gcc-8 points out that source and destination of the memcpy() are
always the same pointer, so the effect of memcpy() is undefined
here (its arguments must not overlap):
drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c: In function '_rtl_rx_process':
drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c:430:2: error: 'memcpy' source argument is the same as destination [-Werror=restrict]
Most likely this is harmless, but it's easy to just remove the
line and get rid of the warning.
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
index ac4a82de40c7..9ab56827124e 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
@@ -427,7 +427,6 @@ static void _rtl_rx_process(struct ieee80211_hw *hw, struct sk_buff *skb)
(u32)hdr->addr1[0], (u32)hdr->addr1[1],
(u32)hdr->addr1[2], (u32)hdr->addr1[3],
(u32)hdr->addr1[4], (u32)hdr->addr1[5]);
- memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
ieee80211_rx(hw, skb);
}
--
2.9.0
On Fri, 2018-02-09 at 14:24 +0100, Arnd Bergmann wrote:
> gcc-8 points out that source and destination of the memcpy() are
> always the same pointer, so the effect of memcpy() is undefined
> here (its arguments must not overlap):
>
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c: In function '_rtl_rx_process':
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c:430:2: error: 'memcpy' source argument is the same as destination [-Werror=restrict]
>
> Most likely this is harmless, but it's easy to just remove the
> line and get rid of the warning.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> index ac4a82de40c7..9ab56827124e 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> @@ -427,7 +427,6 @@ static void _rtl_rx_process(struct ieee80211_hw *hw, struct sk_buff *skb)
> (u32)hdr->addr1[0], (u32)hdr->addr1[1],
> (u32)hdr->addr1[2], (u32)hdr->addr1[3],
> (u32)hdr->addr1[4], (u32)hdr->addr1[5]);
> - memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
> ieee80211_rx(hw, skb);
> }
trivia:
The RT_TRACE above this should probably use %pM too.
Not submitted as it would just cause a conflict.
---
drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
index ac4a82de40c7..61da667ed8ba 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
@@ -422,11 +422,8 @@ static void _rtl_rx_process(struct ieee80211_hw *hw, struct sk_buff *skb)
if (ieee80211_is_data(fc))
RT_TRACE(rtlpriv, COMP_INIT, DBG_DMESG, "Got data frame\n");
RT_TRACE(rtlpriv, COMP_INIT, DBG_DMESG,
- "Fram: fc = 0x%X addr1 = 0x%02X:0x%02X:0x%02X:0x%02X:0x%02X:0x%02X\n",
- fc,
- (u32)hdr->addr1[0], (u32)hdr->addr1[1],
- (u32)hdr->addr1[2], (u32)hdr->addr1[3],
- (u32)hdr->addr1[4], (u32)hdr->addr1[5]);
+ "Fram: fc = 0x%X addr1 = %pM\n",
+ fc, hdr->addr1);
memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
ieee80211_rx(hw, skb);
}
On 02/09/2018 07:24 AM, Arnd Bergmann wrote:
> gcc-8 points out that source and destination of the memcpy() are
> always the same pointer, so the effect of memcpy() is undefined
> here (its arguments must not overlap):
>
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c: In function '_rtl_rx_process':
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c:430:2: error: 'memcpy' source argument is the same as destination [-Werror=restrict]
>
> Most likely this is harmless, but it's easy to just remove the
> line and get rid of the warning.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> index ac4a82de40c7..9ab56827124e 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> @@ -427,7 +427,6 @@ static void _rtl_rx_process(struct ieee80211_hw *hw, struct sk_buff *skb)
> (u32)hdr->addr1[0], (u32)hdr->addr1[1],
> (u32)hdr->addr1[2], (u32)hdr->addr1[3],
> (u32)hdr->addr1[4], (u32)hdr->addr1[5]);
> - memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
> ieee80211_rx(hw, skb);
> }
No, the warning is pointing to the wrong place. The routine in question does the
following:
1. Loads the rx_status struct from skb->cb.
2. Overwrites the contents with 0.
3. Fills various members of the struct.
4. Writes the revised struct back into skb->cb.
Thus eliminating step 4 negates all the things done in step 3, and is wrong. The
correct fix is to change step 1 to create a NULL-filled rx_status struct, and
eliminate step 2.
NACK.
Larry
On 02/09/2018 07:24 AM, Arnd Bergmann wrote:
> gcc-8 points out that source and destination of the memcpy() are
> always the same pointer, so the effect of memcpy() is undefined
> here (its arguments must not overlap):
>
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c: In function '_rtl_rx_process':
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c:430:2: error: 'memcpy' source argument is the same as destination [-Werror=restrict]
>
> Most likely this is harmless, but it's easy to just remove the
> line and get rid of the warning.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> index ac4a82de40c7..9ab56827124e 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
> @@ -427,7 +427,6 @@ static void _rtl_rx_process(struct ieee80211_hw *hw, struct sk_buff *skb)
> (u32)hdr->addr1[0], (u32)hdr->addr1[1],
> (u32)hdr->addr1[2], (u32)hdr->addr1[3],
> (u32)hdr->addr1[4], (u32)hdr->addr1[5]);
> - memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
> ieee80211_rx(hw, skb);
> }
Argh. Once again I got tripped up on pointers. Yes, this patch is correct.
Acked-by: Larry Finger <[email protected]>
Sorry about the noise.
Larry
Arnd Bergmann <[email protected]> wrote:
> gcc-8 points out that source and destination of the memcpy() are
> always the same pointer, so the effect of memcpy() is undefined
> here (its arguments must not overlap):
>
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c: In function '_rtl_rx_process':
> drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c:430:2: error: 'memcpy' source argument is the same as destination [-Werror=restrict]
>
> Most likely this is harmless, but it's easy to just remove the
> line and get rid of the warning.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> Acked-by: Larry Finger <[email protected]>
Patch applied to wireless-drivers-next.git, thanks.
dcdd54c2bcae rtlwifi: rtl8192cu: remove pointless memcpy
--
https://patchwork.kernel.org/patch/10208979/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches