Message-ID: <8028675970aba3f0e412a6a154b907729dda0684.camel@redhat.com>
Date: Wed, 09 Aug 2023 20:14:03 +0200
From: Petr Oros <poros@...hat.com>
To: Przemek Kitszel <przemyslaw.kitszel@...el.com>, netdev@...r.kernel.org
Cc: slawomirx.laba@...el.com, przemyslawx.patynowski@...el.com, 
 kamil.maziarz@...el.com, jesse.brandeburg@...el.com,
 norbertx.zulinski@...el.com,  dawidx.wesierski@...el.com,
 edumazet@...gle.com, anthony.l.nguyen@...el.com, 
 intel-wired-lan@...ts.osuosl.org, kuba@...nel.org, pabeni@...hat.com, 
 davem@...emloft.net, linux-kernel@...r.kernel.org
Subject: Re: [Intel-wired-lan] [PATCH net 2/2] ice: Fix NULL pointer deref
 during VF reset

Przemek Kitszel píše v Čt 01. 01. 1970 v 00:00 +0000:
> On 8/7/23 11:48, Petr Oros wrote:
> > During stress test with attaching and detaching VF from KVM and
> > simultaneously changing VFs spoofcheck and trust there was a
> > NULL pointer dereference in ice_reset_vf that VF's VSI is null.
> > 
> > More than one instance of ice_reset_vf() can be running at a given
> > time. When we rebuild the VSI in ice_reset_vf, another reset can be
> > triaged from ice_service_task. In this case we can access the
> > currently
> > uninitialized VSI and couse panic. The window for this racing
> > condition
> > has been around for a long time but it's much worse after commit
> > 227bf4500aaa ("ice: move VSI delete outside deconfig") because
> > the reset runs faster. ice_reset_vf() using vf->cfg_lock and when
> > we move this lock before accessing to the VF VSI, we can fix
> > BUG for all cases.
> > 
> > Panic occurs sometimes in ice_vsi_is_rx_queue_active() and
> > sometimes
> > in ice_vsi_stop_all_rx_rings()
> > 
> > With our reproducer, we can hint BUG:
> 
> s/hint/hit/
> 
> > ~8h before commit 227bf4500aaa ("ice: move VSI delete outside
> > deconfig").
> > ~20m after commit 227bf4500aaa ("ice: move VSI delete outside
> > deconfig").
> > After this fix we are not able to reproduce it after ~48h
> > 
> > There was commit cf90b74341ee ("ice: Fix call trace with null VSI
> > during
> > VF reset") which also tried to fix this issue, but it was only
> > partially resolved and the bug still exists.
> > 
> > [ 6420.658415] BUG: kernel NULL pointer dereference, address:
> > 0000000000000000
> > [ 6420.665382] #PF: supervisor read access in kernel mode
> > [ 6420.670521] #PF: error_code(0x0000) - not-present page
> > [ 6420.675659] PGD 0
> > [ 6420.677679] Oops: 0000 [#1] PREEMPT SMP NOPTI
> > [ 6420.682038] CPU: 53 PID: 326472 Comm: kworker/53:0 Kdump: loaded
> > Not tainted 5.14.0-317.el9.x86_64 #1
> > [ 6420.691250] Hardware name: Dell Inc. PowerEdge R750/04V528, BIOS
> > 1.6.5 04/15/2022
> > [ 6420.698729] Workqueue: ice ice_service_task [ice]
> > [ 6420.703462] RIP: 0010:ice_vsi_is_rx_queue_active+0x2d/0x60 [ice]
> > [ 6420.705860] ice 0000:ca:00.0: VF 0 is now untrusted
> > [ 6420.709494] Code: 00 00 66 83 bf 76 04 00 00 00 48 8b 77 10 74
> > 3e 31 c0 eb 0f 0f b7 97 76 04 00 00 48 83 c0 01 39 c2 7e 2b 48 8b
> > 97 68 04 00 00 <0f> b7 0c 42 48 8b 96 20 13 00 00 48 8d 94 8a 00 00
> > 12 00 8b 12 83
> > [ 6420.714426] ice 0000:ca:00.0 ens7f0: Setting MAC
> > 22:22:22:22:22:00 on VF 0. VF driver will be reinitialized
> > [ 6420.733120] RSP: 0018:ff778d2ff383fdd8 EFLAGS: 00010246
> > [ 6420.733123] RAX: 0000000000000000 RBX: ff2acf1916294000 RCX:
> > 0000000000000000
> > [ 6420.733125] RDX: 0000000000000000 RSI: ff2acf1f2c6401a0 RDI:
> > ff2acf1a27301828
> > [ 6420.762346] RBP: ff2acf1a27301828 R08: 0000000000000010 R09:
> > 0000000000001000
> > [ 6420.769476] R10: ff2acf1916286000 R11: 00000000019eba3f R12:
> > ff2acf19066460d0
> > [ 6420.776611] R13: ff2acf1f2c6401a0 R14: ff2acf1f2c6401a0 R15:
> > 00000000ffffffff
> > [ 6420.783742] FS:  0000000000000000(0000)
> > GS:ff2acf28ffa80000(0000) knlGS:0000000000000000
> > [ 6420.791829] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 6420.797575] CR2: 0000000000000000 CR3: 00000016ad410003 CR4:
> > 0000000000773ee0
> > [ 6420.804708] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> > 0000000000000000
> > [ 6420.811034] vfio-pci 0000:ca:01.0: enabling device (0000 ->
> > 0002)
> > [ 6420.811840] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> > 0000000000000400
> > [ 6420.811841] PKRU: 55555554
> > [ 6420.811842] Call Trace:
> > [ 6420.811843]  <TASK>
> > [ 6420.811844]  ice_reset_vf+0x9a/0x450 [ice]
> > [ 6420.811876]  ice_process_vflr_event+0x8f/0xc0 [ice]
> > [ 6420.841343]  ice_service_task+0x23b/0x600 [ice]
> > [ 6420.845884]  ? __schedule+0x212/0x550
> > [ 6420.849550]  process_one_work+0x1e2/0x3b0
> > [ 6420.853563]  ? rescuer_thread+0x390/0x390
> > [ 6420.857577]  worker_thread+0x50/0x3a0
> > [ 6420.861242]  ? rescuer_thread+0x390/0x390
> > [ 6420.865253]  kthread+0xdd/0x100
> > [ 6420.868400]  ? kthread_complete_and_exit+0x20/0x20
> > [ 6420.873194]  ret_from_fork+0x1f/0x30
> > [ 6420.876774]  </TASK>
> > [ 6420.878967] Modules linked in: vfio_pci vfio_pci_core
> > vfio_iommu_type1 vfio iavf vhost_net vhost vhost_iotlb tap tun
> > xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4
> > nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6
> > nf_defrag_ipv4 nft_counter nf_tables bridge stp llc sctp
> > ip6_udp_tunnel udp_tunnel nfp tls nfnetlink bluetooth mlx4_en
> > mlx4_core rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd
> > grace fscache netfs rfkill sunrpc intel_rapl_msr intel_rapl_common
> > i10nm_edac nfit libnvdimm ipmi_ssif x86_pkg_temp_thermal
> > intel_powerclamp coretemp irdma kvm_intel i40e kvm iTCO_wdt dcdbas
> > ib_uverbs irqbypass iTCO_vendor_support mgag200 mei_me ib_core
> > dell_smbios isst_if_mmio isst_if_mbox_pci rapl i2c_algo_bit
> > drm_shmem_helper intel_cstate drm_kms_helper syscopyarea
> > sysfillrect isst_if_common sysimgblt intel_uncore fb_sys_fops
> > dell_wmi_descriptor wmi_bmof intel_vsec mei i2c_i801 acpi_ipmi
> > ipmi_si i2c_smbus ipmi_devintf intel_pch_thermal acpi_power_meter
> > pcspk
> >   r
> > 
> > Fixes: efe41860008e ("ice: Fix memory corruption in VF driver")
> > Fixes: f23df5220d2b ("ice: Fix spurious interrupt during removal of
> > trusted VF")
> > Signed-off-by: Petr Oros <poros@...hat.com>
> 
> Thank you for all of your testing efforts, detailed explanation,
> and the fix!
> 
> Is there anything interesting about your setup/methodology?
> (Asking rather to explore and extend our tests, no doubts here :)

This test is part of our QE test suite. There are a large number of
"cfg stress" tests.
I can't explain all the tests, but this one in particular just created
2 threads.
One attaching/detaching VF from VM and the other sets VF parameters in
a loop (trust, spoof check, mac addr) This causes concurrent access to
resources during reset. ice/iavf are very sensitive to this type of
stress ;) 

We also using LNST, but it currently catches other types of bugs.

> 
> > ---
> >   drivers/net/ethernet/intel/ice/ice_vf_lib.c | 15 ++++++++-------
> >   1 file changed, 8 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/ice/ice_vf_lib.c
> > b/drivers/net/ethernet/intel/ice/ice_vf_lib.c
> > index 294e91c3453ccd..ea3310be8354cf 100644
> > --- a/drivers/net/ethernet/intel/ice/ice_vf_lib.c
> > +++ b/drivers/net/ethernet/intel/ice/ice_vf_lib.c
> > @@ -612,11 +612,17 @@ int ice_reset_vf(struct ice_vf *vf, u32
> > flags)
> >                 return 0;
> >         }
> >   
> > +       if (flags & ICE_VF_RESET_LOCK)
> > +               mutex_lock(&vf->cfg_lock);
> > +       else
> > +               lockdep_assert_held(&vf->cfg_lock);
> > +
> >         if (ice_is_vf_disabled(vf)) {
> >                 vsi = ice_get_vf_vsi(vf);
> >                 if (!vsi) {
> >                         dev_dbg(dev, "VF is already removed\n");
> > -                       return -EINVAL;
> > +                       err = -EINVAL;
> > +                       goto out_unlock;
> >                 }
> >                 ice_vsi_stop_lan_tx_rings(vsi, ICE_NO_RESET, vf-
> > >vf_id);
> >   
> > @@ -625,14 +631,9 @@ int ice_reset_vf(struct ice_vf *vf, u32 flags)
> >   
> >                 dev_dbg(dev, "VF is already disabled, there is no
> > need for resetting it, telling VM, all is fine %d\n",
> >                         vf->vf_id);
> > -               return 0;
> > +               goto out_unlock;
> >         }
> >   
> > -       if (flags & ICE_VF_RESET_LOCK)
> > -               mutex_lock(&vf->cfg_lock);
> > -       else
> > -               lockdep_assert_held(&vf->cfg_lock);
> > -
> >         /* Set VF disable bit state here, before triggering reset
> > */
> >         set_bit(ICE_VF_STATE_DIS, vf->vf_states);
> >         ice_trigger_vf_reset(vf, flags & ICE_VF_RESET_VFLR, false);
> 

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