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Message-ID: <MW5PR11MB5811B1CA163538BE14F58DA8DDF79@MW5PR11MB5811.namprd11.prod.outlook.com>
Date: Fri, 22 Apr 2022 17:12:50 +0000
From: "Ertman, David M" <david.m.ertman@...el.com>
To: ivecera <ivecera@...hat.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC: poros <poros@...hat.com>, mschmidt <mschmidt@...hat.com>,
Leon Romanovsky <leon@...nel.org>,
"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
"Nguyen, Anthony L" <anthony.l.nguyen@...el.com>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
"Saleem, Shiraz" <shiraz.saleem@...el.com>,
"moderated list:INTEL ETHERNET DRIVERS"
<intel-wired-lan@...ts.osuosl.org>,
open list <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH net v3] ice: Fix race during aux device (un)plugging
> -----Original Message-----
> From: Ivan Vecera <ivecera@...hat.com>
> Sent: Wednesday, April 20, 2022 11:09 PM
> To: netdev@...r.kernel.org
> Cc: poros <poros@...hat.com>; mschmidt <mschmidt@...hat.com>; Leon
> Romanovsky <leon@...nel.org>; Brandeburg, Jesse
> <jesse.brandeburg@...el.com>; Nguyen, Anthony L
> <anthony.l.nguyen@...el.com>; David S. Miller <davem@...emloft.net>;
> Jakub Kicinski <kuba@...nel.org>; Paolo Abeni <pabeni@...hat.com>;
> Ertman, David M <david.m.ertman@...el.com>; Saleem, Shiraz
> <shiraz.saleem@...el.com>; moderated list:INTEL ETHERNET DRIVERS <intel-
> wired-lan@...ts.osuosl.org>; open list <linux-kernel@...r.kernel.org>
> Subject: [PATCH net v3] ice: Fix race during aux device (un)plugging
>
> Function ice_plug_aux_dev() assigns pf->adev field too early prior
> aux device initialization and on other side ice_unplug_aux_dev()
> starts aux device deinit and at the end assigns NULL to pf->adev.
> This is wrong because pf->adev should always be non-NULL only when
> aux device is fully initialized and ready. This wrong order causes
> a crash when ice_send_event_to_aux() call occurs because that function
> depends on non-NULL value of pf->adev and does not assume that
> aux device is half-initialized or half-destroyed.
> After order correction the race window is tiny but it is still there,
> as Leon mentioned and manipulation with pf->adev needs to be protected
> by mutex.
>
> Fix (un-)plugging functions so pf->adev field is set after aux device
> init and prior aux device destroy and protect pf->adev assignment by
> new mutex. This mutex is also held during ice_send_event_to_aux()
> call to ensure that aux device is valid during that call. Device
> lock used ice_send_event_to_aux() to avoid its concurrent run can
> be removed as this is secured by that mutex.
>
> Reproducer:
> cycle=1
> while :;do
> echo "#### Cycle: $cycle"
>
> ip link set ens7f0 mtu 9000
> ip link add bond0 type bond mode 1 miimon 100
> ip link set bond0 up
> ifenslave bond0 ens7f0
> ip link set bond0 mtu 9000
> ethtool -L ens7f0 combined 1
> ip link del bond0
> ip link set ens7f0 mtu 1500
> sleep 1
>
> let cycle++
> done
>
> In short when the device is added/removed to/from bond the aux device
> is unplugged/plugged. When MTU of the device is changed an event is
> sent to aux device asynchronously. This can race with (un)plugging
> operation and because pf->adev is set too early (plug) or too late
> (unplug) the function ice_send_event_to_aux() can touch uninitialized
> or destroyed fields. In the case of crash below pf->adev->dev.mutex.
>
> Crash:
> [ 53.372066] bond0: (slave ens7f0): making interface the new active one
> [ 53.378622] bond0: (slave ens7f0): Enslaving as an active interface with an u
> p link
> [ 53.386294] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes
> ready
> [ 53.549104] bond0: (slave ens7f1): Enslaving as a backup interface with an
> up
> link
> [ 54.118906] ice 0000:ca:00.0 ens7f0: Number of in use tx queues changed
> inval
> idating tc mappings. Priority traffic classification disabled!
> [ 54.233374] ice 0000:ca:00.1 ens7f1: Number of in use tx queues changed
> inval
> idating tc mappings. Priority traffic classification disabled!
> [ 54.248204] bond0: (slave ens7f0): Releasing backup interface
> [ 54.253955] bond0: (slave ens7f1): making interface the new active one
> [ 54.274875] bond0: (slave ens7f1): Releasing backup interface
> [ 54.289153] bond0 (unregistering): Released all slaves
> [ 55.383179] MII link monitoring set to 100 ms
> [ 55.398696] bond0: (slave ens7f0): making interface the new active one
> [ 55.405241] BUG: kernel NULL pointer dereference, address:
> 0000000000000080
> [ 55.405289] bond0: (slave ens7f0): Enslaving as an active interface with an u
> p link
> [ 55.412198] #PF: supervisor write access in kernel mode
> [ 55.412200] #PF: error_code(0x0002) - not-present page
> [ 55.412201] PGD 25d2ad067 P4D 0
> [ 55.412204] Oops: 0002 [#1] PREEMPT SMP NOPTI
> [ 55.412207] CPU: 0 PID: 403 Comm: kworker/0:2 Kdump: loaded Tainted: G
> S
> 5.17.0-13579-g57f2d6540f03 #1
> [ 55.429094] bond0: (slave ens7f1): Enslaving as a backup interface with an
> up
> link
> [ 55.430224] Hardware name: Dell Inc. PowerEdge R750/06V45N, BIOS 1.4.4
> 10/07/
> 2021
> [ 55.430226] Workqueue: ice ice_service_task [ice]
> [ 55.468169] RIP: 0010:mutex_unlock+0x10/0x20
> [ 55.472439] Code: 0f b1 13 74 96 eb e0 4c 89 ee eb d8 e8 79 54 ff ff 66 0f 1f 84
> 00 00 00 00 00 0f 1f 44 00 00 65 48 8b 04 25 40 ef 01 00 31 d2 <f0> 48 0f b1 17 75
> 01 c3 e9 e3 fe ff ff 0f 1f 00 0f 1f 44 00 00 48
> [ 55.491186] RSP: 0018:ff4454230d7d7e28 EFLAGS: 00010246
> [ 55.496413] RAX: ff1a79b208b08000 RBX: ff1a79b2182e8880 RCX:
> 0000000000000001
> [ 55.503545] RDX: 0000000000000000 RSI: ff4454230d7d7db0 RDI:
> 0000000000000080
> [ 55.510678] RBP: ff1a79d1c7e48b68 R08: ff4454230d7d7db0 R09:
> 0000000000000041
> [ 55.517812] R10: 00000000000000a5 R11: 00000000000006e6 R12:
> ff1a79d1c7e48bc0
> [ 55.524945] R13: 0000000000000000 R14: ff1a79d0ffc305c0 R15:
> 0000000000000000
> [ 55.532076] FS: 0000000000000000(0000) GS:ff1a79d0ffc00000(0000)
> knlGS:0000000000000000
> [ 55.540163] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 55.545908] CR2: 0000000000000080 CR3: 00000003487ae003 CR4:
> 0000000000771ef0
> [ 55.553041] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000
> [ 55.560173] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> 0000000000000400
> [ 55.567305] PKRU: 55555554
> [ 55.570018] Call Trace:
> [ 55.572474] <TASK>
> [ 55.574579] ice_service_task+0xaab/0xef0 [ice]
> [ 55.579130] process_one_work+0x1c5/0x390
> [ 55.583141] ? process_one_work+0x390/0x390
> [ 55.587326] worker_thread+0x30/0x360
> [ 55.590994] ? process_one_work+0x390/0x390
> [ 55.595180] kthread+0xe6/0x110
> [ 55.598325] ? kthread_complete_and_exit+0x20/0x20
> [ 55.603116] ret_from_fork+0x1f/0x30
> [ 55.606698] </TASK>
>
> Fixes: f9f5301e7e2d ("ice: Register auxiliary device to provide RDMA")
> Cc: Leon Romanovsky <leon@...nel.org>
> Signed-off-by: Ivan Vecera <ivecera@...hat.com>
> ---
> drivers/net/ethernet/intel/ice/ice.h | 1 +
> drivers/net/ethernet/intel/ice/ice_idc.c | 33 ++++++++++++++---------
> drivers/net/ethernet/intel/ice/ice_main.c | 2 ++
> 3 files changed, 23 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice.h
> b/drivers/net/ethernet/intel/ice/ice.h
> index 8ed3c9ab7ff7..a895e3a8e988 100644
> --- a/drivers/net/ethernet/intel/ice/ice.h
> +++ b/drivers/net/ethernet/intel/ice/ice.h
> @@ -540,6 +540,7 @@ struct ice_pf {
> struct mutex avail_q_mutex; /* protects access to avail_[rx|tx]qs
> */
> struct mutex sw_mutex; /* lock for protecting VSI alloc
> flow */
> struct mutex tc_mutex; /* lock to protect TC changes
> */
> + struct mutex adev_mutex; /* lock to protect aux device access
> */
> u32 msg_enable;
> struct ice_ptp ptp;
> struct tty_driver *ice_gnss_tty_driver;
> diff --git a/drivers/net/ethernet/intel/ice/ice_idc.c
> b/drivers/net/ethernet/intel/ice/ice_idc.c
> index 25a436d342c2..b9e471137f6a 100644
> --- a/drivers/net/ethernet/intel/ice/ice_idc.c
> +++ b/drivers/net/ethernet/intel/ice/ice_idc.c
> @@ -10,13 +10,15 @@
> * ice_get_auxiliary_drv - retrieve iidc_auxiliary_drv struct
> * @pf: pointer to PF struct
> *
> - * This function has to be called with a device_lock on the
> - * pf->adev.dev to avoid race conditions.
> + * This function has to be called with pf->adev_mutex held
> + * to avoid race conditions.
> */
> static struct iidc_auxiliary_drv *ice_get_auxiliary_drv(struct ice_pf *pf)
> {
> struct auxiliary_device *adev;
>
> + lockdep_assert_held(&pf->adev_mutex);
> +
> adev = pf->adev;
> if (!adev || !adev->dev.driver)
> return NULL;
> @@ -37,14 +39,13 @@ void ice_send_event_to_aux(struct ice_pf *pf, struct
> iidc_event *event)
> if (WARN_ON_ONCE(!in_task()))
> return;
>
> - if (!pf->adev)
> - return;
> + mutex_lock(&pf->adev_mutex);
>
> - device_lock(&pf->adev->dev);
> iadrv = ice_get_auxiliary_drv(pf);
> if (iadrv && iadrv->event_handler)
> iadrv->event_handler(pf, event);
> - device_unlock(&pf->adev->dev);
> +
> + mutex_unlock(&pf->adev_mutex);
> }
>
> /**
> @@ -290,7 +291,6 @@ int ice_plug_aux_dev(struct ice_pf *pf)
> return -ENOMEM;
>
> adev = &iadev->adev;
> - pf->adev = adev;
> iadev->pf = pf;
>
> adev->id = pf->aux_idx;
> @@ -300,18 +300,20 @@ int ice_plug_aux_dev(struct ice_pf *pf)
>
> ret = auxiliary_device_init(adev);
> if (ret) {
> - pf->adev = NULL;
> kfree(iadev);
> return ret;
> }
>
> ret = auxiliary_device_add(adev);
> if (ret) {
> - pf->adev = NULL;
> auxiliary_device_uninit(adev);
> return ret;
> }
>
> + mutex_lock(&pf->adev_mutex);
> + pf->adev = adev;
> + mutex_unlock(&pf->adev_mutex);
> +
> return 0;
> }
>
> @@ -320,12 +322,17 @@ int ice_plug_aux_dev(struct ice_pf *pf)
> */
> void ice_unplug_aux_dev(struct ice_pf *pf)
> {
> - if (!pf->adev)
> - return;
> + struct auxiliary_device *adev;
>
> - auxiliary_device_delete(pf->adev);
> - auxiliary_device_uninit(pf->adev);
> + mutex_lock(&pf->adev_mutex);
> + adev = pf->adev;
> pf->adev = NULL;
> + mutex_unlock(&pf->adev_mutex);
> +
> + if (adev) {
> + auxiliary_device_delete(adev);
> + auxiliary_device_uninit(adev);
> + }
> }
>
> /**
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c
> b/drivers/net/ethernet/intel/ice/ice_main.c
> index 5b1198859da7..2cbbf7abefc4 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -3769,6 +3769,7 @@ u16 ice_get_avail_rxq_count(struct ice_pf *pf)
> static void ice_deinit_pf(struct ice_pf *pf)
> {
> ice_service_task_stop(pf);
> + mutex_destroy(&pf->adev_mutex);
> mutex_destroy(&pf->sw_mutex);
> mutex_destroy(&pf->tc_mutex);
> mutex_destroy(&pf->avail_q_mutex);
> @@ -3847,6 +3848,7 @@ static int ice_init_pf(struct ice_pf *pf)
>
> mutex_init(&pf->sw_mutex);
> mutex_init(&pf->tc_mutex);
> + mutex_init(&pf->adev_mutex);
>
> INIT_HLIST_HEAD(&pf->aq_wait_list);
> spin_lock_init(&pf->aq_wait_lock);
> --
> 2.35.1
ack
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