From: Tony Nguyen <anthony.l.nguyen@intel.com>
To: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
edumazet@google.com, netdev@vger.kernel.org
Cc: Lin Ma <linma@zju.edu.cn>,
anthony.l.nguyen@intel.com, stable@vger.kernel.org,
Corinna Vinschen <vinschen@redhat.com>,
Jacob Keller <jacob.e.keller@intel.com>,
Simon Horman <simon.horman@corigine.com>,
Rafal Romanowski <rafal.romanowski@intel.com>
Subject: [PATCH net 1/5] igb: revert rtnl_lock() that causes deadlock
Date: Thu, 16 Mar 2023 10:31:40 -0700 [thread overview]
Message-ID: <20230316173144.2003469-2-anthony.l.nguyen@intel.com> (raw)
In-Reply-To: <20230316173144.2003469-1-anthony.l.nguyen@intel.com>
From: Lin Ma <linma@zju.edu.cn>
The commit 6faee3d4ee8b ("igb: Add lock to avoid data race") adds
rtnl_lock to eliminate a false data race shown below
(FREE from device detaching) | (USE from netdev core)
igb_remove | igb_ndo_get_vf_config
igb_disable_sriov | vf >= adapter->vfs_allocated_count?
kfree(adapter->vf_data) |
adapter->vfs_allocated_count = 0 |
| memcpy(... adapter->vf_data[vf]
The above race will never happen and the extra rtnl_lock causes deadlock
below
[ 141.420169] <TASK>
[ 141.420672] __schedule+0x2dd/0x840
[ 141.421427] schedule+0x50/0xc0
[ 141.422041] schedule_preempt_disabled+0x11/0x20
[ 141.422678] __mutex_lock.isra.13+0x431/0x6b0
[ 141.423324] unregister_netdev+0xe/0x20
[ 141.423578] igbvf_remove+0x45/0xe0 [igbvf]
[ 141.423791] pci_device_remove+0x36/0xb0
[ 141.423990] device_release_driver_internal+0xc1/0x160
[ 141.424270] pci_stop_bus_device+0x6d/0x90
[ 141.424507] pci_stop_and_remove_bus_device+0xe/0x20
[ 141.424789] pci_iov_remove_virtfn+0xba/0x120
[ 141.425452] sriov_disable+0x2f/0xf0
[ 141.425679] igb_disable_sriov+0x4e/0x100 [igb]
[ 141.426353] igb_remove+0xa0/0x130 [igb]
[ 141.426599] pci_device_remove+0x36/0xb0
[ 141.426796] device_release_driver_internal+0xc1/0x160
[ 141.427060] driver_detach+0x44/0x90
[ 141.427253] bus_remove_driver+0x55/0xe0
[ 141.427477] pci_unregister_driver+0x2a/0xa0
[ 141.428296] __x64_sys_delete_module+0x141/0x2b0
[ 141.429126] ? mntput_no_expire+0x4a/0x240
[ 141.429363] ? syscall_trace_enter.isra.19+0x126/0x1a0
[ 141.429653] do_syscall_64+0x5b/0x80
[ 141.429847] ? exit_to_user_mode_prepare+0x14d/0x1c0
[ 141.430109] ? syscall_exit_to_user_mode+0x12/0x30
[ 141.430849] ? do_syscall_64+0x67/0x80
[ 141.431083] ? syscall_exit_to_user_mode_prepare+0x183/0x1b0
[ 141.431770] ? syscall_exit_to_user_mode+0x12/0x30
[ 141.432482] ? do_syscall_64+0x67/0x80
[ 141.432714] ? exc_page_fault+0x64/0x140
[ 141.432911] entry_SYSCALL_64_after_hwframe+0x72/0xdc
Since the igb_disable_sriov() will call pci_disable_sriov() before
releasing any resources, the netdev core will synchronize the cleanup to
avoid any races. This patch removes the useless rtnl_(un)lock to guarantee
correctness.
CC: stable@vger.kernel.org
Fixes: 6faee3d4ee8b ("igb: Add lock to avoid data race")
Reported-by: Corinna Vinschen <vinschen@redhat.com>
Link: https://lore.kernel.org/intel-wired-lan/ZAcJvkEPqWeJHO2r@calimero.vinschen.de/
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Tested-by: Corinna Vinschen <vinschen@redhat.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
drivers/net/ethernet/intel/igb/igb_main.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 03bc1e8af575..5532361b0e94 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -3863,9 +3863,7 @@ static void igb_remove(struct pci_dev *pdev)
igb_release_hw_control(adapter);
#ifdef CONFIG_PCI_IOV
- rtnl_lock();
igb_disable_sriov(pdev);
- rtnl_unlock();
#endif
unregister_netdev(netdev);
--
2.38.1
next prev parent reply other threads:[~2023-03-16 17:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-16 17:31 [PATCH net 0/5][pull request] Intel Wired LAN Driver Updates 2023-03-16 (igb, igbvf, igc) Tony Nguyen
2023-03-16 17:31 ` Tony Nguyen [this message]
2023-03-16 17:31 ` [PATCH net 2/5] igb: Enable SR-IOV after reinit Tony Nguyen
2023-03-16 17:31 ` [PATCH net 3/5] intel/igbvf: free irq on the error path in igbvf_request_msix() Tony Nguyen
2023-03-16 17:31 ` [PATCH net 4/5] igbvf: Regard vf reset nack as success Tony Nguyen
2023-03-16 17:31 ` [PATCH net 5/5] igc: fix the validation logic for taprio's gate list Tony Nguyen
2023-03-19 10:50 ` [PATCH net 0/5][pull request] Intel Wired LAN Driver Updates 2023-03-16 (igb, igbvf, igc) patchwork-bot+netdevbpf
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