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 and can causes a crash when ice_send_event_to_aux()
call occurs during these operations because that function depends
on non-NULL value of pf->adev and does not assume that aux device
is half-initialized or half-destroyed.
Modify affected functions so pf->adev field is set after aux device
init and prior aux device destroy.
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) and the function ice_send_event_to_aux() can touch
uninitialized or destroyed fields (e.g. pf->adev->dev.mutex like
in the following 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")
Signed-off-by: Ivan Vecera <[email protected]>
---
drivers/net/ethernet/intel/ice/ice_idc.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_idc.c b/drivers/net/ethernet/intel/ice/ice_idc.c
index 25a436d342c2..4d889049231b 100644
--- a/drivers/net/ethernet/intel/ice/ice_idc.c
+++ b/drivers/net/ethernet/intel/ice/ice_idc.c
@@ -290,7 +290,6 @@ 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 +299,18 @@ 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;
}
+ pf->adev = adev;
+
return 0;
}
@@ -320,12 +319,14 @@ int ice_plug_aux_dev(struct ice_pf *pf)
*/
void ice_unplug_aux_dev(struct ice_pf *pf)
{
- if (!pf->adev)
+ struct auxiliary_device *adev = pf->adev;
+
+ if (!adev)
return;
- auxiliary_device_delete(pf->adev);
- auxiliary_device_uninit(pf->adev);
pf->adev = NULL;
+ auxiliary_device_delete(adev);
+ auxiliary_device_uninit(adev);
}
/**
--
2.35.1
On Fri, 15 Apr 2022 13:12:03 +0200
Michal Schmidt <[email protected]> wrote:
> On Thu, Apr 14, 2022 at 6:39 PM Ivan Vecera <[email protected]> wrote:
>
> > 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 and can causes a crash when ice_send_event_to_aux()
> > call occurs during these operations because that function depends
> > on non-NULL value of pf->adev and does not assume that aux device
> > is half-initialized or half-destroyed.
> >
> > Modify affected functions so pf->adev field is set after aux device
> > init and prior aux device destroy.
> >
> [...]
>
> > @@ -320,12 +319,14 @@ int ice_plug_aux_dev(struct ice_pf *pf)
> > */
> > void ice_unplug_aux_dev(struct ice_pf *pf)
> > {
> > - if (!pf->adev)
> > + struct auxiliary_device *adev = pf->adev;
> > +
> > + if (!adev)
> > return;
> >
> > - auxiliary_device_delete(pf->adev);
> > - auxiliary_device_uninit(pf->adev);
> > pf->adev = NULL;
> > + auxiliary_device_delete(adev);
> > + auxiliary_device_uninit(adev);
> > }
> >
>
> Hi Ivan,
> What prevents ice_unplug_aux_dev() from running immediately after
> ice_send_event_to_aux() gets past its "if (!pf->adev)" test ?
> Michal
ice_send_event_to_aux() takes aux device lock. ice_unplug_aux_dev()
calls auxiliary_device_delete() that calls device_del(). device_del()
takes device_lock() prior kill_device(). So if ice_send_event_to_aux()
is in progress then device_del() waits for its completion.
Thanks,
Ivan
On Fri, Apr 15, 2022 at 05:49:32PM +0200, Ivan Vecera wrote:
> On Fri, 15 Apr 2022 13:12:03 +0200
> Michal Schmidt <[email protected]> wrote:
>
> > On Thu, Apr 14, 2022 at 6:39 PM Ivan Vecera <[email protected]> wrote:
> >
> > > 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 and can causes a crash when ice_send_event_to_aux()
> > > call occurs during these operations because that function depends
> > > on non-NULL value of pf->adev and does not assume that aux device
> > > is half-initialized or half-destroyed.
> > >
> > > Modify affected functions so pf->adev field is set after aux device
> > > init and prior aux device destroy.
> > >
> > [...]
> >
> > > @@ -320,12 +319,14 @@ int ice_plug_aux_dev(struct ice_pf *pf)
> > > */
> > > void ice_unplug_aux_dev(struct ice_pf *pf)
> > > {
> > > - if (!pf->adev)
> > > + struct auxiliary_device *adev = pf->adev;
> > > +
> > > + if (!adev)
> > > return;
> > >
> > > - auxiliary_device_delete(pf->adev);
> > > - auxiliary_device_uninit(pf->adev);
> > > pf->adev = NULL;
> > > + auxiliary_device_delete(adev);
> > > + auxiliary_device_uninit(adev);
> > > }
> > >
> >
> > Hi Ivan,
> > What prevents ice_unplug_aux_dev() from running immediately after
> > ice_send_event_to_aux() gets past its "if (!pf->adev)" test ?
> > Michal
>
> ice_send_event_to_aux() takes aux device lock. ice_unplug_aux_dev()
> calls auxiliary_device_delete() that calls device_del(). device_del()
> takes device_lock() prior kill_device(). So if ice_send_event_to_aux()
> is in progress then device_del() waits for its completion.
Not really, you nullify pf->adev without any lock protection and
ice_send_event_to_aux() will simply crash.
CPU#1 | CPU#2
| ice_send_event_to_aux
ice_unplug_aux_dev() | ...
... |
pf->adev = NULL; |
| device_lock(&pf->adev->dev); <--- crash here.
Thanks
>
> Thanks,
> Ivan
>