On Wed, Jul 18, 2012 at 06:23:34PM -0300, Marcelo Tosatti wrote: > On Wed, Jul 18, 2012 at 02:28:34PM -0600, Alex Williamson wrote: > > > turn on lockdep to remember why I couldn't sleep there. > > > > switching to a mutex results in: > > > > BUG: sleeping function called from invalid context at kernel/mutex.c:269 > > in_atomic(): 1, irqs_disabled(): 0, pid: 30025, name: qemu-system-x86 > > INFO: lockdep is turned off. > > Pid: 30025, comm: qemu-system-x86 Not tainted 3.5.0-rc4+ #109 > > Call Trace: > > [<ffffffff81088425>] __might_sleep+0xf5/0x130 > > [<ffffffff81564c6f>] mutex_lock_nested+0x2f/0x60 > > [<ffffffffa07db7d5>] eoifd_event+0x25/0x70 [kvm] > > [<ffffffffa07daea4>] kvm_notify_acked_irq+0xa4/0x140 [kvm] > > [<ffffffffa07dae2a>] ? kvm_notify_acked_irq+0x2a/0x140 [kvm] > > [<ffffffffa07d9bb4>] kvm_ioapic_update_eoi+0x84/0xf0 [kvm] > > [<ffffffffa0806c43>] apic_set_eoi+0x123/0x130 [kvm] > > [<ffffffffa0806fd8>] apic_reg_write+0x388/0x670 [kvm] > > [<ffffffffa07eb03c>] ? vcpu_enter_guest+0x32c/0x740 [kvm] > > [<ffffffffa0807481>] kvm_lapic_set_eoi+0x21/0x30 [kvm] > > [<ffffffffa04ba3f9>] handle_apic_access+0x69/0x80 [kvm_intel] > > [<ffffffffa04ba02a>] vmx_handle_exit+0xaa/0x260 [kvm_intel] > > Its RCU from ack notifiers, OK. I'm testing a patch that moves all bitmap handling to under pic/ioapic lock. After this we can teach kvm_set_irq to report when a bit that is cleared/set is already clear/set, without races. And then no tracking will be necessary in irqfd - we can just call kvm_set_irq(..., 0) and look at the return status. -- MST -- 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
