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Description of problem:
Boot a guest w/ macvtap, and set fd as 1025 (over 1024), qemu hangs, and from top in host, the qemu-kvm process exhaust 100% cpu resource.
when set fd=1024, qemu-kvm does not hang, but qemu process exhaust 100% cpu resource, and guest can not boot up.
when fd < 1024, all are ok.
Version-Release number of selected component (if applicable):
# uname -r
2.6.32-416.el6.x86_64
# rpm -q qemu-kvm
qemu-kvm-0.12.1.2-2.400.el6.x86_64
How reproducible:
100%
Steps to Reproduce:
1. Open a shell and ulimit to 10240
# ulimit -n 10240
2. In the same shell, launch guest w/ macvtap and fd > 1024
# /usr/libexec/qemu-kvm -cpu SandyBridge -m 2G -smp 2,sockets=1,cores=2,threads=1 -enable-kvm -name testovs -rtc base=localtime,clock=host,driftfix=slew -drive file=/home/RHEL-Server-6.4-64-virtio.qcow2,if=none,format=qcow2,werror=stop,rerror=stop,cache=none,media=disk,id=drive-scsi0-disk0 -device virtio-scsi-pci,id=scsi0,addr=0x4 -device scsi-hd,scsi-id=0,lun=0,bus=scsi0.0,drive=drive-scsi0-disk0,id=virtio-disk0,bootindex=1 -nodefaults -nodefconfig -monitor stdio -netdev tap,id=macvtap_netdev,fd=1025 -device virtio-net-pci,netdev=macvtap_netdev,mac=92:65:21:bf:09:3c 1025<>/dev/tap9 -vnc :20 -vga std -boot menu=on
3.
Actual results:
Guest start booting, and in shot time, qemu and guest hangs.
Expected results:
No hang and error.
Additional info:
A big (24 patches + tests) and sensitive fix. (pulls in all the async I/O that is used by storage/networking ...)
Needs a lot of QA, so we have to push it to 6.7, and maybe a Z-stream.
Reproduced with qemu-kvm-0.12.1.2-2.458.el6.x86_64.
Steps:
1. set limit of open files to 10240
2. set macvtap up
3. start a qemu-kvm instance with fd > 1024
Actual Result:
(qemu) qemu-kvm: /builddir/build/BUILD/qemu-kvm-0.12.1.2/vl.c:4042: main_loop_wait: Assertion `ioh->fd < 1024' failed.
Program received signal SIGABRT, Aborted.
0x00007ffff4a5e625 in raise () from /lib64/libc.so.6
(gdb) bt
#0 0x00007ffff4a5e625 in raise () from /lib64/libc.so.6
#1 0x00007ffff4a5fe05 in abort () from /lib64/libc.so.6
#2 0x00007ffff4a5774e in __assert_fail_base () from /lib64/libc.so.6
#3 0x00007ffff4a57810 in __assert_fail () from /lib64/libc.so.6
#4 0x00007ffff7db2cd6 in main_loop_wait (timeout=1000) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4042
#5 0x00007ffff7dd622a in kvm_main_loop () at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:2258
#6 0x00007ffff7db74a7 in main_loop (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>)
at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4285
#7 main (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>)
at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:6742
Verified pass with qemu-kvm-0.12.1.2-2.462.el6.x86_64. Neither crash nor hang happened. Guest owned an available IP.
CLI:
/usr/libexec/qemu-kvm -name sriov-test -S -M rhel6.6.0 ... -netdev tap,id=hostnet0,vhost=on,fd=1025 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=b2:8b:46:58:ab:f1,bus=pci.0,addr=0x3 1025<>/dev/tap11
As per above, this issue has fixed correctly.
Moving to VERIFIED.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://rhn.redhat.com/errata/RHBA-2015-1275.html