From: Karen Sornek <karen.sornek@intel.com>
Date: Wed, 12 Jan 2022 10:19:47 +0100
Subject: i40e: Fix reset path while removing the driver
Patch-mainline: v5.17-rc3
Git-commit: 6533e558c6505e94c3e0ed4281ed5e31ec985f4d
References: git-fixes

Fix the crash in kernel while dereferencing the NULL pointer,
when the driver is unloaded and simultaneously the VSI rings
are being stopped.

The hardware requires 50msec in order to finish RX queues
disable. For this purpose the driver spins in mdelay function
for the operation to be completed.

For example changing number of queues which requires reset would
fail in the following call stack:

1) i40e_prep_for_reset
2) i40e_pf_quiesce_all_vsi
3) i40e_quiesce_vsi
4) i40e_vsi_close
5) i40e_down
6) i40e_vsi_stop_rings
7) i40e_vsi_control_rx -> disable requires the delay of 50msecs
8) continue back in i40e_down function where
   i40e_clean_tx_ring(vsi->tx_rings[i]) is going to crash

When the driver was spinning vsi_release called
i40e_vsi_free_arrays where the vsi->tx_rings resources
were freed and the pointer was set to NULL.

Fixes: 5b6d4a7f20b0 ("i40e: Fix crash during removing i40e driver")
Signed-off-by: Slawomir Laba <slawomirx.laba@intel.com>
Signed-off-by: Sylwester Dziedziuch <sylwesterx.dziedziuch@intel.com>
Signed-off-by: Karen Sornek <karen.sornek@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/i40e/i40e.h      |    1 +
 drivers/net/ethernet/intel/i40e/i40e_main.c |   19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -144,6 +144,7 @@ enum i40e_state_t {
 	__I40E_VIRTCHNL_OP_PENDING,
 	__I40E_RECOVERY_MODE,
 	__I40E_VF_RESETS_DISABLED,	/* disable resets during i40e_remove */
+	__I40E_IN_REMOVE,
 	__I40E_VFS_RELEASING,
 	/* This must be last as it determines the size of the BITMAP */
 	__I40E_STATE_SIZE__,
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -10863,6 +10863,9 @@ static void i40e_reset_and_rebuild(struc
 				   bool lock_acquired)
 {
 	int ret;
+
+	if (test_bit(__I40E_IN_REMOVE, pf->state))
+		return;
 	/* Now we wait for GRST to settle out.
 	 * We don't have to delete the VEBs or VSIs from the hw switch
 	 * because the reset will make them disappear.
@@ -12222,6 +12225,8 @@ int i40e_reconfig_rss_queues(struct i40e
 
 		vsi->req_queue_pairs = queue_count;
 		i40e_prep_for_reset(pf);
+		if (test_bit(__I40E_IN_REMOVE, pf->state))
+			return pf->alloc_rss_size;
 
 		pf->alloc_rss_size = new_rss_size;
 
@@ -13048,6 +13053,10 @@ static int i40e_xdp_setup(struct i40e_vs
 	if (need_reset)
 		i40e_prep_for_reset(pf);
 
+	/* VSI shall be deleted in a moment, just return EINVAL */
+	if (test_bit(__I40E_IN_REMOVE, pf->state))
+		return -EINVAL;
+
 	old_prog = xchg(&vsi->xdp_prog, prog);
 
 	if (need_reset) {
@@ -15938,8 +15947,13 @@ static void i40e_remove(struct pci_dev *
 	i40e_write_rx_ctl(hw, I40E_PFQF_HENA(0), 0);
 	i40e_write_rx_ctl(hw, I40E_PFQF_HENA(1), 0);
 
-	while (test_bit(__I40E_RESET_RECOVERY_PENDING, pf->state))
+	/* Grab __I40E_RESET_RECOVERY_PENDING and set __I40E_IN_REMOVE
+	 * flags, once they are set, i40e_rebuild should not be called as
+	 * i40e_prep_for_reset always returns early.
+	 */
+	while (test_and_set_bit(__I40E_RESET_RECOVERY_PENDING, pf->state))
 		usleep_range(1000, 2000);
+	set_bit(__I40E_IN_REMOVE, pf->state);
 
 	if (pf->flags & I40E_FLAG_SRIOV_ENABLED) {
 		set_bit(__I40E_VF_RESETS_DISABLED, pf->state);
@@ -16138,6 +16152,9 @@ static void i40e_pci_error_reset_done(st
 {
 	struct i40e_pf *pf = pci_get_drvdata(pdev);
 
+	if (test_bit(__I40E_IN_REMOVE, pf->state))
+		return;
+
 	i40e_reset_and_rebuild(pf, false, false);
 }