* Re: suspicious RCU usage with kvm_pr [not found] <CAOJe8K3mu6M48wGAMMQNXPDrkzk+z4j5yzcJ7eRfex0FWcZsQA@mail.gmail.com> @ 2015-09-16 10:16 ` Thomas Huth 2015-09-16 10:59 ` Denis Kirjanov 0 siblings, 1 reply; 4+ messages in thread From: Thomas Huth @ 2015-09-16 10:16 UTC (permalink / raw) To: Denis Kirjanov, kvm-ppc; +Cc: linuxppc-dev, kvm On 16/09/15 10:51, Denis Kirjanov wrote: > Hi, > > I see the following trace on qemu startup (ps700 blade): > > v4.2-11169-g64d1def > > > [ 143.369638] =============================== > [ 143.369640] [ INFO: suspicious RCU usage. ] > [ 143.369643] 4.2.0-11169-g64d1def #10 Tainted: G S > [ 143.369645] ------------------------------- > [ 143.369647] arch/powerpc/kvm/../../../virt/kvm/kvm_main.c:3310 > suspicious rcu_dereference_check() usage! > [ 143.369649] > other info that might help us debug this: > > [ 143.369652] > rcu_scheduler_active = 1, debug_locks = 1 > [ 143.369655] 1 lock held by qemu-system-ppc/2292: > [ 143.369656] #0: (&vcpu->mutex){+.+.+.}, at: [<d000000004225bac>] > .vcpu_load+0x2c/0xb0 [kvm] > [ 143.369672] > stack backtrace: > [ 143.369675] CPU: 12 PID: 2292 Comm: qemu-system-ppc Tainted: G S > 4.2.0-11169-g64d1def #10 > [ 143.369677] Call Trace: > [ 143.369682] [c0000001d08bf200] [c000000000816dd0] > .dump_stack+0x98/0xd4 (unreliable) > [ 143.369687] [c0000001d08bf280] [c0000000000f7058] > .lockdep_rcu_suspicious+0x108/0x170 > [ 143.369696] [c0000001d08bf310] [d0000000042296d8] > .kvm_io_bus_read+0x1d8/0x220 [kvm] > [ 143.369705] [c0000001d08bf3c0] [d00000000422f980] > .kvmppc_h_logical_ci_load+0x60/0xe0 [kvm] Could it be that we need to srcu_read_lock(&vcpu->kvm->srcu) before calling the kvm_io_bus_read/write() function in the kvmppc_h_logical_ci_load/store() function? Thomas ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: suspicious RCU usage with kvm_pr 2015-09-16 10:16 ` suspicious RCU usage with kvm_pr Thomas Huth @ 2015-09-16 10:59 ` Denis Kirjanov 2015-09-18 13:13 ` Thomas Huth 0 siblings, 1 reply; 4+ messages in thread From: Denis Kirjanov @ 2015-09-16 10:59 UTC (permalink / raw) To: Thomas Huth; +Cc: kvm-ppc, linuxppc-dev, kvm On 9/16/15, Thomas Huth <thuth@redhat.com> wrote: > On 16/09/15 10:51, Denis Kirjanov wrote: >> Hi, >> >> I see the following trace on qemu startup (ps700 blade): >> >> v4.2-11169-g64d1def >> >> >> [ 143.369638] =============================== >> [ 143.369640] [ INFO: suspicious RCU usage. ] >> [ 143.369643] 4.2.0-11169-g64d1def #10 Tainted: G S >> [ 143.369645] ------------------------------- >> [ 143.369647] arch/powerpc/kvm/../../../virt/kvm/kvm_main.c:3310 >> suspicious rcu_dereference_check() usage! >> [ 143.369649] >> other info that might help us debug this: >> >> [ 143.369652] >> rcu_scheduler_active = 1, debug_locks = 1 >> [ 143.369655] 1 lock held by qemu-system-ppc/2292: >> [ 143.369656] #0: (&vcpu->mutex){+.+.+.}, at: [<d000000004225bac>] >> .vcpu_load+0x2c/0xb0 [kvm] >> [ 143.369672] >> stack backtrace: >> [ 143.369675] CPU: 12 PID: 2292 Comm: qemu-system-ppc Tainted: G S >> 4.2.0-11169-g64d1def #10 >> [ 143.369677] Call Trace: >> [ 143.369682] [c0000001d08bf200] [c000000000816dd0] >> .dump_stack+0x98/0xd4 (unreliable) >> [ 143.369687] [c0000001d08bf280] [c0000000000f7058] >> .lockdep_rcu_suspicious+0x108/0x170 >> [ 143.369696] [c0000001d08bf310] [d0000000042296d8] >> .kvm_io_bus_read+0x1d8/0x220 [kvm] >> [ 143.369705] [c0000001d08bf3c0] [d00000000422f980] >> .kvmppc_h_logical_ci_load+0x60/0xe0 [kvm] > > Could it be that we need to srcu_read_lock(&vcpu->kvm->srcu) before > calling the kvm_io_bus_read/write() function in the > kvmppc_h_logical_ci_load/store() function? I haven't had time to dig into this. I'll try it. Thanks > > Thomas > > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: suspicious RCU usage with kvm_pr 2015-09-16 10:59 ` Denis Kirjanov @ 2015-09-18 13:13 ` Thomas Huth 2015-09-18 19:54 ` Denis Kirjanov 0 siblings, 1 reply; 4+ messages in thread From: Thomas Huth @ 2015-09-18 13:13 UTC (permalink / raw) To: Denis Kirjanov; +Cc: kvm-ppc, linuxppc-dev, kvm On 16/09/15 12:59, Denis Kirjanov wrote: > On 9/16/15, Thomas Huth <thuth@redhat.com> wrote: >> On 16/09/15 10:51, Denis Kirjanov wrote: >>> Hi, >>> >>> I see the following trace on qemu startup (ps700 blade): >>> >>> v4.2-11169-g64d1def >>> >>> >>> [ 143.369638] =============================== >>> [ 143.369640] [ INFO: suspicious RCU usage. ] >>> [ 143.369643] 4.2.0-11169-g64d1def #10 Tainted: G S >>> [ 143.369645] ------------------------------- >>> [ 143.369647] arch/powerpc/kvm/../../../virt/kvm/kvm_main.c:3310 >>> suspicious rcu_dereference_check() usage! >>> [ 143.369649] >>> other info that might help us debug this: >>> >>> [ 143.369652] >>> rcu_scheduler_active = 1, debug_locks = 1 >>> [ 143.369655] 1 lock held by qemu-system-ppc/2292: >>> [ 143.369656] #0: (&vcpu->mutex){+.+.+.}, at: [<d000000004225bac>] >>> .vcpu_load+0x2c/0xb0 [kvm] >>> [ 143.369672] >>> stack backtrace: >>> [ 143.369675] CPU: 12 PID: 2292 Comm: qemu-system-ppc Tainted: G S >>> 4.2.0-11169-g64d1def #10 >>> [ 143.369677] Call Trace: >>> [ 143.369682] [c0000001d08bf200] [c000000000816dd0] >>> .dump_stack+0x98/0xd4 (unreliable) >>> [ 143.369687] [c0000001d08bf280] [c0000000000f7058] >>> .lockdep_rcu_suspicious+0x108/0x170 >>> [ 143.369696] [c0000001d08bf310] [d0000000042296d8] >>> .kvm_io_bus_read+0x1d8/0x220 [kvm] >>> [ 143.369705] [c0000001d08bf3c0] [d00000000422f980] >>> .kvmppc_h_logical_ci_load+0x60/0xe0 [kvm] >> >> Could it be that we need to srcu_read_lock(&vcpu->kvm->srcu) before >> calling the kvm_io_bus_read/write() function in the >> kvmppc_h_logical_ci_load/store() function? > > I haven't had time to dig into this. I'll try it. FYI, I had the same problem with kvm_hv, so I tried to come up with a patch: https://patchwork.ozlabs.org/patch/519143/ Sorry, forgot to CC: you there, but it would be great if you could give it a try! Thomas ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: suspicious RCU usage with kvm_pr 2015-09-18 13:13 ` Thomas Huth @ 2015-09-18 19:54 ` Denis Kirjanov 0 siblings, 0 replies; 4+ messages in thread From: Denis Kirjanov @ 2015-09-18 19:54 UTC (permalink / raw) To: Thomas Huth; +Cc: kvm-ppc, linuxppc-dev, kvm On 9/18/15, Thomas Huth <thuth@redhat.com> wrote: > On 16/09/15 12:59, Denis Kirjanov wrote: >> On 9/16/15, Thomas Huth <thuth@redhat.com> wrote: >>> On 16/09/15 10:51, Denis Kirjanov wrote: >>>> Hi, >>>> >>>> I see the following trace on qemu startup (ps700 blade): >>>> >>>> v4.2-11169-g64d1def >>>> >>>> >>>> [ 143.369638] =============================== >>>> [ 143.369640] [ INFO: suspicious RCU usage. ] >>>> [ 143.369643] 4.2.0-11169-g64d1def #10 Tainted: G S >>>> [ 143.369645] ------------------------------- >>>> [ 143.369647] arch/powerpc/kvm/../../../virt/kvm/kvm_main.c:3310 >>>> suspicious rcu_dereference_check() usage! >>>> [ 143.369649] >>>> other info that might help us debug this: >>>> >>>> [ 143.369652] >>>> rcu_scheduler_active = 1, debug_locks = 1 >>>> [ 143.369655] 1 lock held by qemu-system-ppc/2292: >>>> [ 143.369656] #0: (&vcpu->mutex){+.+.+.}, at: [<d000000004225bac>] >>>> .vcpu_load+0x2c/0xb0 [kvm] >>>> [ 143.369672] >>>> stack backtrace: >>>> [ 143.369675] CPU: 12 PID: 2292 Comm: qemu-system-ppc Tainted: G S >>>> 4.2.0-11169-g64d1def #10 >>>> [ 143.369677] Call Trace: >>>> [ 143.369682] [c0000001d08bf200] [c000000000816dd0] >>>> .dump_stack+0x98/0xd4 (unreliable) >>>> [ 143.369687] [c0000001d08bf280] [c0000000000f7058] >>>> .lockdep_rcu_suspicious+0x108/0x170 >>>> [ 143.369696] [c0000001d08bf310] [d0000000042296d8] >>>> .kvm_io_bus_read+0x1d8/0x220 [kvm] >>>> [ 143.369705] [c0000001d08bf3c0] [d00000000422f980] >>>> .kvmppc_h_logical_ci_load+0x60/0xe0 [kvm] >>> >>> Could it be that we need to srcu_read_lock(&vcpu->kvm->srcu) before >>> calling the kvm_io_bus_read/write() function in the >>> kvmppc_h_logical_ci_load/store() function? >> >> I haven't had time to dig into this. I'll try it. > > FYI, I had the same problem with kvm_hv, so I tried to come up with a > patch: > > https://patchwork.ozlabs.org/patch/519143/ > > Sorry, forgot to CC: you there, but it would be great if you could give > it a try! It fixed the issue. Thanks! > > Thomas > > ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-09-18 19:54 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <CAOJe8K3mu6M48wGAMMQNXPDrkzk+z4j5yzcJ7eRfex0FWcZsQA@mail.gmail.com>
2015-09-16 10:16 ` suspicious RCU usage with kvm_pr Thomas Huth
2015-09-16 10:59 ` Denis Kirjanov
2015-09-18 13:13 ` Thomas Huth
2015-09-18 19:54 ` Denis Kirjanov
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).