[PATCH net 7/9] bnxt_en: Check abort error state in bnxt_half_open_nic()

[Michael Chan <michael.chan@broadcom.com>]

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From: Somnath Kotur <somnath.kotur@broadcom.com>

bnxt_half_open_nic() is called during during ethtool self test and is
protected by rtnl_lock.  Firmware reset can be happening at the same
time.  Only critical portions of the entire firmware reset sequence
are protected by the rtnl_lock.  It is possible that bnxt_half_open_nic()
can be called when the firmware reset sequence is aborting.  In that
case, bnxt_half_open_nic() needs to check if the ABORT_ERR flag is set
and abort if it is.  The ethtool self test will fail but the NIC will be
brought to a consistent IF_DOWN state.

Without this patch, if bnxt_half_open_nic() were to continue in this
error state, it may crash like this:

  bnxt_en 0000:82:00.1 enp130s0f1np1: FW reset in progress during close, FW reset will be aborted
  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
  ...
  Process ethtool (pid: 333327, stack limit = 0x0000000046476577)
  Call trace:
  bnxt_alloc_mem+0x444/0xef0 [bnxt_en]
  bnxt_half_open_nic+0x24/0xb8 [bnxt_en]
  bnxt_self_test+0x2dc/0x390 [bnxt_en]
  ethtool_self_test+0xe0/0x1f8
  dev_ethtool+0x1744/0x22d0
  dev_ioctl+0x190/0x3e0
  sock_ioctl+0x238/0x480
  do_vfs_ioctl+0xc4/0x758
  ksys_ioctl+0x84/0xb8
  __arm64_sys_ioctl+0x28/0x38
  el0_svc_handler+0xb0/0x180
  el0_svc+0x8/0xc

Fixes: a1301f08c5ac ("bnxt_en: Check abort error state in bnxt_open_nic().")
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 169f093e01de..31eb3c00851a 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -10208,6 +10208,12 @@ int bnxt_half_open_nic(struct bnxt *bp)
 {
 	int rc = 0;
 
+	if (test_bit(BNXT_STATE_ABORT_ERR, &bp->state)) {
+		netdev_err(bp->dev, "A previous firmware reset has not completed, aborting half open\n");
+		rc = -ENODEV;
+		goto half_open_err;
+	}
+
 	rc = bnxt_alloc_mem(bp, false);
 	if (rc) {
 		netdev_err(bp->dev, "bnxt_alloc_mem err: %x\n", rc);
-- 
2.18.1


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