* longpeng (longpe...@huawei.com) wrote: > Hi guys, > > We found a qemu core in our testing environment, the assertion > 'assert(bus->irq_count[i] == 0)' in pcibus_reset() was triggered and > the bus->irq_count[i] is '-1'. > > Through analysis, it was happened after VM migration and we think > it was caused by the following sequence: > > *Migration Source* > 1. save bus pci.0 state, including irq_count[x] ( =0 , old ) > 2. save E1000: > e1000_pre_save > e1000_mit_timer > set_interrupt_cause > pci_set_irq --> update pci_dev->irq_state to 1 and > update bus->irq_count[x] to 1 ( new ) > the irq_state sent to dest. > > *Migration Dest* > 1. Receive the irq_count[x] of pci.0 is 0 , but the irq_state of e1000 is 1. > 2. If the e1000 need change irqline , it would call to pci_irq_handler(), > the irq_state maybe change to 0 and bus->irq_count[x] will become > -1 in this situation. > 3. do VM reboot then the assertion will be triggered. > > We also found some guys faced the similar problem: > [1] https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg02525.html > [2] https://bugs.launchpad.net/qemu/+bug/1702621 > > Is there some patches to fix this problem ?
I don't remember any. > Can we save pcibus state after all the pci devs are saved ? Does this problem only happen with e1000? I think so. If it's only e1000 I think we should fix it - I think once the VM is stopped for doing the device migration it shouldn't be raising interrupts. Dave > Thanks, > Longpeng(Mike) -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK