Maverick on Hyper-V causes BUG: scheduling while atomic
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
Maverick |
Fix Released
|
Undecided
|
Tim Gardner |
Bug Description
Binary package hint: linux-generic
If a user wants to run Linux in a Hyper-V virtual machine (Hyper-V is Microsoft's virtualization solution, included in Windows Server 2008 and higher), Microsoft provides a set of drivers that enable the use of the high-performance synthetic devices (the equivalent of Xen's PV drivers). Maverick includes some of our drivers by default - hv_vmbus, hv_netvsc, and hv_utils. However, that version of the kernel has an bug in the hv_netvsc driver that results in multiple issues - specifically, you'll see a number of errors in /var/log/messages referring to schedule while atomic. The issue's been fixed upstream as part of the cleanup we've been doing to exit staging, and we have created a patch against Maverick that fixes it.
[ 807.276091] BUG: scheduling while atomic: swapper/
[ 807.277476] Modules linked in: parport_pc ppdev binfmt_misc hv_utils(C) hv_netvsc(C) psmouse lp serio_raw hv_vmbus(C) i2c_piix4 parport floppy tulip [ 807.294414] Modules linked in: parport_pc ppdev binfmt_misc hv_utils(C) hv_netvsc(C) psmouse lp serio_raw hv_vmbus(C) i2c_piix4 parport floppy tulip [ 807.336663]
[ 807.337981] Pid: 0, comm: swapper Tainted: G D C 2.6.35-22-generic #33-Ubuntu Virtual Machine/Virtual Machine
[ 807.339352] EIP: 0060:[<c012c21a>] EFLAGS: 00000246 CPU: 0
[ 807.340699] EIP is at native_
affects: | linux-meta (Ubuntu) → linux (Ubuntu) |
Changed in linux (Ubuntu): | |
assignee: | nobody → Tim Gardner (timg-tpi) |
status: | New → In Progress |
status: | In Progress → Invalid |
assignee: | Tim Gardner (timg-tpi) → nobody |
Changed in linux (Ubuntu Maverick): | |
assignee: | nobody → Tim Gardner (timg-tpi) |
status: | New → In Progress |
tags: | added: verification-needed |
tags: |
added: verification-done removed: verification-needed |
SRU Justification
Impact: The Microsoft hv driver in staging exhibits a variety of faults under load.
Patch description: Use sync_set_bit() and GFP_ATOMIC in key places. Also fix an erroneous WARN_ON.