| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <15388e7f-45a8-4356-88c9-45848c3a296f@huawei.com>
Date: Fri, 1 Aug 2025 18:44:36 +0800
From: Jijie Shao <shaojijie@...wei.com>
To: Simon Horman <horms@...nel.org>
CC: <shaojijie@...wei.com>, <davem@...emloft.net>, <edumazet@...gle.com>,
<kuba@...nel.org>, <pabeni@...hat.com>, <andrew+netdev@...n.ch>,
<shenjian15@...wei.com>, <liuyonglong@...wei.com>, <chenhao418@...wei.com>,
<jonathan.cameron@...wei.com>, <shameerali.kolothum.thodi@...wei.com>,
<salil.mehta@...wei.com>, <netdev@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net 1/3] net: hibmcge: fix rtnl deadlock issue
on 2025/8/1 18:05, Simon Horman wrote:
> On Thu, Jul 31, 2025 at 09:47:47PM +0800, Jijie Shao wrote:
>> Currently, the hibmcge netdev acquires the rtnl_lock in
>> pci_error_handlers.reset_prepare() and releases it in
>> pci_error_handlers.reset_done().
>>
>> However, in the PCI framework:
>> pci_reset_bus - __pci_reset_slot - pci_slot_save_and_disable_locked -
>> pci_dev_save_and_disable - err_handler->reset_prepare(dev);
>>
>> In pci_slot_save_and_disable_locked():
>> list_for_each_entry(dev, &slot->bus->devices, bus_list) {
>> if (!dev->slot || dev->slot!= slot)
>> continue;
>> pci_dev_save_and_disable(dev);
>> if (dev->subordinate)
>> pci_bus_save_and_disable_locked(dev->subordinate);
>> }
>>
>> This will iterate through all devices under the current bus and execute
>> err_handler->reset_prepare(), causing two devices of the hibmcge driver
>> to sequentially request the rtnl_lock, leading to a deadlock.
>>
>> Since the driver now executes netif_device_detach()
>> before the reset process, it will not concurrently with
>> other netdev APIs, so there is no need to hold the rtnl_lock now.
>>
>> Therefore, this patch removes the rtnl_lock during the reset process and
>> adjusts the position of HBG_NIC_STATE_RESETTING to ensure
>> that multiple resets are not executed concurrently.
>>
>> Fixes: 3f5a61f6d504f ("net: hibmcge: Add reset supported in this module")
>> Signed-off-by: Jijie Shao <shaojijie@...wei.com>
>> ---
>> drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c | 13 ++++---------
>> 1 file changed, 4 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c b/drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c
>> index 503cfbfb4a8a..94bc6f0da912 100644
>> --- a/drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c
>> +++ b/drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c
>> @@ -53,9 +53,11 @@ static int hbg_reset_prepare(struct hbg_priv *priv, enum hbg_reset_type type)
>> {
>> int ret;
>>
>> - ASSERT_RTNL();
>> + if (test_and_set_bit(HBG_NIC_STATE_RESETTING, &priv->state))
>> + return -EBUSY;
>>
>> if (netif_running(priv->netdev)) {
>> + clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
>> dev_warn(&priv->pdev->dev,
>> "failed to reset because port is up\n");
>> return -EBUSY;
>> @@ -64,7 +66,6 @@ static int hbg_reset_prepare(struct hbg_priv *priv, enum hbg_reset_type type)
>> netif_device_detach(priv->netdev);
>>
>> priv->reset_type = type;
>> - set_bit(HBG_NIC_STATE_RESETTING, &priv->state);
>> clear_bit(HBG_NIC_STATE_RESET_FAIL, &priv->state);
>> ret = hbg_hw_event_notify(priv, HBG_HW_EVENT_RESET);
>> if (ret) {
>> @@ -84,10 +85,8 @@ static int hbg_reset_done(struct hbg_priv *priv, enum hbg_reset_type type)
>> type != priv->reset_type)
>> return 0;
>>
>> - ASSERT_RTNL();
>> -
>> - clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
>> ret = hbg_rebuild(priv);
>> + clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
> Hi Jijie,
>
> If I understand things correctly, then with this patch the
> HBG_NIC_STATE_RESETTING bit is used to prevent concurrent execution.
>
> Noting that a reset may be triggered via eththool, where hbg_reset() is
> used as a callback, I am concerned about concurrency implications for lines
> below this one.
Yes, just like the following, it can lead to reset and net open concurrency.
===========
reset1 reset2 open
set_bit HBG_NIC_STATE_RESETTING
netif_device_detach()
resetting...
clear_bit HBG_NIC_STATE_RESETTING
set_bit HBG_NIC_STATE_RESETTING
netif_device_detach()
netif_device_attach()
resetting... hbg_net_open()
hbg_txrx_init()
clear_bit HBG_NIC_STATE_RESETTING
netif_device_attach()
============
Thank you for your reminder.
I will fix it in V2
Jijie Shao
>> if (ret) {
>> priv->stats.reset_fail_cnt++;
>> set_bit(HBG_NIC_STATE_RESET_FAIL, &priv->state);
>> @@ -101,12 +100,10 @@ static int hbg_reset_done(struct hbg_priv *priv, enum hbg_reset_type type)
>> return ret;
>> }
>>
>> -/* must be protected by rtnl lock */
>> int hbg_reset(struct hbg_priv *priv)
>> {
>> int ret;
>>
>> - ASSERT_RTNL();
>> ret = hbg_reset_prepare(priv, HBG_RESET_TYPE_FUNCTION);
>> if (ret)
>> return ret;
>> @@ -171,7 +168,6 @@ static void hbg_pci_err_reset_prepare(struct pci_dev *pdev)
>> struct net_device *netdev = pci_get_drvdata(pdev);
>> struct hbg_priv *priv = netdev_priv(netdev);
>>
>> - rtnl_lock();
>> hbg_reset_prepare(priv, HBG_RESET_TYPE_FLR);
>> }
>>
>> @@ -181,7 +177,6 @@ static void hbg_pci_err_reset_done(struct pci_dev *pdev)
>> struct hbg_priv *priv = netdev_priv(netdev);
>>
>> hbg_reset_done(priv, HBG_RESET_TYPE_FLR);
>> - rtnl_unlock();
>> }
>>
>> static const struct pci_error_handlers hbg_pci_err_handler = {
>> --
>> 2.33.0
>>
Powered by blists - more mailing lists