[PATCH 4.4 05/35] iwlwifi: mvm: guard against device removal in reprobe

Greg Kroah-Hartman
2021-02-22T13:30:12Z

From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit 7a21b1d4a728a483f07c638ccd8610d4b4f12684 ]

If we get into a problem severe enough to attempt a reprobe,
we schedule a worker to do that. However, if the problem gets
more severe and the device is actually destroyed before this
worker has a chance to run, we use a free device. Bump up the
reference count of the device until the worker runs to avoid
this situation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20210122144849.871f0892e4b2.I94819e11afd68d875f3e242b98bef724b8236f1e@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/iwlwifi/mvm/ops.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/iwlwifi/mvm/ops.c b/drivers/net/wireless/iwlwifi/mvm/ops.c
index 13c97f665ba88..bb81261de45fa 100644
--- a/drivers/net/wireless/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/iwlwifi/mvm/ops.c
@@ -909,6 +909,7 @@ static void iwl_mvm_reprobe_wk(struct work_struct *wk)
reprobe = container_of(wk, struct iwl_mvm_reprobe, work);
if (device_reprobe(reprobe->dev))
dev_err(reprobe->dev, "reprobe failed!\n");
+ put_device(reprobe->dev);
kfree(reprobe);
module_put(THIS_MODULE);
}
@@ -991,7 +992,7 @@ void iwl_mvm_nic_restart(struct iwl_mvm *mvm, bool fw_error)
module_put(THIS_MODULE);
return;
}
- reprobe->dev = mvm->trans->dev;
+ reprobe->dev = get_device(mvm->trans->dev);
INIT_WORK(&reprobe->work, iwl_mvm_reprobe_wk);
schedule_work(&reprobe->work);
} else if (mvm->cur_ucode == IWL_UCODE_REGULAR) {
--
2.27.0