Re: [Qemu-devel] [Bug 1314857] Re: seg fault in ivshmem when using ioeventfd=on

[Cam Macdonell <cam@cs.ualberta.ca>]

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Hello,

The patch for this later bug has been proposed.   I'm not sure why it's not
merged.

http://patchwork.ozlabs.org/patch/316785/

Cheers,
Cam


On Thu, May 1, 2014 at 10:53 AM, Gene Snider <gene@cvtt.net> wrote:

> When I tried the same thing with git master (latest)  I get a different
> error:
> qemu_chr_fe_claim_no_fail: error chardev "(null)" already used
>
> ** Also affects: qemu-kvm (Ubuntu)
>    Importance: Undecided
>        Status: New
>
> --
> You received this bug notification because you are a member of qemu-
> devel-ml, which is subscribed to QEMU.
> https://bugs.launchpad.net/bugs/1314857
>
> Title:
>   seg fault in ivshmem when using ioeventfd=on
>
> Status in QEMU:
>   New
> Status in “qemu-kvm” package in Ubuntu:
>   New
>
> Bug description:
>   When launching qemu with the ivshmem device and the nahanni guest
>   server there is segmentation fault in the setup_ioeventfds function of
>   ivshmem.c. If the ioeventfd=on flag is set the pci_ivshmem_init will
>   call setup_ioeventfds at line 668. This function relies on the 'peers'
>   member of the server info which is not allocated until line 669.
>
>   To reproduce you will need the nahanni guest server code. The driver
>   code is not needed. You will also need a qcow2 or other bootable image
>   to use for launching qemu. The error occurs before the actual image
>   launch.
>
>   Start the nahanni ivshmem server with a small global memory space (
> although the bug is not allocation specific )
>   ivshmem -m 1 -n 2 -p /tmp/ivshmem_socket
>
>   Next launch qemu with initialization for the ivshmem device.
>   qemu-system-x86_64 -hda test_iso.qcow2 -localtime -boot c -chardev
> socket,path="/tmp/ivshmem_socket",id=ivshmem_socket -device
> ivshmem,chardev=ivshmem_socket,size=1,ioeventfd=on
>
>   If gdb is used the following error is recorded:
>   Program received signal SIGSEGV, Segmentation fault.
>   0x000055555579dd52 in setup_ioeventfds (s=0x555556619580)
>       at /home/genes/work/ubuntu/qemu-kvm-1.0+noroms/hw/ivshmem.c:367
>   367             for (j = 0; j < s->peers[i].nb_eventfds; j++) {
>   (gdb) print s->peers
>   $2 = (Peer *) 0x0
>
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>

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