From: Dan Carpenter <dan.carpenter@oracle.com>
To: helmut.schaa@googlemail.com
Cc: linux-wireless@vger.kernel.org
Subject: re: rt2x00: Don't call ieee80211_get_tx_rate for MCS rates
Date: Thu, 19 Jul 2012 14:33:08 +0300 [thread overview]
Message-ID: <20120719113308.GA32491@elgon.mountain> (raw)
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
next reply other threads:[~2012-07-19 11:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-19 11:33 Dan Carpenter [this message]
2012-07-19 11:46 ` rt2x00: Don't call ieee80211_get_tx_rate for MCS rates Helmut Schaa
2012-07-20 7:28 ` Dan Carpenter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120719113308.GA32491@elgon.mountain \
--to=dan.carpenter@oracle.com \
--cc=helmut.schaa@googlemail.com \
--cc=linux-wireless@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).