From 154d4899e4111ae24e68d6ba955f46856cb046bc Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 30 Mar 2019 10:31:52 +0100 Subject: iwlwifi: mvm: properly check debugfs dentry before using it debugfs can now report an error code if something went wrong instead of just NULL. So if the return value is to be used as a "real" dentry, it needs to be checked if it is an error before dereferencing it. This is now happening because of ff9fb72bc077 ("debugfs: return error values, not NULL"). If multiple iwlwifi devices are in the system, this can cause problems when the driver attempts to create the main debugfs directory again. Later on in the code we fail horribly by trying to dereference a pointer that is an error value. Reported-by: Laura Abbott Reported-by: Gabriel Ramirez Cc: Johannes Berg Cc: Emmanuel Grumbach Cc: Luca Coelho Cc: Intel Linux Wireless Cc: Kalle Valo Cc: stable # 5.0 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Luca Coelho --- drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c index 2453ceabf00d..738eddb2e7ac 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c @@ -774,6 +774,11 @@ void iwl_mvm_vif_dbgfs_register(struct iwl_mvm *mvm, struct ieee80211_vif *vif) return; mvmvif->dbgfs_dir = debugfs_create_dir("iwlmvm", dbgfs_dir); + if (IS_ERR_OR_NULL(mvmvif->dbgfs_dir)) { + IWL_ERR(mvm, "Failed to create debugfs directory under %pd\n", + dbgfs_dir); + return; + } if (!mvmvif->dbgfs_dir) { IWL_ERR(mvm, "Failed to create debugfs directory under %pd\n", -- cgit v1.2.3