Previously, e1000_down called cancel_work_sync for the e1000 reset task
(via e1000_down_and_stop), which takes RTNL.
As reported by users and syzbot, a deadlock is possible due to lock
inversion in the following scenario:
CPU 0:
- RTNL is held
- e1000_close
- e1000_down
- cancel_work_sync (takes the work queue mutex)
- e1000_reset_task
CPU 1:
- process_one_work (takes the work queue mutex)
- e1000_reset_task (takes RTNL)
To remedy this, avoid calling cancel_work_sync from e1000_down
(e1000_reset_task does nothing if the device is down anyway). Instead,
call cancel_work_sync for e1000_reset_task when the device is being
removed.
Fixes: e400c7444d84 ("e1000: Hold RTNL when e1000_down can be called")
Reported-by: [email protected]
Closes:
https://lore.kernel.org/netdev/[email protected]/
Reported-by: John <[email protected]>
Closes:
https://lore.kernel.org/netdev/CAP=Rh=OEsn4y_2LvkO3UtDWurKcGPnZ_NPSXK=fbgygnxl3...@mail.gmail.com/
Signed-off-by: Joe Damato <[email protected]>
---
drivers/net/ethernet/intel/e1000/e1000_main.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c
b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 3f089c3d47b2..d8595e84326d 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -477,10 +477,6 @@ static void e1000_down_and_stop(struct e1000_adapter
*adapter)
cancel_delayed_work_sync(&adapter->phy_info_task);
cancel_delayed_work_sync(&adapter->fifo_stall_task);
-
- /* Only kill reset task if adapter is not resetting */
- if (!test_bit(__E1000_RESETTING, &adapter->flags))
- cancel_work_sync(&adapter->reset_task);
}
void e1000_down(struct e1000_adapter *adapter)
@@ -1266,6 +1262,10 @@ static void e1000_remove(struct pci_dev *pdev)
unregister_netdev(netdev);
+ /* Only kill reset task if adapter is not resetting */
+ if (!test_bit(__E1000_RESETTING, &adapter->flags))
+ cancel_work_sync(&adapter->reset_task);
+
e1000_phy_hw_reset(hw);
kfree(adapter->tx_ring);
--
2.43.0
