Microsoft Hyper-V Server guest experienced a panic after a function call at storvsc_on_channel_callback+0x249

Issue

• Microsoft Hyper-V Server RHEL6 guest virtual machine crashed after a function call, through a pointer at storvsc_on_channel_callback+0x249

Note: The following is an extract from kernel log buffer, leading up to the crash

    BUG: unable to handle kernel NULL pointer dereference at (null)
    IP: [<(null)>] (null)
    PGD 3beaf067 PUD 3bb14067 PMD 0 
    Oops: 0010 [#1] SMP 
    last sysfs file: /sys/devices/virtual/block/dm-1/range
    CPU 0 
    Modules linked in: ipv6 ext3 jbd sg hv_netvsc(U) hv_utils(U) hid_hyperv(U) microcode hv_timesource(U) i2c_piix4 i2c_core ext4 mbcache jbd2 sd_mod crc_t10dif pata_acpi ata_generic hv_storvsc(U) hv_vmbus(U) dm_mirror dm_region_hash dm_log dm_mod [last unloaded: speedstep_lib]

    Pid: 0, comm: swapper Not tainted 2.6.32-220.el6.x86_64 #1 Microsoft Corporation Virtual Machine/Virtual Machine
    RIP: 0010:[<0000000000000000>]  [<(null)>] (null)
    RSP: 0018:ffff88000b403cd8  EFLAGS: 00010046
    RAX: 0000000000000000 RBX: ffff88003cd9ddc0 RCX: ffff880037f81980
    RDX: ffff880037f81980 RSI: 0000000000000006 RDI: ffff880037f81980
    RBP: ffff88000b403e40 R08: ffff88000b403dc0 R09: 0000000000000001
    R10: 0000000000000000 R11: 0000000000000000 R12: ffff88000b403dd0
    R13: 0000000000000001 R14: 0000000000000030 R15: 0000000000000000
    FS:  0000000000000000(0000) GS:ffff88000b400000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
    CR2: 0000000000000000 CR3: 000000003beae000 CR4: 00000000000006f0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    Process swapper (pid: 0, threadinfo ffffffff81a00000, task ffffffff81a8d020)
    Stack:
     ffffffffa004c58b 0000000000000000 ffff88000b418be0 0000000000000000
    <0> 0000000000000000 ffff88000b403d10 ffffffff8105fa62 ffff880037f82800
    <0> ffffffff81090c06 ffffffff81a00000 ffff880037db4480 ffff88000b403d80
    Call Trace:
     <IRQ> 
     [<ffffffffa004c58b>] ? storvsc_on_channel_callback+0x24b/0x970 [hv_storvsc]
     [<ffffffff8105fa62>] ? default_wake_function+0x12/0x20
     [<ffffffff81090c06>] ? autoremove_wake_function+0x16/0x40
     [<ffffffff81051813>] ? __wake_up+0x53/0x70
     [<ffffffffa003d799>] vmbus_on_event+0xa9/0x110 [hv_vmbus]
     [<ffffffff81072445>] tasklet_action+0xe5/0x120
     [<ffffffff81072161>] __do_softirq+0xc1/0x1d0
     [<ffffffff810d9522>] ? handle_IRQ_event+0x92/0x170
     [<ffffffff8100c24c>] call_softirq+0x1c/0x30
     [<ffffffff8100de85>] do_softirq+0x65/0xa0
     [<ffffffff81071f45>] irq_exit+0x85/0x90
     [<ffffffff814f4d15>] do_IRQ+0x75/0xf0
     [<ffffffff8100ba53>] ret_from_intr+0x0/0x11
     <EOI> 
     [<ffffffff810375ab>] ? native_safe_halt+0xb/0x10
     [<ffffffff810145dd>] default_idle+0x4d/0xb0
     [<ffffffff81009e06>] cpu_idle+0xb6/0x110
     [<ffffffff814d413a>] rest_init+0x7a/0x80
     [<ffffffff81c1ff76>] start_kernel+0x424/0x430
     [<ffffffff81c1f33a>] x86_64_start_reservations+0x125/0x129
     [<ffffffff81c1f438>] x86_64_start_kernel+0xfa/0x109
    Code:  Bad RIP value.
    RIP  [<(null)>] (null)
     RSP <ffff88000b403cd8>
    CR2: 0000000000000000