Re: rtlwifi: rtl8192c_common: "BUG: KASAN: slab-out-of-bounds"

Larry Finger
2017-02-05T17:30:35Z

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On 02/05/2017 05:34 AM, Dmitry Osipenko wrote:
> BTW, I have an issue with the 8192cu: WiFi stops to work after a while (3-15
> minutes) if I enable WMM QoS on the AP. There is nothing suspicious in KMSG,
> connection is up but no packets go in/out. I tried to enable debug messages in
> the driver, so when the WiFi stops to work I see that some "temperature/led"
> notify still going on in the driver, but nothing happens when I try to initiate
> a transfer (say to open a web page) - the log is silent, like the requests are
> getting stuck/dropped somewhere before reaching the driver. Is it a known issue?
> With the QoS disabled everything works hunky-dory, however I get 2x-4x faster
> download speed with QoS enabled (while it works.)
>
> I noticed that rtl92c_init_edca_param() isn't wired in the driver, so I suppose
> the QoS isn't implemented yet, right?
>
> If it is an expected behaviour, I think at least printing a warning message in
> the KMSG like "QoS unimplemented, you may expect problems" should be good enough
> to avoid confusion.

As you have already seen, I decided to defer the more invasive patch. When
backporting to stable, the smaller the change the better.

I have no knowledge of the internals of the RTL8192CU chip. As a result, the
kinds of changes I can make are limited. I do know that the chip does implement
QoS. I also noticed that the set_qos() callback routine was very different in
rtl8192ce than in rtl8192cu. Attached is an untested patch to make the CU
routine look like the CE version. Please see if it makes a difference.

Driver rtl8192cu has never been maintained by Realtek, and it will likely be
removed from the kernel in the next few cycles. As you are running a new kernel,
I would recommend rtl8xxxu instead. That driver has high reliability, and the
speed is improving. Your other option would be a driver offered by the vendor of
your particular device. Realtek used to have these drivers on their web site,
but they now seem to have been removed. If your vendor does not have a driver,
http://www.edimax.com/edimax/mw/cufiles/files/download/Driver_Utility/transfer/Wireless/NIC/EW-7811Un/EW-7811Un_Linux_driver_v1.0.0.5.zip
should work.

Larry

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diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c
index 1b124ea..1fcf570 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c
@@ -387,7 +387,23 @@ void rtl92c_set_qos(struct ieee80211_hw *hw, int aci)
struct rtl_priv *rtlpriv = rtl_priv(hw);

rtl92c_dm_init_edca_turbo(hw);
- rtlpriv->cfg->ops->set_hw_reg(hw, HW_VAR_AC_PARAM, (u8 *)&aci);
+ switch (aci) {
+ case AC1_BK:
+ rtl_write_dword(rtlpriv, REG_EDCA_BK_PARAM, 0xa44f);
+ break;
+ case AC0_BE:
+ /* rtl_write_dword(rtlpriv, REG_EDCA_BE_PARAM, u4b_ac_param); */
+ break;
+ case AC2_VI:
+ rtl_write_dword(rtlpriv, REG_EDCA_VI_PARAM, 0x5e4322);
+ break;
+ case AC3_VO:
+ rtl_write_dword(rtlpriv, REG_EDCA_VO_PARAM, 0x2f3222);
+ break;
+ default:
+ WARN_ONCE(true, "rtl8192ce: invalid aci: %d !\n", aci);
+ break;
+ }
}

void rtl92c_init_driver_info_size(struct ieee80211_hw *hw, u8 size)