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Re: [PATCH v6] virtio-pci: Fix the crash that the vector was used after
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From: |
Michael S. Tsirkin |
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Subject: |
Re: [PATCH v6] virtio-pci: Fix the crash that the vector was used after released. |
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Date: |
Mon, 15 Apr 2024 05:20:23 -0400 |
On Mon, Apr 15, 2024 at 05:11:05PM +0800, Cindy Lu wrote:
> On Mon, Apr 15, 2024 at 4:32 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Fri, Apr 12, 2024 at 02:26:55PM +0800, Cindy Lu wrote:
> > > During the booting process of the non-standard image, the behavior of the
> > > called function in qemu is as follows:
> > >
> > > 1. vhost_net_stop() was triggered by guest image. This will call the
> > > function
> > > virtio_pci_set_guest_notifiers() with assgin= false,
> > > virtio_pci_set_guest_notifiers(） will release the irqfd for vector 0
> > >
> > > 2. virtio_reset() was triggered, this will set configure vector to
> > > VIRTIO_NO_VECTOR
> > >
> > > 3.vhost_net_start() was called (at this time, the configure vector is
> > > still VIRTIO_NO_VECTOR) and then call virtio_pci_set_guest_notifiers()
> > > with
> > > assgin=true, so the irqfd for vector 0 is still not "init" during this
> > > process
> > >
> > > 4. The system continues to boot and sets the vector back to 0. After that
> > > msix_fire_vector_notifier() was triggered to unmask the vector 0 and
> > > meet the crash
> > >
> > > To fix the issue, we need to support changing the vector after
> > > VIRTIO_CONFIG_S_DRIVER_OK is set.
> > >
> > > (gdb) bt
> > > 0 __pthread_kill_implementation (threadid=<optimized out>,
> > > signo=signo@entry=6, no_tid=no_tid@entry=0)
> > > at pthread_kill.c:44
> > > 1 0x00007fc87148ec53 in __pthread_kill_internal (signo=6,
> > > threadid=<optimized out>) at pthread_kill.c:78
> > > 2 0x00007fc87143e956 in __GI_raise (sig=sig@entry=6) at
> > > ../sysdeps/posix/raise.c:26
> > > 3 0x00007fc8714287f4 in __GI_abort () at abort.c:79
> > > 4 0x00007fc87142871b in __assert_fail_base
> > > (fmt=0x7fc8715bbde0 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
> > > assertion=0x5606413efd53 "ret == 0", file=0x5606413ef87d
> > > "../accel/kvm/kvm-all.c", line=1837, function=<optimized out>) at
> > > assert.c:92
> > > 5 0x00007fc871437536 in __GI___assert_fail
> > > (assertion=0x5606413efd53 "ret == 0", file=0x5606413ef87d
> > > "../accel/kvm/kvm-all.c", line=1837, function=0x5606413f06f0
> > > <__PRETTY_FUNCTION__.19> "kvm_irqchip_commit_routes") at assert.c:101
> > > 6 0x0000560640f884b5 in kvm_irqchip_commit_routes (s=0x560642cae1f0) at
> > > ../accel/kvm/kvm-all.c:1837
> > > 7 0x0000560640c98f8e in virtio_pci_one_vector_unmask
> > > (proxy=0x560643c65f00, queue_no=4294967295, vector=0, msg=...,
> > > n=0x560643c6e4c8)
> > > at ../hw/virtio/virtio-pci.c:1005
> > > 8 0x0000560640c99201 in virtio_pci_vector_unmask (dev=0x560643c65f00,
> > > vector=0, msg=...)
> > > at ../hw/virtio/virtio-pci.c:1070
> > > 9 0x0000560640bc402e in msix_fire_vector_notifier (dev=0x560643c65f00,
> > > vector=0, is_masked=false)
> > > at ../hw/pci/msix.c:120
> > > 10 0x0000560640bc40f1 in msix_handle_mask_update (dev=0x560643c65f00,
> > > vector=0, was_masked=true)
> > > at ../hw/pci/msix.c:140
> > > 11 0x0000560640bc4503 in msix_table_mmio_write (opaque=0x560643c65f00,
> > > addr=12, val=0, size=4)
> > > at ../hw/pci/msix.c:231
> > > 12 0x0000560640f26d83 in memory_region_write_accessor
> > > (mr=0x560643c66540, addr=12, value=0x7fc86b7bc628, size=4, shift=0,
> > > mask=4294967295, attrs=...)
> > > at ../system/memory.c:497
> > > 13 0x0000560640f270a6 in access_with_adjusted_size
> > >
> > > (addr=12, value=0x7fc86b7bc628, size=4, access_size_min=1,
> > > access_size_max=4, access_fn=0x560640f26c8d
> > > <memory_region_write_accessor>, mr=0x560643c66540, attrs=...) at
> > > ../system/memory.c:573
> > > 14 0x0000560640f2a2b5 in memory_region_dispatch_write (mr=0x560643c66540,
> > > addr=12, data=0, op=MO_32, attrs=...)
> > > at ../system/memory.c:1521
> > > 15 0x0000560640f37bac in flatview_write_continue
> > > (fv=0x7fc65805e0b0, addr=4273803276, attrs=..., ptr=0x7fc871e9c028,
> > > len=4, addr1=12, l=4, mr=0x560643c66540)
> > > at ../system/physmem.c:2714
> > > 16 0x0000560640f37d0f in flatview_write
> > > (fv=0x7fc65805e0b0, addr=4273803276, attrs=..., buf=0x7fc871e9c028,
> > > len=4) at ../system/physmem.c:2756
> > > 17 0x0000560640f380bf in address_space_write
> > > (as=0x560642161ae0 <address_space_memory>, addr=4273803276,
> > > attrs=..., buf=0x7fc871e9c028, len=4)
> > > at ../system/physmem.c:2863
> > > 18 0x0000560640f3812c in address_space_rw
> > > (as=0x560642161ae0 <address_space_memory>, addr=4273803276,
> > > attrs=..., buf=0x7fc871e9c028, len=4, is_write=true) at
> > > ../system/physmem.c:2873
> > > --Type <RET> for more, q to quit, c to continue without paging--
> > > 19 0x0000560640f8aa55 in kvm_cpu_exec (cpu=0x560642f205e0) at
> > > ../accel/kvm/kvm-all.c:2915
> > > 20 0x0000560640f8d731 in kvm_vcpu_thread_fn (arg=0x560642f205e0) at
> > > ../accel/kvm/kvm-accel-ops.c:51
> > > 21 0x00005606411949f4 in qemu_thread_start (args=0x560642f292b0) at
> > > ../util/qemu-thread-posix.c:541
> > > 22 0x00007fc87148cdcd in start_thread (arg=<optimized out>) at
> > > pthread_create.c:442
> > > 23 0x00007fc871512630 in clone3 () at
> > > ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
> > > (gdb)
> > >
> > > Fixes: f9a09ca3ea ("vhost: add support for configure interrupt")
> > > Cc: qemu-stable@nongnu.org
> > >
> >
> > empty line not needed here
> >
> will fix this
>
> > > Signed-off-by: Cindy Lu <lulu@redhat.com>
> >
> > Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> >
> > It's guest triggerable so either we merge this before the release,
> > or rely on stable process :(
> >
> thanks a lot for explain this, but I'm still not very clear about this
> do you mean this can not be merged before 2024-04-23?
> https://wiki.qemu.org/Planning/9.0#Release_Schedule
> Really Thanks for your help
> thanks
> cindy
>
> > > ---
> > > hw/virtio/virtio-pci.c | 43 ++++++++++++++++++++++++++++++++++++++++--
> > > 1 file changed, 41 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > > index 1a7039fb0c..f83ec92990 100644
> > > --- a/hw/virtio/virtio-pci.c
> > > +++ b/hw/virtio/virtio-pci.c
> > > @@ -1423,6 +1423,36 @@ static int virtio_pci_add_mem_cap(VirtIOPCIProxy
> > > *proxy,
> > >
> > > return offset;
> > > }
> > > +static void virtio_pci_set_and_change_vector(VirtIODevice *vdev,
> > > + VirtIOPCIProxy *proxy,
> > > + int queue_no, uint16_t
> > > old_vector,
> > > + uint16_t new_vector)
> > > +{
> > > + /*
> > > + * If the device uses irqfd and the vector changes after DRIVER_OK is
> > > + * set, we need to release the old vector and set up the new one.
> > > + * others just need to set the new vector to device
> > > + */
> > > + if ((vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> > > + (msix_enabled(&proxy->pci_dev) && kvm_msi_via_irqfd_enabled())) {
> > > + if (old_vector != VIRTIO_NO_VECTOR) {
> > > + kvm_virtio_pci_vector_release_one(proxy, queue_no);
> > > + }
> > > + }
> > > + /*set the new vector to device*/
> > > + if (queue_no == VIRTIO_CONFIG_IRQ_IDX) {
> > > + vdev->config_vector = new_vector;
> > > + } else {
> > > + virtio_queue_set_vector(vdev, queue_no, new_vector);
> > > + }
> > > + /* if the new vector chanegd need to set it up */
> >
> > typo
> >
> sure will fix this
> thanks
>
> cindy
actually more issues.
I posted v7 pls with most things fixed - pls start with that.
> > > + if ((vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> > > + (msix_enabled(&proxy->pci_dev) && kvm_msi_via_irqfd_enabled())) {
> > > + if (new_vector != VIRTIO_NO_VECTOR) {
> > > + kvm_virtio_pci_vector_use_one(proxy, queue_no);
> > > + }
> > > + }
> > > +}
> > >
> > > int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
> > > uint8_t bar, uint64_t offset, uint64_t length,
> > > @@ -1570,7 +1600,12 @@ static void virtio_pci_common_write(void *opaque,
> > > hwaddr addr,
> > > } else {
> > > val = VIRTIO_NO_VECTOR;
> > > }
> > > - vdev->config_vector = val;
> > > + vector = vdev->config_vector;
> > > + /*check if need to change the vector*/
> > > + if (val != vector) {
> > > + virtio_pci_set_and_change_vector(vdev, proxy,
> > > VIRTIO_CONFIG_IRQ_IDX,
> > > + vector, val);
> > > + }
> > > break;
> > > case VIRTIO_PCI_COMMON_STATUS:
> > > if (!(val & VIRTIO_CONFIG_S_DRIVER_OK)) {
> > > @@ -1610,7 +1645,11 @@ static void virtio_pci_common_write(void *opaque,
> > > hwaddr addr,
> > > } else {
> > > val = VIRTIO_NO_VECTOR;
> > > }
> > > - virtio_queue_set_vector(vdev, vdev->queue_sel, val);
> > > + /*check if need to change the vector*/
> > > + if (val != vector) {
> > > + virtio_pci_set_and_change_vector(vdev, proxy,
> > > vdev->queue_sel,
> > > + vector, val);
> > > + }
> > > break;
> > > case VIRTIO_PCI_COMMON_Q_ENABLE:
> > > if (val == 1) {
> > > --
> > > 2.43.0
> >