Hi Dan,
The offending patch that caused the Smatch complaint is:
"iwlwifi: mvm: add explicit check for non-data frames in get Tx rate"
this patch adds an unconditional dereference of the sta parameter in iwl_mvm_get_tx_rate().
Before that, all the code paths check for the NULL option.
(this patch is from the recent days, that's why Smatch only complains now).
Regards,
Avi
-----Original Message-----
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Sent: Wednesday, February 10, 2021 12:55
To: Stern, Avraham <avraham.stern@xxxxxxxxx>
Cc: linux-wireless@xxxxxxxxxxxxxxx
Subject: [bug report] iwlwifi: mvm: toggle tx antenna if tx fails during connection establishment
[ Sorry, I don't know why Smatch is warning about a three year old bug
and I'm not sure that it's blaming the correct commit but the warning
looks correct. - dan ]
Hello Avraham Stern,
This is a semi-automatic email about new static checker warnings.
The patch 0dde2440a77f: "iwlwifi: mvm: toggle tx antenna if tx fails during connection establishment" from Jul 11, 2018, leads to the following Smatch complaint:
drivers/net/wireless/intel/iwlwifi/mvm/tx.c:356 iwl_mvm_set_tx_cmd_rate()
error: we previously assumed 'sta' could be null (see line 341)
drivers/net/wireless/intel/iwlwifi/mvm/tx.c
340
341 if (ieee80211_is_data(fc) && sta) {
^^^ This assumes that "sta" can be NULL.
342 struct iwl_mvm_sta *mvmsta = iwl_mvm_sta_from_mac80211(sta);
343
344 if (mvmsta->sta_state >= IEEE80211_STA_AUTHORIZED) {
345 tx_cmd->initial_rate_index = 0;
346 tx_cmd->tx_flags |= cpu_to_le32(TX_CMD_FLG_STA_RATE);
347 return;
348 }
349 } else if (ieee80211_is_back_req(fc)) {
350 tx_cmd->tx_flags |=
351 cpu_to_le32(TX_CMD_FLG_ACK | TX_CMD_FLG_BAR);
352 }
353
354 /* Set the rate in the TX cmd */
355 tx_cmd->rate_n_flags =
356 cpu_to_le32(iwl_mvm_get_tx_rate_n_flags(mvm, info, sta, fc));
^^^ It is dereferenced unconsiditionally inside the function.
357 }
358
See also:
drivers/net/wireless/intel/iwlwifi/mvm/tx.c:486 iwl_mvm_set_tx_params() error: we previously assumed 'sta' could be null (see line 482)
regards,
dan carpenter
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