Re: [Qemu-devel] [PATCH] scsi-cd: Fix crash after remote cdrom detached

[Zheng Xiang]

Hi Paolo,

On 2019/2/15 2:07, Paolo Bonzini wrote:
> On 14/02/19 13:27, Xiang Zheng wrote:
>> There is a small window between the twice blk_is_available in
>> scsi_disk_emulate_command which would cause crash due to the later
>> assertion if the remote cdrom is detached in this window.
>>
>> So this patch replaces assertions with return to avoid qemu crash.
>>
>> Signed-off-by: Xiang Zheng <address@hidden>
>> ---
>> The qemu error log shows:
>>
>> qemu-system-aarch64: /home/qemu/hw/scsi/scsi-disk.c:1896: 
>> scsi_disk_emulate_command: Assertion `blk_is_available(s->qdev.conf.blk)' 
>> failed.
>> 2019-02-15 04:35:18.592: shutting down, reason=crashed
> 
> Is this with virtio-scsi-dataplane?
> 

No, the QEMU commandline about scsi is bellow:
        -device virtio-scsi-pci,id=scsi0,bus=pci.4,addr=0x0 \
        -drive 
file=/mnt/zhengxiang/guestos.qcow2,format=qcow2,if=none,id=drive-scsi0-0-0-0,cache=none,aio=native
 \
        -device 
scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1
 \
        -drive 
file=/home/tmp.iso,format=raw,if=none,id=drive-scsi0-0-0-1,readonly=on,cache=none,aio=threads
 \
        -device 
scsi-cd,bus=scsi0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi0-0-0-1,id=scsi0-0-0-1

This problem can be reproduced by detaching and attaching remote cdrom repeatly.

-- 

Thanks,
Xiang