Re: [PATCH] kvm/vfio: Fix potential deadlock on vfio group_lock

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 1/31/23 9:34 AM, Jason Gunthorpe wrote:
On Tue, Jan 31, 2023 at 09:27:54AM -0500, Anthony Krowiak wrote:
I encountered a lockdep splat while running some regression tests today (see
below). I suspected it might be this patch so I reverted it, rebuilt the
kernel and ran the regression tests again; this time, the test ran cleanly.
It looks like this patch may not have fixed the problem for which it was
intended. Here is the relevant dmesg output:
Well, it fixes the deadlock it intended to fix and created another one
:)

It means device drivers cannot obtain the kvm lock from their open
functions in this new model.

Why does ap need to touch kvm->lock? (via get_update_locks_for_kvm)


We need the kvm->lock because we take the vCPUs out of SIE in order to dynamically change values in the APCB.



Maybe you should split that lock and have a dedicated apcb lock?


I don't think that would suffice for taking the vCPUs out of SIE.



Jason



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux