On Tue, Sep 30, 2014 at 09:48:02AM +0800, Shannon Zhao wrote: > Hi Christoffer, > > On 2014/9/26 21:44, Christoffer Dall wrote: > > On Fri, Sep 26, 2014 at 12:16:35PM +0200, Christoffer Dall wrote: > >> On Fri, Sep 26, 2014 at 05:26:00PM +0800, Shannon Zhao wrote: > >>> > >>> > >>> On 2014/9/26 16:44, Christoffer Dall wrote: > >>>> Hi Shannon, > >>>> > >>>> On Fri, Sep 26, 2014 at 01:57:46PM +0800, Shannon Zhao wrote: > >>>>> > >>>>> On 2014/9/26 1:49, Christoffer Dall wrote: > >>>>>> The sgi values calculated in read_set_clear_sgi_pend_reg() and > >>>>>> write_set_clear_sgi_pend_reg() were horribly incorrectly multiplied by 4 > >>>>>> with catastrophic results in that subfunctions ended up overwriting > >>>>>> memory not allocated for the expected purpose. > >>>>>> > >>>>>> This showed up as bugs in kfree() and the kernel complaining a lot of > >>>>>> you turn on memory debugging. > >>>>>> > >>>>>> This addresses: http://marc.info/?l=kvm&m=141164910007868&w=2 > >>>>>> > >>>>>> Reported-by: Shannon Zhao <zhaoshenglong@xxxxxxxxxx> > >>>>>> Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> > >>>>>> --- > >>>>>> virt/kvm/arm/vgic.c | 4 ++-- > >>>>>> 1 file changed, 2 insertions(+), 2 deletions(-) > >>>>>> > >>>>>> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c > >>>>>> index b6fab0f..8629678 100644 > >>>>>> --- a/virt/kvm/arm/vgic.c > >>>>>> +++ b/virt/kvm/arm/vgic.c > >>>>>> @@ -816,7 +816,7 @@ static bool read_set_clear_sgi_pend_reg(struct kvm_vcpu *vcpu, > >>>>>> { > >>>>>> struct vgic_dist *dist = &vcpu->kvm->arch.vgic; > >>>>>> int sgi; > >>>>>> - int min_sgi = (offset & ~0x3) * 4; > >>>>>> + int min_sgi = (offset & ~0x3); > >>>>>> int max_sgi = min_sgi + 3; > >>>>>> int vcpu_id = vcpu->vcpu_id; > >>>>>> u32 reg = 0; > >>>>>> @@ -837,7 +837,7 @@ static bool write_set_clear_sgi_pend_reg(struct kvm_vcpu *vcpu, > >>>>>> { > >>>>>> struct vgic_dist *dist = &vcpu->kvm->arch.vgic; > >>>>>> int sgi; > >>>>>> - int min_sgi = (offset & ~0x3) * 4; > >>>>>> + int min_sgi = (offset & ~0x3); > >>>>>> int max_sgi = min_sgi + 3; > >>>>>> int vcpu_id = vcpu->vcpu_id; > >>>>>> u32 reg; > >>>>>> > >>>>> Hi Christoffer, > >>>>> > >>>>> I have test this patch for a few hours. The kfree() bug doesn't appear again. > >>>>> But I come to another problem as followed. > >>>>> The test is that start 2 VMs, sleep 10 and do pkill qemu. > >>>>> > >>>>> qemu-system-aar[1207]: unhandled level 1 permission fault (11) at 0xffffc01ed6c200, esr 0x9200000d > >>>>> pgd = ffffffc012986000 > >>>>> [ffffc01ed6c200] *pgd=0000000000000000, *pud=0000000000000000 > >>>>> > >>>>> CPU: 1 PID: 1207 Comm: qemu-system-aar Not tainted 3.17.0-rc4+ #1 > >>>>> task: ffffffc87b072900 ti: ffffffc0129e0000 task.ti: ffffffc0129e0000 > >>>>> PC is at 0x4181a0 > >>>>> LR is at 0x41826c > >>>>> pc : [<00000000004181a0>] lr : [<000000000041826c>] pstate: 80000000 > >>>>> sp : 0000007fcd38ace0 > >>>>> x29: 0000007fcd38ace0 x28: 0000000000000000 > >>>>> x27: 0000000000000000 x26: 0000000000000000 > >>>>> x25: 0000000000000000 x24: 0000000000000000 > >>>>> x23: 0000000000000000 x22: 0000000000000000 > >>>>> x21: 0000000000000000 x20: 0000000000000000 > >>>>> x19: 0000007fcd38b070 x18: 0000007fcd38ab10 > >>>>> x17: 0000007f9bb14480 x16: 00000000009f2370 > >>>>> x15: ffffffffffffffff x14: 0000000000000000 > >>>>> x13: 0000000000000000 x12: 0000000000000268 > >>>>> x11: 00000000115e5520 x10: 0101010101010101 > >>>>> x9 : 0000000000000004 x8 : 0000000000ac7a78 > >>>>> x7 : 0000000000000000 x6 : 000000000000003f > >>>>> x5 : 0000000000000040 x4 : 0000000000000000 > >>>>> x3 : 0000000000000030 x2 : 0000000000000001 > >>>>> x1 : ffffffc01ed6c200 x0 : ffffffc01ed6c200 > >>>>> > >>>> Hmmm, I just ran a similar loop with a number of tests in the VM for a > >>>> few hours and I didn't see this error. > >>> Yeah, it really need to run longer. > >>> After running about one hour this problem first appears and after running > >>> about 4 hours it second appears. > >>>> > >>>> In any case, this patch should still be merged, but we should try to > >>>> reproduce your setup. > >>> Your patch really solves the kfree() bug. I'll add tested-by line. > >>>> > >>>> What is your command line, exact QEMU version, the file system you use, > >>>> and the guest kernel you are running? > >>> My test script is as followed. QEMU version is v2.1.0 release. > >>> The fs is linaro-image-lamp-genericarmv8-20140727-701.rootfs.tar.gz. > >>> Host kernel is based on marc's branch "kvmtool-vgic-dyn" with your patch > >>> "Fix set_clear_sgi_pend_reg offset". > >>> Guest kernel is 3.16 release. > >>> > >>> while true > >>> do > >>> qemu-system-aarch64 \ > >>> -enable-kvm -smp 4 \ > >>> -kernel Image \ > >>> -m 512 -machine virt,kernel_irqchip=on \ > >>> -initrd guestfs.cpio.gz \ > >>> -cpu host \ > >>> -chardev pty,id=pty0,mux=on -monitor chardev:pty0 \ > >>> -serial chardev:pty0 -daemonize \ > >>> -vnc 0.0.0.0:0 \ > >>> -append "rdinit=/sbin/init console=ttyAMA0 mem=512M root=/dev/ram earlyprintk=pl011,0x9000000 rw" & > >>> > >>> qemu-system-aarch64 \ > >>> -enable-kvm -smp 4 \ > >>> -kernel Image \ > >>> -m 512 -machine virt,kernel_irqchip=on \ > >>> -initrd guestfs.cpio.gz \ > >>> -cpu host \ > >>> -chardev pty,id=pty0,mux=on -monitor chardev:pty0 \ > >>> -serial chardev:pty0 -daemonize \ > >>> -vnc 0.0.0.0:1 \ > >>> -append "rdinit=/sbin/init console=ttyAMA0 mem=512M root=/dev/ram earlyprintk=pl011,0x9000000 rw" & > >>> sleep 5 > >>> pkill qemu > >> > >> ok, I'll try to reproduce. > >> > > With kvmarm/queue as both host and guest and otherwise not using vnc but > > nographic and a serial output, I've now been running this for 5 hours > > straight without any issues. That's 1131 runs (2x number of guests > > booted) and counting without seeing this... > > > I have ran the test with kvmarm/queue as both host and guest using > nographic and a serial output. The problem appears. > My environment info: > kvmarm/queue: > commit f003101732065c7e61a4d5394cfc69b01b0bb157 > arm/arm64: KVM: Fix VTTBR_BADDR_MASK and pgd alloc > qemu: > commit 541bbb07eb197a870661ed702ae1f15c7d46aea6 > Update version for v2.1.0 release > fs: > guest: linaro-image-minimal-genericarmv8-20140727-701.rootfs.tar.gz > host: use above minimal fs and add some libs from linaro-image-lamp-genericarmv8-20140727-701.rootfs.tar.gz > > Once this problem appeared, it appears every time when start a vm. > The problem info is always same: > qemu-system-aar[1207]: unhandled level 1 permission fault (11) at 0xffffc01ed6c200, esr 0x9200000d I can't reproduce on my system I'm afraid. I'm running on APM XGene with a Ubuntu distro and a defconfig of the kernel, using the same versions of the kernel and qemu as you are. Which hardware platform are you using? In any case, this doesn't appear to be a KVM bug if it's user distro dependent. -Christoffer -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
