Created attachment 1081903 [details] tst-strstr.c Description of problem: An old SSE4 strstr from glibc returns incorrect results if running with qemu in accel=tcg mode. Version-Release number of selected component (if applicable): qemu-kvm-2.3.1-3.fc22.x86_64 How reproducible: Always. Steps to Reproduce: 1. Compile the attached self-contained reproducer. 2. Run it with ./tst-strstr Actual results: Output looks like this: error: needle not found at offset 3 (0x4007a3) error: needle not found at offset 4 (0x4007a4) error: needle not found at offset 5 (0x4007a5) … Expected results: No output. Additional info: Test case was extracted from glibc 2.17. Current Fedora no longer has this strstr implementation, but you can test with CentOS 7 in a guest as well. qemu-kvm command line: /usr/bin/qemu-system-x86_64 -machine accel=kvm -name rhel7.0 -S -machine pc-i440fx-2.3,accel=tcg,usb=off -cpu SandyBridge -m 2048 -realtime mlock=off -smp 2,sockets=2,cores=1,threads=1 -uuid b885eb90-c211-4554-bb3e-9406008d8cb5 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/rhel7.0.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x6.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x6 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x6.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x6.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive file=/var/lib/libvirt/images/rhel7.0.qcow2,if=none,id=drive-virtio-disk0,format=qcow2 -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x7,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -netdev tap,fd=23,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:05:91:43,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/channel/target/rhel7.0.org.qemu.guest_agent.0,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 -chardev spicevmc,id=charchannel1,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.redhat.spice.0 -device usb-tablet,id=input0 -spice port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on -device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vgamem_mb=16,bus=pci.0,addr=0x2 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0 -chardev spicevmc,id=charredir1,name=usbredir -device usb-redir,chardev=charredir1,id=redir1 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x8 -msg timestamp=on
Created attachment 1081905 [details] tst-strstr compiled x86_64 program
Can you attach a statically linked binary?
Nevermind, I can reproduce it with the attached binary.
Paolo posted a fix upstream: http://lists.nongnu.org/archive/html/qemu-devel/2015-10/msg02605.html
qemu-2.3.1-8.fc22 has been submitted as an update to Fedora 22. https://bodhi.fedoraproject.org/updates/FEDORA-2015-686f289aa5
qemu-2.3.1-8.fc22 has been pushed to the Fedora 22 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with $ su -c 'dnf --enablerepo=updates-testing update qemu' You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2015-686f289aa5
Update is in stable now