On 01/14/2014 09:24 AM, Eric Farman wrote:
In some cases, an unplug can cause events to be dropped, which
leads to an assertion failure when preparing to notify the guest
kernel. This merely accommodates both variations of the "no event"
value that could occur in this codepath.
Signed-off-by: Eric Farman <far...@linux.vnet.ibm.com>
---
hw/scsi/virtio-scsi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 49a9576..f8e3632 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -521,7 +521,8 @@ static void virtio_scsi_push_event(VirtIOSCSI *s,
SCSIDevice *dev,
evt->event = event;
evt->reason = reason;
if (!dev) {
- assert(event == VIRTIO_SCSI_T_NO_EVENT);
+ assert(event == VIRTIO_SCSI_T_NO_EVENT ||
+ event == VIRTIO_SCSI_T_EVENTS_MISSED);
} else {
evt->lun[0] = 1;
evt->lun[1] = dev->id;
Didn't want to stuff this in the commit itself, but I am especially
curious about this patch. While I encountered the assertion failure
with some regularity during my testing, with the patch I have
occasionally encountered a guest kernel oops. I believe this patch ends
up allowing us to get just a little bit farther, but that there is still
code needed. Not sure which failure is better, but also haven't had
much success reproducing/debugging the kernel error.
I'm appending the kernel backtrace below, for reference:
[ 21.341765] Unable to handle kernel pointer dereference at virtual
kernel address 63772d302e302000
[ 21.346892] Oops: 0038 [#1] SMP
[ 21.347112] Modules linked in: virtio_blk virtio_scsi dm_multipath
[ 21.347524] CPU: 0 PID: 4 Comm: kworker/0:0 Not tainted 3.10.0 #1
[ 21.348685] Workqueue: events virtscsi_handle_event [virtio_scsi]
[ 21.348939] task: 000000001ff74848 ti: 000000001ffa0000 task.ti:
000000001ffa0000
Krnl GPRS: 000000001cd47b78 63772d302e302e31 0000000001697000
0000000000000001
[ 21.349910] 0000000000000001 0000000000000000
0000000000000000 0000000001697000
[ 21.350185] 0000000000000000 0000000000000000
00000000018e8000 00000000018e8738
[ 21.350425] 000000001ff26e00 0000000001697000
000000001ffa3d08 000000001ffa3ce0
[ 21.350677] Krnl Code: 00000000004637c8: e3e0f0980024 stg
%r14,152(%r15)
00000000004637ce: e31020000004 lg %r1,0(%r2)
#00000000004637d4: e31010c00004 lg %r1,192(%r1)
>00000000004637da: e3c010000002 ltg %r12,0(%r1)
00000000004637e0: a784000a brc 8,4637f4
00000000004637e4: b904002c lgr %r2,%r12
00000000004637e8: c0e5ffe9e944 brasl %r14,1a0a70
00000000004637ee: ec26000b007c cgij %r2,0,6,463804
[ 21.352029] Call Trace:
[ 21.352122] ([<000000000047316c>] scsi_remove_device+0x40/0x50)
[ 21.352330] [<000003ff8000f6ee>] virtscsi_handle_event+0x1ea/0x230
[virtio_scsi]
[ 21.378453] [<0000000000152364>] process_one_work+0x1a8/0x400
[ 21.382530] [<0000000000152a94>] worker_thread+0x144/0x35c
[ 21.382818] [<000000000015a112>] kthread+0xd2/0xdc
[ 21.383105] [<000000000063504e>] kernel_thread_starter+0x6/0xc
[ 21.383391] [<0000000000635048>] kernel_thread_starter+0x0/0xc
[ 21.383679] Last Breaking-Event-Address:
[ 21.383851] [<000003ff8000e1f4>] 0x3ff8000e1f4
[ 21.384080]
[ 21.384142] ---[ end trace 07fb696109d46d45 ]---
[ 21.386001] Unable to handle kernel pointer dereference at virtual
kernel address fffffffffffff000
[ 21.386433] Oops: 0038 [#2] SMP
[ 21.386648] Modules linked in: virtio_blk virtio_scsi dm_multipath
[ 21.387035] CPU: 0 PID: 4 Comm: kworker/0:0 Tainted: G D 3.10.0 #1
[ 21.387471] task: 000000001ff74848 ti: 000000001ffa0000 task.ti:
000000001ffa0000
[ 21.387793] Krnl PSW : 0404e00180000000 000000000015a6c2
(kthread_data+0x6/0x10)
[ 21.388113] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2
PM:0 EA:3
Krnl GPRS: 000000000000000e 0000000000000000 000000001ff74848
0000000000000000
[ 21.392411] 0000000000006f00 000000000000038c
00000000009db800 00000000009db800
[ 21.392759] 00000000009db800 000000001ff74c10
0000000000915c88 0000000002403800
[ 21.393075] 000000001ff74848 0000000000000000
0000000000153270 000000001ffa38d8
[ 21.393398] Krnl Code: 000000000015a6b8: 07fe bcr 15,%r14
000000000015a6ba: 0707 bcr 0,%r7
#000000000015a6bc: e31023800004 lg %r1,896(%r2)
>000000000015a6c2: e3201fd8ff04 lg %r2,-40(%r1)
000000000015a6c8: 07fe bcr 15,%r14
000000000015a6ca: 0707 bcr 0,%r7
000000000015a6cc: ebeff0880024 stmg %r14,%r15,136(%r15)
000000000015a6d2: a7f13fe0 tmll %r15,16352
[ 21.395048] Call Trace:
[ 21.395153] ([<0000000000915c88>] __per_cpu_offset+0x0/0x200)
[ 21.395419] [<00000000006330ac>] __schedule+0x7a8/0xa94
[ 21.395684] [<0000000000136042>] do_exit+0x69e/0xa90
[ 21.395948] [<00000000001126f8>] die+0x154/0x17c
[ 21.396212] [<000000000011c400>] do_no_context+0xa8/0xe0
[ 21.396475] [<00000000006370e2>] do_asce_exception+0x172/0x18c
[ 21.396738] [<00000000006351ce>] pgm_check_handler+0x17a/0x17e
[ 21.396999] [<00000000004637da>] scsi_device_put+0x2e/0x74
[ 21.397262] ([<000000000047316c>] scsi_remove_device+0x40/0x50)
[ 21.397525] [<000003ff8000f6ee>] virtscsi_handle_event+0x1ea/0x230
[virtio_scsi]
[ 21.400894] [<0000000000152364>] process_one_work+0x1a8/0x400
[ 21.403878] [<0000000000152a94>] worker_thread+0x144/0x35c
[ 21.404350] [<000000000015a112>] kthread+0xd2/0xdc
[ 21.404617] [<000000000063504e>] kernel_thread_starter+0x6/0xc
[ 21.404883] [<0000000000635048>] kernel_thread_starter+0x0/0xc
[ 21.405147] Last Breaking-Event-Address:
[ 21.405306] [<000000000015326a>] wq_worker_sleeping+0x22/0xb0
[ 21.405570]
- Eric Farman
