Comment 17 for bug 1664663

Joe, I take that back - comment #16 is incorrect.

I'm seeing a call trace kvp related when using a high numbers of cores on the VM on the test kernel provided.
We cannot repro that on 4.10.0-19 and nor in the latest one 4.10.0-26.

Can you please apply that patch on top of current 4.10.0-26 so we can re-test that?
Thank you!

Call trace for reference:

[ 72.265165] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[ 72.265177] IP: hv_begin_read+0xc/0x20 [hv_vmbus]
[ 72.265178] PGD 0
[ 72.265179]
[ 72.265182] Oops: 0002 [#1] SMP
[ 72.265783] Modules linked in: hv_utils(+) hv_storvsc aesni_intel(+) aes_x86_64 ptp hid scsi_transport_fc hv_netvsc c
rypto_simd pps_core hyperv_keyboard glue_helper cryptd psmouse pata_acpi floppy fjes hv_vmbus
[ 72.265798] CPU: 48 PID: 300 Comm: ksoftirqd/48 Not tainted 4.10.0-22-generic #24~lp1664663
[ 72.265800] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012
[ 72.265801] task: ffff91907d620000 task.stack: ffffb78a00e6c000
[ 72.265807] RIP: 0010:hv_begin_read+0xc/0x20 [hv_vmbus]
[ 72.265809] RSP: 0018:ffffb78a00e6fe00 EFLAGS: 00010202
[ 72.265811] RAX: 0000000000000000 RBX: ffff9190764ba000 RCX: 0000000040000084
[ 72.265812] RDX: ffff9190764ba1c0 RSI: 0000000000000000 RDI: ffff9190764ba120
[ 72.265813] RBP: ffffb78a00e6fe00 R08: 0000000000000027 R09: 00000000000193c0
[ 72.265814] R10: 00000000eac0c6e6 R11: 0000000000000010 R12: ffff9190764ba000
[ 72.265815] R13: ffff9190764ba120 R14: ffffffff86005130 R15: 0000000000000006
[ 72.265817] FS: 0000000000000000(0000) GS:ffff91907e200000(0000) knlGS:0000000000000000
[ 72.265818] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 72.265820] CR2: 0000000000000008 CR3: 0000000046a09000 CR4: 00000000001406e0
[ 72.265823] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 72.265824] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 72.265825] Call Trace:
[ 72.265832] vmbus_on_event+0x49/0x70 [hv_vmbus]
[ 72.265840] tasklet_action+0x5e/0x110
[ 72.265847] __do_softirq+0x104/0x2af
[ 72.265850] run_ksoftirqd+0x29/0x60
[ 72.265855] smpboot_thread_fn+0x10a/0x160
[ 72.265860] kthread+0x109/0x140
[ 72.265863] ? sort_range+0x30/0x30
[ 72.265867] ? kthread_create_on_node+0x60/0x60
[ 72.265870] ret_from_fork+0x2c/0x40
[ 72.265871] Code: eb f0 89 c6 48 c7 c7 70 2f 21 c0 e8 7e d0 19 c5 eb d8 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 0f 1f
44 00 00 48 8b 07 55 48 89 e5 <c7> 40 08 01 00 00 00 0f ae f0 5d c3 0f 1f 84 00 00 00 00 00 0f
[ 72.265903] RIP: hv_begin_read+0xc/0x20 [hv_vmbus] RSP: ffffb78a00e6fe00
[ 72.265904] CR2: 0000000000000008
[ 72.265922] ---[ end trace 896d8fc4b37b0731 ]---
[ 72.265923] Kernel panic - not syncing: Fatal exception in interrupt
[ 72.269147] Kernel Offset: 0x4200000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff
)
[ 72.269147] ---[ end Kernel panic - not syncing: Fatal exception in interrupt