Thread (5 messages) 5 messages, 2 authors, 2021-12-29

Re: [PATCH] mac80211: initialize variable have_higher_than_11mbit

From: Nick Desaulniers <hidden>
Date: 2021-12-23 20:30:18
Also in: lkml, llvm, netdev

On Thu, Dec 23, 2021 at 8:29 AM [off-list ref] wrote:
From: Tom Rix <trix@redhat.com>

Clang static analysis reports this warnings

mlme.c:5332:7: warning: Branch condition evaluates to a
  garbage value
    have_higher_than_11mbit)
    ^~~~~~~~~~~~~~~~~~~~~~~

have_higher_than_11mbit is only set to true some of the time in
ieee80211_get_rates() but is checked all of the time.  So
have_higher_than_11mbit needs to be initialized to false.
LGTM. There's only one caller of ieee80211_get_rates() today; if there
were others, they could make a similar mistake in the future. An
alternate approach: ieee80211_get_rates() could unconditionally write
false before the loop that could later write true. Then call sites
don't need to worry about this conditional assignment. Perhaps that
would be preferable? If not:

Reviewed-by: Nick Desaulniers <redacted>
quoted hunk ↗ jump to hunk
Fixes: 5d6a1b069b7f ("mac80211: set basic rates earlier")
Signed-off-by: Tom Rix <trix@redhat.com>
---
 net/mac80211/mlme.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 51f55c4ee3c6e..766cbbc9c3a72 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -5279,7 +5279,7 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata,
         */
        if (new_sta) {
                u32 rates = 0, basic_rates = 0;
-               bool have_higher_than_11mbit;
+               bool have_higher_than_11mbit = false;
                int min_rate = INT_MAX, min_rate_index = -1;
                const struct cfg80211_bss_ies *ies;
                int shift = ieee80211_vif_get_shift(&sdata->vif);
--
2.26.3

-- 
Thanks,
~Nick Desaulniers
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