[PATCH 5.17 015/114] ice: Fix race during aux device (un)plugging

Greg Kroah-Hartman
2022-05-16T20:24:50Z

From: Ivan Vecera <ivecera@redhat.com>

[ Upstream commit 486b9eee57ddca5c9a2d59fc41153f36002e0a00 ]

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.
Note that device lock used ice_send_event_to_aux() needs to be kept
to avoid race with aux drv unload.

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")
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Reviewed-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/ice/ice.h | 1 +
drivers/net/ethernet/intel/ice/ice_idc.c | 25 +++++++++++++++--------
drivers/net/ethernet/intel/ice/ice_main.c | 2 ++
3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index 9c04a71a9fca..e2ffdf2726fd 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -546,6 +546,7 @@ 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;
u16 num_rdma_msix; /* Total MSIX vectors for RDMA driver */
diff --git a/drivers/net/ethernet/intel/ice/ice_idc.c b/drivers/net/ethernet/intel/ice/ice_idc.c
index 5559230eff8b..0deed090645f 100644
--- a/drivers/net/ethernet/intel/ice/ice_idc.c
+++ b/drivers/net/ethernet/intel/ice/ice_idc.c
@@ -37,14 +37,17 @@ void ice_send_event_to_aux(struct ice_pf *pf, struct iidc_event *event)
if (WARN_ON_ONCE(!in_task()))
return;

+ mutex_lock(&pf->adev_mutex);
if (!pf->adev)
- return;
+ goto finish;

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);
+finish:
+ mutex_unlock(&pf->adev_mutex);
}

/**
@@ -285,7 +288,6 @@ 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;
@@ -295,18 +297,20 @@ 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;
}

@@ -315,12 +319,17 @@ 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 e347030ee2e3..7f6715eb862f 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -3682,6 +3682,7 @@ 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);
@@ -3762,6 +3763,7 @@ 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