset+0x58/0xe0 [cxlflash]
> [c0000007f1e8fa20] d00000000715f790 cxl_pci_slot_reset+0x230/0x340 [cxl]
> [c0000007f1e8fae0] c000000000040dd4 eeh_report_reset+0x144/0x180
> [c0000007f1e8fb20] c00000000003f708 eeh_pe_dev_traverse+0x98/0x170
> [c0000007f1e8fbb0] c000000000041618 eeh_handle_normal_event+0x328/0x410
> [c0000007f1e8fc30] c000000000041db8 eeh_handle_event+0x178/0x330
> [c0000007f1e8fce0] c000000000042118 eeh_event_handler+0x1a8/0x1b0
> [c0000007f1e8fd80] c00000000011420c kthread+0xec/0x100
> [c0000007f1e8fe30] c00000000000a47c ret_from_kernel_thread+0x5c/0xe0
> 
> When superpipe mode is disabled for a LUN, the references for the
> local lun are deleted but the LUN is still identified as being present
> in the LUN table. This mismatched state can result in the above crash
> when the LUN table is restored during an error recovery operation.
> 
> To fix this issue, the local LUN information structure is updated to
> reflect the LUN is no longer in the LUN table once all references to
> the LUN are gone.
> 
> Signed-off-by: Uma Krishnan <ukrishn at linux.vnet.ibm.com>

Acked-by: Matthew R. Ochs <mrochs at linux.vnet.ibm.com>