[ 03/60] virtio-scsi: Fix virtqueue affinity setup

Greg Kroah-Hartman
2013-08-13T06:33:35Z

From: Asias He <asias@redhat.com>

commit aa52aeea2725839bdd3dcce394486e9a043065e0 upstream.

vscsi->num_queues counts the number of request virtqueue which does not
include the control and event virtqueue. It is wrong to subtract
VIRTIO_SCSI_VQ_BASE from vscsi->num_queues.

This patch fixes the following panic.

(qemu) device_del scsi0

BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
PGD 0
Oops: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 659 Comm: kworker/0:1 Not tainted 3.11.0-rc2+ #1172
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: kacpi_hotplug _handle_hotplug_event_func
task: ffff88007bee1cc0 ti: ffff88007bfe4000 task.ti: ffff88007bfe4000
RIP: 0010:[<ffffffff8179b29f>] [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
RSP: 0018:ffff88007bfe5a38 EFLAGS: 00010202
RAX: 0000000000000010 RBX: ffff880077fd0d28 RCX: 0000000000000050
RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000000
RBP: ffff88007bfe5a58 R08: ffff880077f6ff00 R09: 0000000000000001
R10: ffffffff8143e673 R11: 0000000000000001 R12: 0000000000000001
R13: ffff880077fd0800 R14: 0000000000000000 R15: ffff88007bf489b0
FS: 0000000000000000(0000) GS:ffff88007ea00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000020 CR3: 0000000079f8b000 CR4: 00000000000006f0
Stack:
ffff880077fd0d28 0000000000000000 ffff880077fd0800 0000000000000008
ffff88007bfe5a78 ffffffff8179b37d ffff88007bccc800 ffff88007bccc800
ffff88007bfe5a98 ffffffff8179b3b6 ffff88007bccc800 ffff880077fd0d28
Call Trace:
[<ffffffff8179b37d>] virtscsi_set_affinity+0x2d/0x40
[<ffffffff8179b3b6>] virtscsi_remove_vqs+0x26/0x50
[<ffffffff8179c7d2>] virtscsi_remove+0x82/0xa0
[<ffffffff814cb6b2>] virtio_dev_remove+0x22/0x70
[<ffffffff8167ca49>] __device_release_driver+0x69/0xd0
[<ffffffff8167cb9d>] device_release_driver+0x2d/0x40
[<ffffffff8167bb96>] bus_remove_device+0x116/0x150
[<ffffffff81679936>] device_del+0x126/0x1e0
[<ffffffff81679a06>] device_unregister+0x16/0x30
[<ffffffff814cb889>] unregister_virtio_device+0x19/0x30
[<ffffffff814cdad6>] virtio_pci_remove+0x36/0x80
[<ffffffff81464ae7>] pci_device_remove+0x37/0x70
[<ffffffff8167ca49>] __device_release_driver+0x69/0xd0
[<ffffffff8167cb9d>] device_release_driver+0x2d/0x40
[<ffffffff8167bb96>] bus_remove_device+0x116/0x150
[<ffffffff81679936>] device_del+0x126/0x1e0
[<ffffffff8145edfc>] pci_stop_bus_device+0x9c/0xb0
[<ffffffff8145f036>] pci_stop_and_remove_bus_device+0x16/0x30
[<ffffffff81474a9e>] acpiphp_disable_slot+0x8e/0x150
[<ffffffff81474f6a>] hotplug_event_func+0xba/0x1a0
[<ffffffff814906c8>] ? acpi_os_release_object+0xe/0x12
[<ffffffff81475911>] _handle_hotplug_event_func+0x31/0x70
[<ffffffff810b5333>] process_one_work+0x183/0x500
[<ffffffff810b66e2>] worker_thread+0x122/0x400
[<ffffffff810b65c0>] ? manage_workers+0x2d0/0x2d0
[<ffffffff810bc5de>] kthread+0xce/0xe0
[<ffffffff810bc510>] ? kthread_freezable_should_stop+0x70/0x70
[<ffffffff81ca045c>] ret_from_fork+0x7c/0xb0
[<ffffffff810bc510>] ? kthread_freezable_should_stop+0x70/0x70
Code: 01 00 00 00 74 59 45 31 e4 83 bb c8 01 00 00 02 74 46 66 2e 0f 1f 84 00 00 00 00 00 49 63 c4 48 c1 e0 04 48 8b bc 0
3 10 02 00 00 <48> 8b 47 20 48 8b 80 d0 01 00 00 48 8b 40 50 48 85 c0 74 07 be
RIP [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
RSP <ffff88007bfe5a38>
CR2: 0000000000000020
---[ end trace 99679331a3775f48 ]---

Signed-off-by: Asias He <asias@redhat.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/virtio_scsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -751,7 +751,7 @@ static void __virtscsi_set_affinity(stru

vscsi->affinity_hint_set = true;
} else {
- for (i = 0; i < vscsi->num_queues - VIRTIO_SCSI_VQ_BASE; i++)
+ for (i = 0; i < vscsi->num_queues; i++)
virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);

vscsi->affinity_hint_set = false;