Thread (51 messages) 51 messages, 12 authors, 2020-06-15

Re: [PATCH 04/10] rtlwifi: rtl8192cu: Remove uninitialized_var() usage

From: Nick Desaulniers <hidden>
Date: 2020-06-04 20:16:29
Also in: linux-block, linux-clk, linux-mm, linux-spi, linux-wireless, lkml, netdev

On Wed, Jun 3, 2020 at 4:32 PM Kees Cook [off-list ref] wrote:
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings (e.g.
"unused variable"). If the compiler thinks it is uninitialized, either
simply initialize the variable or make compiler changes. As a precursor
to removing[2] this[3] macro[4], just initialize this variable to NULL,
and avoid sending garbage by returning.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ (local)
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ (local)
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ (local)
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ (local)

Signed-off-by: Kees Cook <redacted>
Reviewed-by: Nick Desaulniers <redacted>
Fixes: dc0313f46664 ("rtlwifi: rtl8192cu: Add routine hw")
quoted hunk ↗ jump to hunk
---
 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
index f070f25bb735..5b071b70bc08 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
@@ -592,7 +592,7 @@ static void _rtl92cu_init_chipn_one_out_ep_priority(struct ieee80211_hw *hw,
                                                    bool wmm_enable,
                                                    u8 queue_sel)
 {
-       u16 uninitialized_var(value);
+       u16 value;

        switch (queue_sel) {
        case TX_SELE_HQ:
@@ -606,7 +606,7 @@ static void _rtl92cu_init_chipn_one_out_ep_priority(struct ieee80211_hw *hw,
                break;
        default:
                WARN_ON(1); /* Shall not reach here! */
-               break;
+               return;
        }
        _rtl92c_init_chipn_reg_priority(hw, value, value, value, value,
                                        value, value);
Whew! Nothing like passing the same value 6 times! (Other callers do
use distinct values though, just curious seeing this instance.)

-- 
Thanks,
~Nick Desaulniers
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