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Kernel Oops Exception in ibmvfc_queuecommand+0x4c

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SUSE Linux Enterprise Server 11 Service Pack 4 (SLES 11 SP4)
SUSE Linux Enterprise Server for SAP Applications Service Pack 4
SUSE Linux Enterprise Server for PPC64


After patching to or migrating to the bigmem kernel (3.0.101-108.88 or above)  seeing a kernel panic while starting up SAP HANA database.
Call Trace:
[c000005234362550] [c0000052343625e0] 0xc0000052343625e0 (unreliable)
[c000005234362600] [d0000000c2b75d0c] .ibmvfc_queuecommand+0x4c/0x80 [ibmvfc]
[c0000052343626a0] [d0000000c2312cd4] .scsi_dispatch_cmd+0x104/0x3d0 [scsi_mod]
[c000005234362740] [d0000000c231d0a4] .scsi_request_fn+0x534/0x5e0 [scsi_mod]
[c00000fffff83cf0] [c000000000061298] .icp_hv_ipi_action+0x58/0xc0
[c00000fffff83d80] [c00000000012cfa8] .handle_irq_event_percpu+0x138/0x3c0
[c00000fffff83e70] [c0000000001308f4] .handle_percpu_irq+0x84/0xd0
[c00000fffff83f00] [c000000000012a90] .__do_irq+0x200/0x270
[c00000fffff83f90] [c00000000002485c] .call_do_irq+0x14/0x24
[c0000018c9c9b9d0] [c000000000012b8c] .do_IRQ+0x8c/0x120
[c0000018c9c9ba70] [c0000000000054c8] hardware_interrupt_entry+0x18/0x1c
--- Exception: 501 at .arch_local_irq_restore+0x58/0x70
    LR = .arch_local_irq_restore+0x48/0x70
[c0000018c9c9bd60] [c000000000070ef4] .pSeries_idle+0x34/0x70 (unreliable)
[c0000018c9c9bdd0] [c000000000019864] .cpu_idle+0x184/0x2f0
[c0000018c9c9be90] [c00000000065b368] .start_secondary+0x3e4/0x524
[c0000018c9c9bf90] [c0000000000083e8] .start_secondary_prolog+0x10/0x14


Increase the ibmvfc.max_requests=1024 (default 100). 
This needs to be larger than the number of vCPU's that are assigned to the VM.
You can add this to the kernel command line options.


The default of 100 is not sufficient with the bigmem kernel with over 100 virtual CPU's assigned to VM. 
Having only 100 in-flight I/Os is too low for such a big system.

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  • Document ID:7023972
  • Creation Date: 25-Jun-2019
  • Modified Date:03-Mar-2020
    • SUSE Linux Enterprise Server

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