Hello Helmut Schaa,
I'm going through some old static checker warnings and I was concerned
about this one:
The patch 55b585e29095: "rt2x00: Don't call ieee80211_get_tx_rate for
MCS rates" from Mar 3, 2011, leads to the following warning:
drivers/net/wireless/rt2x00/rt2x00queue.c:508
rt2x00queue_create_tx_descriptor()
error: potential NULL dereference 'hwrate'.
482 /*
483 * Determine rate modulation.
484 */
485 if (txrate->flags & IEEE80211_TX_RC_GREEN_FIELD)
486 txdesc->rate_mode = RATE_MODE_HT_GREENFIELD;
hwrate is NULL here.
487 else if (txrate->flags & IEEE80211_TX_RC_MCS)
488 txdesc->rate_mode = RATE_MODE_HT_MIX;
489 else {
490 rate = ieee80211_get_tx_rate(rt2x00dev->hw, tx_info);
491 hwrate = rt2x00_get_rate(rate->hw_value);
492 if (hwrate->flags & DEV_RATE_OFDM)
493 txdesc->rate_mode = RATE_MODE_OFDM;
494 else
495 txdesc->rate_mode = RATE_MODE_CCK;
496 }
497
498 /*
499 * Apply TX descriptor handling by components
500 */
501 rt2x00crypto_create_tx_descriptor(rt2x00dev, skb, txdesc);
502 rt2x00queue_create_tx_descriptor_seq(rt2x00dev, skb, txdesc);
503
504 if (test_bit(REQUIRE_HT_TX_DESC, &rt2x00dev->cap_flags))
505 rt2x00queue_create_tx_descriptor_ht(rt2x00dev, skb, txdesc,
506 hwrate);
On this path we dereference dereference hwrate if IEEE80211_TX_RC_MCS is
not set, but we don't check for IEEE80211_TX_RC_GREEN_FIELD.
507 else
508 rt2x00queue_create_tx_descriptor_plcp(rt2x00dev, skb, txdesc,
509 hwrate);
On this patch we dereference hwrate unconditionally.
regards,
dan carpenter
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