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Date: Thu, 9 May 2024 16:24:39 +0300
From: Dan Carpenter <dan.carpenter@linaro.org>
To: alexis.lothore@bootlin.com
Cc: linux-wireless@vger.kernel.org
Subject: [bug report] wifi: wilc1000: convert list management to RCU
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Hello Alexis Lothor?,

Commit f236464f1db7 ("wifi: wilc1000: convert list management to
RCU") from Apr 10, 2024 (linux-next), leads to the following Smatch
static checker warning:

	drivers/net/wireless/microchip/wilc1000/mon.c:236 wilc_wfi_init_mon_interface()
	warn: sleeping in atomic context

The problem is in the caller:

drivers/net/wireless/microchip/wilc1000/cfg80211.c
  1527  static struct wireless_dev *add_virtual_intf(struct wiphy *wiphy,
  1528                                               const char *name,
  1529                                               unsigned char name_assign_type,
  1530                                               enum nl80211_iftype type,
  1531                                               struct vif_params *params)
  1532  {
  1533          struct wilc *wl = wiphy_priv(wiphy);
  1534          struct wilc_vif *vif;
  1535          struct wireless_dev *wdev;
  1536          int iftype;
  1537  
  1538          if (type == NL80211_IFTYPE_MONITOR) {
  1539                  struct net_device *ndev;
  1540  
  1541                  rcu_read_lock();
                        ^^^^^^^^^^^^^^^
The patch changes this to disable preemption.

  1542                  vif = wilc_get_vif_from_type(wl, WILC_AP_MODE);
  1543                  if (!vif) {
  1544                          vif = wilc_get_vif_from_type(wl, WILC_GO_MODE);
  1545                          if (!vif) {
  1546                                  rcu_read_unlock();
  1547                                  goto validate_interface;
  1548                          }
  1549                  }
  1550  
  1551                  if (vif->monitor_flag) {
  1552                          rcu_read_unlock();
  1553                          goto validate_interface;
  1554                  }
  1555  
  1556                  ndev = wilc_wfi_init_mon_interface(wl, name, vif->ndev);
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Does a few sleeping allocations.

  1557                  if (ndev) {
  1558                          vif->monitor_flag = 1;
  1559                  } else {
  1560                          rcu_read_unlock();
  1561                          return ERR_PTR(-EINVAL);
  1562                  }
  1563  
  1564                  wdev = &vif->priv.wdev;
  1565                  rcu_read_unlock();
  1566                  return wdev;
  1567          }

regards,
dan carpenter