RE: [EXT] Re: [net PATCH 5/9] octeontx2-pf: mcs: Fix NULL pointer dereferences

[Subbaraya Sundeep Bhatta]

Hi,

>-----Original Message-----
>From: Leon Romanovsky <leon@xxxxxxxxxx>
>Sent: Sunday, April 23, 2023 10:22 PM
>To: Geethasowjanya Akula <gakula@xxxxxxxxxxx>
>Cc: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kuba@xxxxxxxxxx;
>davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; pabeni@xxxxxxxxxx;
>richardcochran@xxxxxxxxx; Sunil Kovvuri Goutham
><sgoutham@xxxxxxxxxxx>; Subbaraya Sundeep Bhatta
><sbhatta@xxxxxxxxxxx>; Hariprasad Kelam <hkelam@xxxxxxxxxxx>
>Subject: [EXT] Re: [net PATCH 5/9] octeontx2-pf: mcs: Fix NULL pointer
>dereferences
>
>On Sun, Apr 23, 2023 at 03:24:50PM +0530, Geetha sowjanya wrote:
>> From: Subbaraya Sundeep <sbhatta@xxxxxxxxxxx>
>>
>> When system is rebooted after creating macsec interface below NULL
>> pointer dereference crashes occurred. This patch fixes those crashes.
>>
>> [ 3324.406942] Unable to handle kernel NULL pointer dereference at
>> virtual address 0000000000000000 [ 3324.415726] Mem abort info:
>> [ 3324.418510]   ESR = 0x96000006
>> [ 3324.421557]   EC = 0x25: DABT (current EL), IL = 32 bits
>> [ 3324.426865]   SET = 0, FnV = 0
>> [ 3324.429913]   EA = 0, S1PTW = 0
>> [ 3324.433047] Data abort info:
>> [ 3324.435921]   ISV = 0, ISS = 0x00000006
>> [ 3324.439748]   CM = 0, WnR = 0
>> ....
>> [ 3324.575915] Call trace:
>> [ 3324.578353]  cn10k_mdo_del_secy+0x24/0x180 [ 3324.582440]
>> macsec_common_dellink+0xec/0x120 [ 3324.586788]
>> macsec_notify+0x17c/0x1c0 [ 3324.590529]
>> raw_notifier_call_chain+0x50/0x70 [ 3324.594965]
>> call_netdevice_notifiers_info+0x34/0x7c
>> [ 3324.599921]  rollback_registered_many+0x354/0x5bc
>> [ 3324.604616]  unregister_netdevice_queue+0x88/0x10c
>> [ 3324.609399]  unregister_netdev+0x20/0x30 [ 3324.613313]
>> otx2_remove+0x8c/0x310 [ 3324.616794]  pci_device_shutdown+0x30/0x70
>[
>> 3324.620882]  device_shutdown+0x11c/0x204
>>
>> [  966.664930] Unable to handle kernel NULL pointer dereference at
>> virtual address 0000000000000000 [  966.673712] Mem abort info:
>> [  966.676497]   ESR = 0x96000006
>> [  966.679543]   EC = 0x25: DABT (current EL), IL = 32 bits
>> [  966.684848]   SET = 0, FnV = 0
>> [  966.687895]   EA = 0, S1PTW = 0
>> [  966.691028] Data abort info:
>> [  966.693900]   ISV = 0, ISS = 0x00000006
>> [  966.697729]   CM = 0, WnR = 0
>> ....
>> [  966.833467] Call trace:
>> [  966.835904]  cn10k_mdo_stop+0x20/0xa0 [  966.839557]
>> macsec_dev_stop+0xe8/0x11c [  966.843384]
>__dev_close_many+0xbc/0x140
>> [  966.847298]  dev_close_many+0x84/0x120 [  966.851039]
>> rollback_registered_many+0x114/0x5bc
>> [  966.855735]  unregister_netdevice_many.part.0+0x14/0xa0
>> [  966.860952]  unregister_netdevice_many+0x18/0x24
>> [  966.865560]  macsec_notify+0x1ac/0x1c0 [  966.869303]
>> raw_notifier_call_chain+0x50/0x70 [  966.873738]
>> call_netdevice_notifiers_info+0x34/0x7c
>> [  966.878694]  rollback_registered_many+0x354/0x5bc
>> [  966.883390]  unregister_netdevice_queue+0x88/0x10c
>> [  966.888173]  unregister_netdev+0x20/0x30 [  966.892090]
>> otx2_remove+0x8c/0x310 [  966.895571]  pci_device_shutdown+0x30/0x70 [
>> 966.899660]  device_shutdown+0x11c/0x204 [  966.903574]
>> __do_sys_reboot+0x208/0x290 [  966.907487]
>> __arm64_sys_reboot+0x20/0x30 [  966.911489]
>> el0_svc_handler+0x80/0x1c0 [  966.915316]  el0_svc+0x8/0x180 [
>> 966.918362] Code: f9400000 f9400a64 91220014 f94b3403 (f9400060) [
>> 966.924448] ---[ end trace 341778e799c3d8d7 ]---
>>
>> Fixes: c54ffc73601c ("octeontx2-pf: mcs: Introduce MACSEC hardware
>> offloading")
>> Signed-off-by: Subbaraya Sundeep <sbhatta@xxxxxxxxxxx>
>> Signed-off-by: Sunil Goutham <sgoutham@xxxxxxxxxxx>
>> Signed-off-by: Geetha sowjanya <gakula@xxxxxxxxxxx>
>> ---
>>  drivers/net/ethernet/marvell/octeontx2/nic/cn10k_macsec.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_macsec.c
>> b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_macsec.c
>> index 9ec5f38d38a8..5f4402f7b03e 100644
>> --- a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_macsec.c
>> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_macsec.c
>> @@ -1065,6 +1065,9 @@ static int cn10k_mdo_stop(struct macsec_context
>*ctx)
>>  	struct cn10k_mcs_txsc *txsc;
>>  	int err;
>>
>> +	if (!cfg)
>> +		return 0;
>> +
>>  	txsc = cn10k_mcs_get_txsc(cfg, ctx->secy);
>>  	if (!txsc)
>>  		return -ENOENT;
>> @@ -1146,6 +1149,9 @@ static int cn10k_mdo_del_secy(struct
>macsec_context *ctx)
>>  	struct cn10k_mcs_cfg *cfg = pfvf->macsec_cfg;
>>  	struct cn10k_mcs_txsc *txsc;
>>
>> +	if (!cfg)
>> +		return 0;
>
>How did you get call to .mdo_del_secy if you didn't add any secy?
>
>Thanks
>
It is because of the order of teardown in otx2_remove:
        cn10k_mcs_free(pf);
        unregister_netdev(netdev);

cn10k_mcs_free free the resources and makes cfg as NULL.
Later unregister_netdev calls mdo_del_secy and finds cfg as NULL.
Thanks for the review I will change the order and submit next version.

Sundeep

>> +
>>  	txsc = cn10k_mcs_get_txsc(cfg, ctx->secy);
>>  	if (!txsc)
>>  		return -ENOENT;
>> --
>> 2.25.1
>>