On Fri, Nov 15, 2013 at 04:35:00PM +0800, Liu Ping Fan wrote: > Since kvmppc_hv_find_lock_hpte() is called from both virtmode and > realmode, so it can trigger the deadlock. > > Suppose the following scene: > > Two physical cpuM, cpuN, two VM instances A, B, each VM has a group of > vcpus. > > If on cpuM, vcpu_A_1 holds bitlock X (HPTE_V_HVLOCK), then is switched > out, and on cpuN, vcpu_A_2 try to lock X in realmode, then cpuN will be > caught in realmode for a long time. > > What makes things even worse if the following happens, > On cpuM, bitlockX is hold, on cpuN, Y is hold. > vcpu_B_2 try to lock Y on cpuM in realmode > vcpu_A_2 try to lock X on cpuN in realmode > > Oops! deadlock happens > > Signed-off-by: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> Reviewed-by: Paul Mackerras <paulus@xxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
