* [PATCH] staging: Replace zero-length array with flexible-array member
@ 2020-02-20 13:29 ` Gustavo A. R. Silva
0 siblings, 0 replies; 6+ messages in thread
From: Gustavo A. R. Silva @ 2020-02-20 13:29 UTC (permalink / raw)
To: Greg Kroah-Hartman, Vaibhav Agarwal, Mark Greer, Johan Hovold,
Alex Elder, Michael Tretter, Pengutronix Kernel Team,
Mauro Carvalho Chehab, Larry Finger, Florian Schilhabel,
Adham Abozaeid, Ajay Singh
Cc: devel, linux-kernel, greybus-dev, linux-media, linux-wireless,
Gustavo A. R. Silva
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/staging/gdm724x/gdm_mux.h | 2 +-
drivers/staging/gdm724x/hci_packet.h | 6 ++--
drivers/staging/greybus/audio_apbridgea.h | 2 +-
drivers/staging/ks7010/ks_hostif.h | 4 +--
.../staging/media/allegro-dvt/allegro-core.c | 2 +-
drivers/staging/octeon-usb/octeon-hcd.c | 2 +-
drivers/staging/rtl8192e/rtllib.h | 30 +++++++++----------
.../staging/rtl8192u/ieee80211/ieee80211.h | 28 ++++++++---------
drivers/staging/rtl8712/ieee80211.h | 4 +--
drivers/staging/rtl8712/rtl871x_mp_ioctl.h | 4 +--
drivers/staging/wilc1000/cfg80211.c | 10 +++----
drivers/staging/wilc1000/spi.c | 2 +-
drivers/staging/wlan-ng/hfa384x.h | 4 +--
drivers/staging/wlan-ng/p80211types.h | 4 +--
14 files changed, 52 insertions(+), 52 deletions(-)
diff --git a/drivers/staging/gdm724x/gdm_mux.h b/drivers/staging/gdm724x/gdm_mux.h
index 51c22e3d8aeb..87b8d921fdc8 100644
--- a/drivers/staging/gdm724x/gdm_mux.h
+++ b/drivers/staging/gdm724x/gdm_mux.h
@@ -29,7 +29,7 @@ struct mux_pkt_header {
__le32 seq_num;
__le32 payload_size;
__le16 packet_type;
- unsigned char data[0];
+ unsigned char data[];
};
struct mux_tx {
diff --git a/drivers/staging/gdm724x/hci_packet.h b/drivers/staging/gdm724x/hci_packet.h
index 6dea3694afdd..faecdfbc664f 100644
--- a/drivers/staging/gdm724x/hci_packet.h
+++ b/drivers/staging/gdm724x/hci_packet.h
@@ -28,7 +28,7 @@
struct hci_packet {
__dev16 cmd_evt;
__dev16 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct tlv {
@@ -51,7 +51,7 @@ struct sdu {
__dev32 dft_eps_ID;
__dev32 bearer_ID;
__dev32 nic_type;
- u8 data[0];
+ u8 data[];
} __packed;
struct multi_sdu {
@@ -59,7 +59,7 @@ struct multi_sdu {
__dev16 len;
__dev16 num_packet;
__dev16 reserved;
- u8 data[0];
+ u8 data[];
} __packed;
struct hci_pdn_table_ind {
diff --git a/drivers/staging/greybus/audio_apbridgea.h b/drivers/staging/greybus/audio_apbridgea.h
index 3f1f4dd2c61a..efec0f815efd 100644
--- a/drivers/staging/greybus/audio_apbridgea.h
+++ b/drivers/staging/greybus/audio_apbridgea.h
@@ -65,7 +65,7 @@
struct audio_apbridgea_hdr {
__u8 type;
__le16 i2s_port;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct audio_apbridgea_set_config_request {
diff --git a/drivers/staging/ks7010/ks_hostif.h b/drivers/staging/ks7010/ks_hostif.h
index ca7dc8f5166c..39138191a556 100644
--- a/drivers/staging/ks7010/ks_hostif.h
+++ b/drivers/staging/ks7010/ks_hostif.h
@@ -70,7 +70,7 @@ struct hostif_data_request {
#define TYPE_DATA 0x0000
#define TYPE_AUTH 0x0001
__le16 reserved;
- u8 data[0];
+ u8 data[];
} __packed;
#define TYPE_PMK1 0x0001
@@ -194,7 +194,7 @@ enum mib_data_type {
struct hostif_mib_value {
__le16 size;
__le16 type;
- u8 body[0];
+ u8 body[];
} __packed;
struct hostif_mib_get_confirm_t {
diff --git a/drivers/staging/media/allegro-dvt/allegro-core.c b/drivers/staging/media/allegro-dvt/allegro-core.c
index 3be41698df4c..0a09b3622e78 100644
--- a/drivers/staging/media/allegro-dvt/allegro-core.c
+++ b/drivers/staging/media/allegro-dvt/allegro-core.c
@@ -434,7 +434,7 @@ struct mcu_msg_push_buffers_internal_buffer {
struct mcu_msg_push_buffers_internal {
struct mcu_msg_header header;
u32 channel_id;
- struct mcu_msg_push_buffers_internal_buffer buffer[0];
+ struct mcu_msg_push_buffers_internal_buffer buffer[];
} __attribute__ ((__packed__));
struct mcu_msg_put_stream_buffer {
diff --git a/drivers/staging/octeon-usb/octeon-hcd.c b/drivers/staging/octeon-usb/octeon-hcd.c
index 582c9187559d..61471a19d4e6 100644
--- a/drivers/staging/octeon-usb/octeon-hcd.c
+++ b/drivers/staging/octeon-usb/octeon-hcd.c
@@ -406,7 +406,7 @@ struct octeon_hcd {
*/
struct octeon_temp_buffer {
void *orig_buffer;
- u8 data[0];
+ u8 data[];
};
static inline struct usb_hcd *octeon_to_hcd(struct octeon_hcd *p)
diff --git a/drivers/staging/rtl8192e/rtllib.h b/drivers/staging/rtl8192e/rtllib.h
index 328f410daa03..b84f00b8d18b 100644
--- a/drivers/staging/rtl8192e/rtllib.h
+++ b/drivers/staging/rtl8192e/rtllib.h
@@ -728,14 +728,14 @@ struct rtllib_pspoll_hdr {
struct rtllib_hdr {
__le16 frame_ctl;
__le16 duration_id;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_1addr {
__le16 frame_ctl;
__le16 duration_id;
u8 addr1[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_2addr {
@@ -743,7 +743,7 @@ struct rtllib_hdr_2addr {
__le16 duration_id;
u8 addr1[ETH_ALEN];
u8 addr2[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_3addr {
@@ -753,7 +753,7 @@ struct rtllib_hdr_3addr {
u8 addr2[ETH_ALEN];
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_4addr {
@@ -764,7 +764,7 @@ struct rtllib_hdr_4addr {
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
u8 addr4[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_3addrqos {
@@ -775,7 +775,7 @@ struct rtllib_hdr_3addrqos {
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
__le16 qos_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_4addrqos {
@@ -787,13 +787,13 @@ struct rtllib_hdr_4addrqos {
__le16 seq_ctl;
u8 addr4[ETH_ALEN];
__le16 qos_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_info_element {
u8 id;
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct rtllib_authentication {
@@ -802,7 +802,7 @@ struct rtllib_authentication {
__le16 transaction;
__le16 status;
/*challenge*/
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
struct rtllib_disauth {
@@ -818,7 +818,7 @@ struct rtllib_disassoc {
struct rtllib_probe_request {
struct rtllib_hdr_3addr header;
/* SSID, supported rates */
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
struct rtllib_probe_response {
@@ -829,7 +829,7 @@ struct rtllib_probe_response {
/* SSID, supported rates, FH params, DS params,
* CF params, IBSS params, TIM (if beacon), RSN
*/
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
/* Alias beacon for probe_response */
@@ -840,7 +840,7 @@ struct rtllib_assoc_request_frame {
__le16 capability;
__le16 listen_interval;
/* SSID, supported rates, RSN */
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
struct rtllib_assoc_response_frame {
@@ -848,7 +848,7 @@ struct rtllib_assoc_response_frame {
__le16 capability;
__le16 status;
__le16 aid;
- struct rtllib_info_element info_element[0]; /* supported rates */
+ struct rtllib_info_element info_element[]; /* supported rates */
} __packed;
struct rtllib_txb {
@@ -859,7 +859,7 @@ struct rtllib_txb {
u16 reserved;
__le16 frag_size;
__le16 payload_size;
- struct sk_buff *fragments[0];
+ struct sk_buff *fragments[];
};
#define MAX_SUBFRAME_COUNT 64
@@ -1792,7 +1792,7 @@ struct rtllib_device {
/* This must be the last item so that it points to the data
* allocated beyond this structure by alloc_rtllib
*/
- u8 priv[0];
+ u8 priv[];
};
#define IEEE_A (1<<0)
diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211.h b/drivers/staging/rtl8192u/ieee80211/ieee80211.h
index 9576b647f6b1..39f4ddd86796 100644
--- a/drivers/staging/rtl8192u/ieee80211/ieee80211.h
+++ b/drivers/staging/rtl8192u/ieee80211/ieee80211.h
@@ -886,14 +886,14 @@ enum ieee80211_mfie {
struct rtl_80211_hdr {
__le16 frame_ctl;
__le16 duration_id;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_1addr {
__le16 frame_ctl;
__le16 duration_id;
u8 addr1[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_2addr {
@@ -901,7 +901,7 @@ struct rtl_80211_hdr_2addr {
__le16 duration_id;
u8 addr1[ETH_ALEN];
u8 addr2[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_3addr {
@@ -911,7 +911,7 @@ struct rtl_80211_hdr_3addr {
u8 addr2[ETH_ALEN];
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_4addr {
@@ -922,7 +922,7 @@ struct rtl_80211_hdr_4addr {
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
u8 addr4[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_3addrqos {
@@ -951,7 +951,7 @@ struct rtl_80211_hdr_4addrqos {
struct ieee80211_info_element {
u8 id;
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct ieee80211_authentication {
@@ -960,7 +960,7 @@ struct ieee80211_authentication {
__le16 transaction;
__le16 status;
/*challenge*/
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_disassoc {
@@ -971,7 +971,7 @@ struct ieee80211_disassoc {
struct ieee80211_probe_request {
struct rtl_80211_hdr_3addr header;
/* SSID, supported rates */
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_probe_response {
@@ -982,7 +982,7 @@ struct ieee80211_probe_response {
/* SSID, supported rates, FH params, DS params,
* CF params, IBSS params, TIM (if beacon), RSN
*/
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
/* Alias beacon for probe_response */
@@ -993,7 +993,7 @@ struct ieee80211_assoc_request_frame {
__le16 capability;
__le16 listen_interval;
/* SSID, supported rates, RSN */
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_reassoc_request_frame {
@@ -1002,7 +1002,7 @@ struct ieee80211_reassoc_request_frame {
__le16 listen_interval;
u8 current_ap[ETH_ALEN];
/* SSID, supported rates, RSN */
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_assoc_response_frame {
@@ -1010,7 +1010,7 @@ struct ieee80211_assoc_response_frame {
__le16 capability;
__le16 status;
__le16 aid;
- struct ieee80211_info_element info_element[0]; /* supported rates */
+ struct ieee80211_info_element info_element[]; /* supported rates */
} __packed;
struct ieee80211_txb {
@@ -1021,7 +1021,7 @@ struct ieee80211_txb {
u16 reserved;
__le16 frag_size;
__le16 payload_size;
- struct sk_buff *fragments[0];
+ struct sk_buff *fragments[];
};
#define MAX_TX_AGG_COUNT 16
@@ -2007,7 +2007,7 @@ struct ieee80211_device {
/* This must be the last item so that it points to the data
* allocated beyond this structure by alloc_ieee80211
*/
- u8 priv[0];
+ u8 priv[];
};
#define IEEE_A (1<<0)
diff --git a/drivers/staging/rtl8712/ieee80211.h b/drivers/staging/rtl8712/ieee80211.h
index 8098f6905554..dabaa8fd34fb 100644
--- a/drivers/staging/rtl8712/ieee80211.h
+++ b/drivers/staging/rtl8712/ieee80211.h
@@ -535,7 +535,7 @@ struct ieee80211_info_element_hdr {
struct ieee80211_info_element {
u8 id;
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
/*
@@ -597,7 +597,7 @@ struct ieee80211_txb {
u16 reserved;
u16 frag_size;
u16 payload_size;
- struct sk_buff *fragments[0];
+ struct sk_buff *fragments[];
};
/* SWEEP TABLE ENTRIES NUMBER*/
diff --git a/drivers/staging/rtl8712/rtl871x_mp_ioctl.h b/drivers/staging/rtl8712/rtl871x_mp_ioctl.h
index 64e2ae436625..59fa6664d868 100644
--- a/drivers/staging/rtl8712/rtl871x_mp_ioctl.h
+++ b/drivers/staging/rtl8712/rtl871x_mp_ioctl.h
@@ -48,7 +48,7 @@ struct eeprom_rw_param {
struct EFUSE_ACCESS_STRUCT {
u16 start_addr;
u16 cnts;
- u8 data[0];
+ u8 data[];
};
struct burst_rw_reg {
@@ -324,7 +324,7 @@ struct mp_ioctl_handler {
struct mp_ioctl_param {
unsigned int subcode;
unsigned int len;
- unsigned char data[0];
+ unsigned char data[];
};
#define GEN_MP_IOCTL_SUBCODE(code) _MP_IOCTL_ ## code ## _CMD_
diff --git a/drivers/staging/wilc1000/cfg80211.c b/drivers/staging/wilc1000/cfg80211.c
index 995b1f306807..5d8faa01337d 100644
--- a/drivers/staging/wilc1000/cfg80211.c
+++ b/drivers/staging/wilc1000/cfg80211.c
@@ -62,7 +62,7 @@ struct wilc_p2p_pub_act_frame {
u8 oui_type;
u8 oui_subtype;
u8 dialog_token;
- u8 elem[0];
+ u8 elem[];
} __packed;
struct wilc_vendor_specific_ie {
@@ -70,13 +70,13 @@ struct wilc_vendor_specific_ie {
u8 tag_len;
u8 oui[3];
u8 oui_type;
- u8 attr[0];
+ u8 attr[];
} __packed;
struct wilc_attr_entry {
u8 attr_type;
__le16 attr_len;
- u8 val[0];
+ u8 val[];
} __packed;
struct wilc_attr_oper_ch {
@@ -91,13 +91,13 @@ struct wilc_attr_ch_list {
u8 attr_type;
__le16 attr_len;
u8 country_code[IEEE80211_COUNTRY_STRING_LEN];
- u8 elem[0];
+ u8 elem[];
} __packed;
struct wilc_ch_list_elem {
u8 op_class;
u8 no_of_channels;
- u8 ch_list[0];
+ u8 ch_list[];
} __packed;
static void cfg_scan_result(enum scan_event scan_event,
diff --git a/drivers/staging/wilc1000/spi.c b/drivers/staging/wilc1000/spi.c
index 44f7d48851b5..11653ac118cd 100644
--- a/drivers/staging/wilc1000/spi.c
+++ b/drivers/staging/wilc1000/spi.c
@@ -139,7 +139,7 @@ struct wilc_spi_read_rsp_data {
u8 status;
u8 resp_header;
u8 resp_data[4];
- u8 crc[0];
+ u8 crc[];
} __packed;
struct wilc_spi_rsp_data {
diff --git a/drivers/staging/wlan-ng/hfa384x.h b/drivers/staging/wlan-ng/hfa384x.h
index bdd7f414fdbb..88e894dd3568 100644
--- a/drivers/staging/wlan-ng/hfa384x.h
+++ b/drivers/staging/wlan-ng/hfa384x.h
@@ -355,7 +355,7 @@
/* Commonly used basic types */
struct hfa384x_bytestr {
__le16 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct hfa384x_bytestr32 {
@@ -421,7 +421,7 @@ struct hfa384x_authenticate_station_data {
/*-- Configuration Record: WPAData (data portion only) --*/
struct hfa384x_wpa_data {
__le16 datalen;
- u8 data[0]; /* max 80 */
+ u8 data[]; /* max 80 */
} __packed;
/*--------------------------------------------------------------------
diff --git a/drivers/staging/wlan-ng/p80211types.h b/drivers/staging/wlan-ng/p80211types.h
index ac254542fde6..3dcdd022da61 100644
--- a/drivers/staging/wlan-ng/p80211types.h
+++ b/drivers/staging/wlan-ng/p80211types.h
@@ -204,7 +204,7 @@ struct p80211pstr {
struct p80211pstrd {
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
/* Maximum pascal string */
@@ -249,7 +249,7 @@ struct p80211itemd {
u32 did;
u16 status;
u16 len;
- u8 data[0];
+ u8 data[];
} __packed;
/* message data item for int, BOUNDEDINT, ENUMINT */
--
2.25.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] staging: Replace zero-length array with flexible-array member
@ 2020-02-20 13:29 ` Gustavo A. R. Silva
0 siblings, 0 replies; 6+ messages in thread
From: Gustavo A. R. Silva @ 2020-02-20 13:29 UTC (permalink / raw)
To: Greg Kroah-Hartman, Vaibhav Agarwal, Mark Greer, Johan Hovold,
Alex Elder, Michael Tretter, Pengutronix Kernel Team,
Mauro Carvalho Chehab, Larry Finger, Florian Schilhabel,
Adham Abozaeid, Ajay Singh
Cc: devel, Gustavo A. R. Silva, linux-wireless, linux-kernel,
greybus-dev, linux-media
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/staging/gdm724x/gdm_mux.h | 2 +-
drivers/staging/gdm724x/hci_packet.h | 6 ++--
drivers/staging/greybus/audio_apbridgea.h | 2 +-
drivers/staging/ks7010/ks_hostif.h | 4 +--
.../staging/media/allegro-dvt/allegro-core.c | 2 +-
drivers/staging/octeon-usb/octeon-hcd.c | 2 +-
drivers/staging/rtl8192e/rtllib.h | 30 +++++++++----------
.../staging/rtl8192u/ieee80211/ieee80211.h | 28 ++++++++---------
drivers/staging/rtl8712/ieee80211.h | 4 +--
drivers/staging/rtl8712/rtl871x_mp_ioctl.h | 4 +--
drivers/staging/wilc1000/cfg80211.c | 10 +++----
drivers/staging/wilc1000/spi.c | 2 +-
drivers/staging/wlan-ng/hfa384x.h | 4 +--
drivers/staging/wlan-ng/p80211types.h | 4 +--
14 files changed, 52 insertions(+), 52 deletions(-)
diff --git a/drivers/staging/gdm724x/gdm_mux.h b/drivers/staging/gdm724x/gdm_mux.h
index 51c22e3d8aeb..87b8d921fdc8 100644
--- a/drivers/staging/gdm724x/gdm_mux.h
+++ b/drivers/staging/gdm724x/gdm_mux.h
@@ -29,7 +29,7 @@ struct mux_pkt_header {
__le32 seq_num;
__le32 payload_size;
__le16 packet_type;
- unsigned char data[0];
+ unsigned char data[];
};
struct mux_tx {
diff --git a/drivers/staging/gdm724x/hci_packet.h b/drivers/staging/gdm724x/hci_packet.h
index 6dea3694afdd..faecdfbc664f 100644
--- a/drivers/staging/gdm724x/hci_packet.h
+++ b/drivers/staging/gdm724x/hci_packet.h
@@ -28,7 +28,7 @@
struct hci_packet {
__dev16 cmd_evt;
__dev16 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct tlv {
@@ -51,7 +51,7 @@ struct sdu {
__dev32 dft_eps_ID;
__dev32 bearer_ID;
__dev32 nic_type;
- u8 data[0];
+ u8 data[];
} __packed;
struct multi_sdu {
@@ -59,7 +59,7 @@ struct multi_sdu {
__dev16 len;
__dev16 num_packet;
__dev16 reserved;
- u8 data[0];
+ u8 data[];
} __packed;
struct hci_pdn_table_ind {
diff --git a/drivers/staging/greybus/audio_apbridgea.h b/drivers/staging/greybus/audio_apbridgea.h
index 3f1f4dd2c61a..efec0f815efd 100644
--- a/drivers/staging/greybus/audio_apbridgea.h
+++ b/drivers/staging/greybus/audio_apbridgea.h
@@ -65,7 +65,7 @@
struct audio_apbridgea_hdr {
__u8 type;
__le16 i2s_port;
- __u8 data[0];
+ __u8 data[];
} __packed;
struct audio_apbridgea_set_config_request {
diff --git a/drivers/staging/ks7010/ks_hostif.h b/drivers/staging/ks7010/ks_hostif.h
index ca7dc8f5166c..39138191a556 100644
--- a/drivers/staging/ks7010/ks_hostif.h
+++ b/drivers/staging/ks7010/ks_hostif.h
@@ -70,7 +70,7 @@ struct hostif_data_request {
#define TYPE_DATA 0x0000
#define TYPE_AUTH 0x0001
__le16 reserved;
- u8 data[0];
+ u8 data[];
} __packed;
#define TYPE_PMK1 0x0001
@@ -194,7 +194,7 @@ enum mib_data_type {
struct hostif_mib_value {
__le16 size;
__le16 type;
- u8 body[0];
+ u8 body[];
} __packed;
struct hostif_mib_get_confirm_t {
diff --git a/drivers/staging/media/allegro-dvt/allegro-core.c b/drivers/staging/media/allegro-dvt/allegro-core.c
index 3be41698df4c..0a09b3622e78 100644
--- a/drivers/staging/media/allegro-dvt/allegro-core.c
+++ b/drivers/staging/media/allegro-dvt/allegro-core.c
@@ -434,7 +434,7 @@ struct mcu_msg_push_buffers_internal_buffer {
struct mcu_msg_push_buffers_internal {
struct mcu_msg_header header;
u32 channel_id;
- struct mcu_msg_push_buffers_internal_buffer buffer[0];
+ struct mcu_msg_push_buffers_internal_buffer buffer[];
} __attribute__ ((__packed__));
struct mcu_msg_put_stream_buffer {
diff --git a/drivers/staging/octeon-usb/octeon-hcd.c b/drivers/staging/octeon-usb/octeon-hcd.c
index 582c9187559d..61471a19d4e6 100644
--- a/drivers/staging/octeon-usb/octeon-hcd.c
+++ b/drivers/staging/octeon-usb/octeon-hcd.c
@@ -406,7 +406,7 @@ struct octeon_hcd {
*/
struct octeon_temp_buffer {
void *orig_buffer;
- u8 data[0];
+ u8 data[];
};
static inline struct usb_hcd *octeon_to_hcd(struct octeon_hcd *p)
diff --git a/drivers/staging/rtl8192e/rtllib.h b/drivers/staging/rtl8192e/rtllib.h
index 328f410daa03..b84f00b8d18b 100644
--- a/drivers/staging/rtl8192e/rtllib.h
+++ b/drivers/staging/rtl8192e/rtllib.h
@@ -728,14 +728,14 @@ struct rtllib_pspoll_hdr {
struct rtllib_hdr {
__le16 frame_ctl;
__le16 duration_id;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_1addr {
__le16 frame_ctl;
__le16 duration_id;
u8 addr1[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_2addr {
@@ -743,7 +743,7 @@ struct rtllib_hdr_2addr {
__le16 duration_id;
u8 addr1[ETH_ALEN];
u8 addr2[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_3addr {
@@ -753,7 +753,7 @@ struct rtllib_hdr_3addr {
u8 addr2[ETH_ALEN];
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_4addr {
@@ -764,7 +764,7 @@ struct rtllib_hdr_4addr {
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
u8 addr4[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_3addrqos {
@@ -775,7 +775,7 @@ struct rtllib_hdr_3addrqos {
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
__le16 qos_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_hdr_4addrqos {
@@ -787,13 +787,13 @@ struct rtllib_hdr_4addrqos {
__le16 seq_ctl;
u8 addr4[ETH_ALEN];
__le16 qos_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtllib_info_element {
u8 id;
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct rtllib_authentication {
@@ -802,7 +802,7 @@ struct rtllib_authentication {
__le16 transaction;
__le16 status;
/*challenge*/
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
struct rtllib_disauth {
@@ -818,7 +818,7 @@ struct rtllib_disassoc {
struct rtllib_probe_request {
struct rtllib_hdr_3addr header;
/* SSID, supported rates */
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
struct rtllib_probe_response {
@@ -829,7 +829,7 @@ struct rtllib_probe_response {
/* SSID, supported rates, FH params, DS params,
* CF params, IBSS params, TIM (if beacon), RSN
*/
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
/* Alias beacon for probe_response */
@@ -840,7 +840,7 @@ struct rtllib_assoc_request_frame {
__le16 capability;
__le16 listen_interval;
/* SSID, supported rates, RSN */
- struct rtllib_info_element info_element[0];
+ struct rtllib_info_element info_element[];
} __packed;
struct rtllib_assoc_response_frame {
@@ -848,7 +848,7 @@ struct rtllib_assoc_response_frame {
__le16 capability;
__le16 status;
__le16 aid;
- struct rtllib_info_element info_element[0]; /* supported rates */
+ struct rtllib_info_element info_element[]; /* supported rates */
} __packed;
struct rtllib_txb {
@@ -859,7 +859,7 @@ struct rtllib_txb {
u16 reserved;
__le16 frag_size;
__le16 payload_size;
- struct sk_buff *fragments[0];
+ struct sk_buff *fragments[];
};
#define MAX_SUBFRAME_COUNT 64
@@ -1792,7 +1792,7 @@ struct rtllib_device {
/* This must be the last item so that it points to the data
* allocated beyond this structure by alloc_rtllib
*/
- u8 priv[0];
+ u8 priv[];
};
#define IEEE_A (1<<0)
diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211.h b/drivers/staging/rtl8192u/ieee80211/ieee80211.h
index 9576b647f6b1..39f4ddd86796 100644
--- a/drivers/staging/rtl8192u/ieee80211/ieee80211.h
+++ b/drivers/staging/rtl8192u/ieee80211/ieee80211.h
@@ -886,14 +886,14 @@ enum ieee80211_mfie {
struct rtl_80211_hdr {
__le16 frame_ctl;
__le16 duration_id;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_1addr {
__le16 frame_ctl;
__le16 duration_id;
u8 addr1[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_2addr {
@@ -901,7 +901,7 @@ struct rtl_80211_hdr_2addr {
__le16 duration_id;
u8 addr1[ETH_ALEN];
u8 addr2[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_3addr {
@@ -911,7 +911,7 @@ struct rtl_80211_hdr_3addr {
u8 addr2[ETH_ALEN];
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_4addr {
@@ -922,7 +922,7 @@ struct rtl_80211_hdr_4addr {
u8 addr3[ETH_ALEN];
__le16 seq_ctl;
u8 addr4[ETH_ALEN];
- u8 payload[0];
+ u8 payload[];
} __packed;
struct rtl_80211_hdr_3addrqos {
@@ -951,7 +951,7 @@ struct rtl_80211_hdr_4addrqos {
struct ieee80211_info_element {
u8 id;
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct ieee80211_authentication {
@@ -960,7 +960,7 @@ struct ieee80211_authentication {
__le16 transaction;
__le16 status;
/*challenge*/
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_disassoc {
@@ -971,7 +971,7 @@ struct ieee80211_disassoc {
struct ieee80211_probe_request {
struct rtl_80211_hdr_3addr header;
/* SSID, supported rates */
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_probe_response {
@@ -982,7 +982,7 @@ struct ieee80211_probe_response {
/* SSID, supported rates, FH params, DS params,
* CF params, IBSS params, TIM (if beacon), RSN
*/
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
/* Alias beacon for probe_response */
@@ -993,7 +993,7 @@ struct ieee80211_assoc_request_frame {
__le16 capability;
__le16 listen_interval;
/* SSID, supported rates, RSN */
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_reassoc_request_frame {
@@ -1002,7 +1002,7 @@ struct ieee80211_reassoc_request_frame {
__le16 listen_interval;
u8 current_ap[ETH_ALEN];
/* SSID, supported rates, RSN */
- struct ieee80211_info_element info_element[0];
+ struct ieee80211_info_element info_element[];
} __packed;
struct ieee80211_assoc_response_frame {
@@ -1010,7 +1010,7 @@ struct ieee80211_assoc_response_frame {
__le16 capability;
__le16 status;
__le16 aid;
- struct ieee80211_info_element info_element[0]; /* supported rates */
+ struct ieee80211_info_element info_element[]; /* supported rates */
} __packed;
struct ieee80211_txb {
@@ -1021,7 +1021,7 @@ struct ieee80211_txb {
u16 reserved;
__le16 frag_size;
__le16 payload_size;
- struct sk_buff *fragments[0];
+ struct sk_buff *fragments[];
};
#define MAX_TX_AGG_COUNT 16
@@ -2007,7 +2007,7 @@ struct ieee80211_device {
/* This must be the last item so that it points to the data
* allocated beyond this structure by alloc_ieee80211
*/
- u8 priv[0];
+ u8 priv[];
};
#define IEEE_A (1<<0)
diff --git a/drivers/staging/rtl8712/ieee80211.h b/drivers/staging/rtl8712/ieee80211.h
index 8098f6905554..dabaa8fd34fb 100644
--- a/drivers/staging/rtl8712/ieee80211.h
+++ b/drivers/staging/rtl8712/ieee80211.h
@@ -535,7 +535,7 @@ struct ieee80211_info_element_hdr {
struct ieee80211_info_element {
u8 id;
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
/*
@@ -597,7 +597,7 @@ struct ieee80211_txb {
u16 reserved;
u16 frag_size;
u16 payload_size;
- struct sk_buff *fragments[0];
+ struct sk_buff *fragments[];
};
/* SWEEP TABLE ENTRIES NUMBER*/
diff --git a/drivers/staging/rtl8712/rtl871x_mp_ioctl.h b/drivers/staging/rtl8712/rtl871x_mp_ioctl.h
index 64e2ae436625..59fa6664d868 100644
--- a/drivers/staging/rtl8712/rtl871x_mp_ioctl.h
+++ b/drivers/staging/rtl8712/rtl871x_mp_ioctl.h
@@ -48,7 +48,7 @@ struct eeprom_rw_param {
struct EFUSE_ACCESS_STRUCT {
u16 start_addr;
u16 cnts;
- u8 data[0];
+ u8 data[];
};
struct burst_rw_reg {
@@ -324,7 +324,7 @@ struct mp_ioctl_handler {
struct mp_ioctl_param {
unsigned int subcode;
unsigned int len;
- unsigned char data[0];
+ unsigned char data[];
};
#define GEN_MP_IOCTL_SUBCODE(code) _MP_IOCTL_ ## code ## _CMD_
diff --git a/drivers/staging/wilc1000/cfg80211.c b/drivers/staging/wilc1000/cfg80211.c
index 995b1f306807..5d8faa01337d 100644
--- a/drivers/staging/wilc1000/cfg80211.c
+++ b/drivers/staging/wilc1000/cfg80211.c
@@ -62,7 +62,7 @@ struct wilc_p2p_pub_act_frame {
u8 oui_type;
u8 oui_subtype;
u8 dialog_token;
- u8 elem[0];
+ u8 elem[];
} __packed;
struct wilc_vendor_specific_ie {
@@ -70,13 +70,13 @@ struct wilc_vendor_specific_ie {
u8 tag_len;
u8 oui[3];
u8 oui_type;
- u8 attr[0];
+ u8 attr[];
} __packed;
struct wilc_attr_entry {
u8 attr_type;
__le16 attr_len;
- u8 val[0];
+ u8 val[];
} __packed;
struct wilc_attr_oper_ch {
@@ -91,13 +91,13 @@ struct wilc_attr_ch_list {
u8 attr_type;
__le16 attr_len;
u8 country_code[IEEE80211_COUNTRY_STRING_LEN];
- u8 elem[0];
+ u8 elem[];
} __packed;
struct wilc_ch_list_elem {
u8 op_class;
u8 no_of_channels;
- u8 ch_list[0];
+ u8 ch_list[];
} __packed;
static void cfg_scan_result(enum scan_event scan_event,
diff --git a/drivers/staging/wilc1000/spi.c b/drivers/staging/wilc1000/spi.c
index 44f7d48851b5..11653ac118cd 100644
--- a/drivers/staging/wilc1000/spi.c
+++ b/drivers/staging/wilc1000/spi.c
@@ -139,7 +139,7 @@ struct wilc_spi_read_rsp_data {
u8 status;
u8 resp_header;
u8 resp_data[4];
- u8 crc[0];
+ u8 crc[];
} __packed;
struct wilc_spi_rsp_data {
diff --git a/drivers/staging/wlan-ng/hfa384x.h b/drivers/staging/wlan-ng/hfa384x.h
index bdd7f414fdbb..88e894dd3568 100644
--- a/drivers/staging/wlan-ng/hfa384x.h
+++ b/drivers/staging/wlan-ng/hfa384x.h
@@ -355,7 +355,7 @@
/* Commonly used basic types */
struct hfa384x_bytestr {
__le16 len;
- u8 data[0];
+ u8 data[];
} __packed;
struct hfa384x_bytestr32 {
@@ -421,7 +421,7 @@ struct hfa384x_authenticate_station_data {
/*-- Configuration Record: WPAData (data portion only) --*/
struct hfa384x_wpa_data {
__le16 datalen;
- u8 data[0]; /* max 80 */
+ u8 data[]; /* max 80 */
} __packed;
/*--------------------------------------------------------------------
diff --git a/drivers/staging/wlan-ng/p80211types.h b/drivers/staging/wlan-ng/p80211types.h
index ac254542fde6..3dcdd022da61 100644
--- a/drivers/staging/wlan-ng/p80211types.h
+++ b/drivers/staging/wlan-ng/p80211types.h
@@ -204,7 +204,7 @@ struct p80211pstr {
struct p80211pstrd {
u8 len;
- u8 data[0];
+ u8 data[];
} __packed;
/* Maximum pascal string */
@@ -249,7 +249,7 @@ struct p80211itemd {
u32 did;
u16 status;
u16 len;
- u8 data[0];
+ u8 data[];
} __packed;
/* message data item for int, BOUNDEDINT, ENUMINT */
--
2.25.0
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] staging: Replace zero-length array with flexible-array member
2020-02-20 13:29 ` Gustavo A. R. Silva
@ 2020-02-20 19:04 ` Adham.Abozaeid
-1 siblings, 0 replies; 6+ messages in thread
From: Adham.Abozaeid @ 2020-02-20 19:04 UTC (permalink / raw)
To: gustavo, gregkh, vaibhav.sr, mgreer, johan, elder, m.tretter,
kernel, mchehab, Larry.Finger, florian.c.schilhabel, Ajay.Kathat
Cc: devel, linux-kernel, greybus-dev, linux-media, linux-wireless
Hi Gustavo
On 2/20/20 6:29 AM, Gustavo A. R. Silva wrote:
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2],
> introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> inadvertently introduced[3] to the codebase from now on.
>
> Also, notice that, dynamic memory allocations won't be affected by
> this change:
>
> "Flexible array members have incomplete type, and so the sizeof operator
> may not be applied. As a quirk of the original implementation of
> zero-length arrays, sizeof evaluates to zero."[1]
>
> This issue was found with the help of Coccinelle.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>
> static void cfg_scan_result(enum scan_event scan_event,
> diff --git a/drivers/staging/wilc1000/spi.c b/drivers/staging/wilc1000/spi.c
> index 44f7d48851b5..11653ac118cd 100644
> --- a/drivers/staging/wilc1000/spi.c
> +++ b/drivers/staging/wilc1000/spi.c
> @@ -139,7 +139,7 @@ struct wilc_spi_read_rsp_data {
> u8 status;
> u8 resp_header;
> u8 resp_data[4];
> - u8 crc[0];
> + u8 crc[];
> } __packed;
more zero-length arrays in wilc1000, spi.c, struct wilc_spi_cmd, and in fw.h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] staging: Replace zero-length array with flexible-array member
@ 2020-02-20 19:04 ` Adham.Abozaeid
0 siblings, 0 replies; 6+ messages in thread
From: Adham.Abozaeid @ 2020-02-20 19:04 UTC (permalink / raw)
To: gustavo, gregkh, vaibhav.sr, mgreer, johan, elder, m.tretter,
kernel, mchehab, Larry.Finger, florian.c.schilhabel, Ajay.Kathat
Cc: devel, greybus-dev, linux-wireless, linux-kernel, linux-media
Hi Gustavo
On 2/20/20 6:29 AM, Gustavo A. R. Silva wrote:
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2],
> introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> inadvertently introduced[3] to the codebase from now on.
>
> Also, notice that, dynamic memory allocations won't be affected by
> this change:
>
> "Flexible array members have incomplete type, and so the sizeof operator
> may not be applied. As a quirk of the original implementation of
> zero-length arrays, sizeof evaluates to zero."[1]
>
> This issue was found with the help of Coccinelle.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>
> static void cfg_scan_result(enum scan_event scan_event,
> diff --git a/drivers/staging/wilc1000/spi.c b/drivers/staging/wilc1000/spi.c
> index 44f7d48851b5..11653ac118cd 100644
> --- a/drivers/staging/wilc1000/spi.c
> +++ b/drivers/staging/wilc1000/spi.c
> @@ -139,7 +139,7 @@ struct wilc_spi_read_rsp_data {
> u8 status;
> u8 resp_header;
> u8 resp_data[4];
> - u8 crc[0];
> + u8 crc[];
> } __packed;
more zero-length arrays in wilc1000, spi.c, struct wilc_spi_cmd, and in fw.h
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] staging: Replace zero-length array with flexible-array member
2020-02-20 19:04 ` Adham.Abozaeid
@ 2020-02-20 19:14 ` Gustavo A. R. Silva
-1 siblings, 0 replies; 6+ messages in thread
From: Gustavo A. R. Silva @ 2020-02-20 19:14 UTC (permalink / raw)
To: Adham.Abozaeid, gregkh, vaibhav.sr, mgreer, johan, elder,
m.tretter, kernel, mchehab, Larry.Finger, florian.c.schilhabel,
Ajay.Kathat
Cc: devel, linux-kernel, greybus-dev, linux-media, linux-wireless
Hi,
On 2/20/20 13:04, Adham.Abozaeid@microchip.com wrote:
> Hi Gustavo
>
> On 2/20/20 6:29 AM, Gustavo A. R. Silva wrote:
>> The current codebase makes use of the zero-length array language
>> extension to the C90 standard, but the preferred mechanism to declare
>> variable-length types such as these ones is a flexible array member[1][2],
>> introduced in C99:
>>
>> struct foo {
>> int stuff;
>> struct boo array[];
>> };
>>
>> By making use of the mechanism above, we will get a compiler warning
>> in case the flexible array does not occur last in the structure, which
>> will help us prevent some kind of undefined behavior bugs from being
>> inadvertently introduced[3] to the codebase from now on.
>>
>> Also, notice that, dynamic memory allocations won't be affected by
>> this change:
>>
>> "Flexible array members have incomplete type, and so the sizeof operator
>> may not be applied. As a quirk of the original implementation of
>> zero-length arrays, sizeof evaluates to zero."[1]
>>
>> This issue was found with the help of Coccinelle.
>>
>> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
>> [2] https://github.com/KSPP/linux/issues/21
>> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>
>> static void cfg_scan_result(enum scan_event scan_event,
>> diff --git a/drivers/staging/wilc1000/spi.c b/drivers/staging/wilc1000/spi.c
>> index 44f7d48851b5..11653ac118cd 100644
>> --- a/drivers/staging/wilc1000/spi.c
>> +++ b/drivers/staging/wilc1000/spi.c
>> @@ -139,7 +139,7 @@ struct wilc_spi_read_rsp_data {
>> u8 status;
>> u8 resp_header;
>> u8 resp_data[4];
>> - u8 crc[0];
>> + u8 crc[];
>> } __packed;
> more zero-length arrays in wilc1000, spi.c, struct wilc_spi_cmd, and in fw.h
>
Oh wow, I hadn't thought about cases like this:
struct wilc_spi_cmd {
u8 cmd_type;
union {
struct {
u8 addr[3];
u8 crc[0];
} __packed simple_cmd;
struct {
u8 addr[3];
u8 size[2];
u8 crc[0];
} __packed dma_cmd;
struct {
u8 addr[3];
u8 size[3];
u8 crc[0];
} __packed dma_cmd_ext;
struct {
u8 addr[2];
__be32 data;
u8 crc[0];
} __packed internal_w_cmd;
struct {
u8 addr[3];
__be32 data;
u8 crc[0];
} __packed w_cmd;
} u;
} __packed;
Thanks for the feedback.
--
Gustavo
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] staging: Replace zero-length array with flexible-array member
@ 2020-02-20 19:14 ` Gustavo A. R. Silva
0 siblings, 0 replies; 6+ messages in thread
From: Gustavo A. R. Silva @ 2020-02-20 19:14 UTC (permalink / raw)
To: Adham.Abozaeid, gregkh, vaibhav.sr, mgreer, johan, elder,
m.tretter, kernel, mchehab, Larry.Finger, florian.c.schilhabel,
Ajay.Kathat
Cc: devel, greybus-dev, linux-wireless, linux-kernel, linux-media
Hi,
On 2/20/20 13:04, Adham.Abozaeid@microchip.com wrote:
> Hi Gustavo
>
> On 2/20/20 6:29 AM, Gustavo A. R. Silva wrote:
>> The current codebase makes use of the zero-length array language
>> extension to the C90 standard, but the preferred mechanism to declare
>> variable-length types such as these ones is a flexible array member[1][2],
>> introduced in C99:
>>
>> struct foo {
>> int stuff;
>> struct boo array[];
>> };
>>
>> By making use of the mechanism above, we will get a compiler warning
>> in case the flexible array does not occur last in the structure, which
>> will help us prevent some kind of undefined behavior bugs from being
>> inadvertently introduced[3] to the codebase from now on.
>>
>> Also, notice that, dynamic memory allocations won't be affected by
>> this change:
>>
>> "Flexible array members have incomplete type, and so the sizeof operator
>> may not be applied. As a quirk of the original implementation of
>> zero-length arrays, sizeof evaluates to zero."[1]
>>
>> This issue was found with the help of Coccinelle.
>>
>> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
>> [2] https://github.com/KSPP/linux/issues/21
>> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>
>> static void cfg_scan_result(enum scan_event scan_event,
>> diff --git a/drivers/staging/wilc1000/spi.c b/drivers/staging/wilc1000/spi.c
>> index 44f7d48851b5..11653ac118cd 100644
>> --- a/drivers/staging/wilc1000/spi.c
>> +++ b/drivers/staging/wilc1000/spi.c
>> @@ -139,7 +139,7 @@ struct wilc_spi_read_rsp_data {
>> u8 status;
>> u8 resp_header;
>> u8 resp_data[4];
>> - u8 crc[0];
>> + u8 crc[];
>> } __packed;
> more zero-length arrays in wilc1000, spi.c, struct wilc_spi_cmd, and in fw.h
>
Oh wow, I hadn't thought about cases like this:
struct wilc_spi_cmd {
u8 cmd_type;
union {
struct {
u8 addr[3];
u8 crc[0];
} __packed simple_cmd;
struct {
u8 addr[3];
u8 size[2];
u8 crc[0];
} __packed dma_cmd;
struct {
u8 addr[3];
u8 size[3];
u8 crc[0];
} __packed dma_cmd_ext;
struct {
u8 addr[2];
__be32 data;
u8 crc[0];
} __packed internal_w_cmd;
struct {
u8 addr[3];
__be32 data;
u8 crc[0];
} __packed w_cmd;
} u;
} __packed;
Thanks for the feedback.
--
Gustavo
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^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-02-20 19:57 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-20 13:29 [PATCH] staging: Replace zero-length array with flexible-array member Gustavo A. R. Silva
2020-02-20 13:29 ` Gustavo A. R. Silva
2020-02-20 19:04 ` Adham.Abozaeid
2020-02-20 19:04 ` Adham.Abozaeid
2020-02-20 19:14 ` Gustavo A. R. Silva
2020-02-20 19:14 ` Gustavo A. R. Silva
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