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@xxxxxxxxxxxxxx>
---
drivers/usb/atm/usbatm.h | 2 +-
drivers/usb/dwc2/hcd.h | 2 +-
drivers/usb/host/ehci-tegra.c | 2 +-
drivers/usb/host/ehci.h | 4 ++--
drivers/usb/host/fotg210.h | 2 +-
drivers/usb/host/ohci.h | 4 ++--
drivers/usb/host/xhci-mtk.h | 2 +-
drivers/usb/host/xhci.h | 4 ++--
drivers/usb/serial/io_usbvend.h | 4 ++--
drivers/usb/serial/ti_usb_3410_5052.c | 4 ++--
include/linux/usb.h | 4 ++--
include/linux/usb/audio-v2.h | 2 +-
include/linux/usb/audio-v3.h | 2 +-
include/linux/usb/gadget.h | 2 +-
include/linux/usb/hcd.h | 2 +-
include/linux/usbdevice_fs.h | 2 +-
16 files changed, 22 insertions(+), 22 deletions(-)
diff --git a/drivers/usb/atm/usbatm.h b/drivers/usb/atm/usbatm.h
index d3bdc4cc47aa..8725755bd53d 100644
--- a/drivers/usb/atm/usbatm.h
+++ b/drivers/usb/atm/usbatm.h
@@ -164,7 +164,7 @@ struct usbatm_data {
unsigned char *cell_buf; /* holds partial rx cell */
unsigned int buf_usage;
- struct urb *urbs[0];
+ struct urb *urbs[];
};
static inline void *to_usbatm_driver_data(struct usb_interface *intf)
diff --git a/drivers/usb/dwc2/hcd.h b/drivers/usb/dwc2/hcd.h
index 8ca6d12a6f57..1224fa9df604 100644
--- a/drivers/usb/dwc2/hcd.h
+++ b/drivers/usb/dwc2/hcd.h
@@ -199,7 +199,7 @@ struct dwc2_hcd_urb {
u32 flags;
u16 interval;
struct dwc2_hcd_pipe_info pipe_info;
- struct dwc2_hcd_iso_packet_desc iso_descs[0];
+ struct dwc2_hcd_iso_packet_desc iso_descs[];
};
/* Phases for control transfers */
diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index d6433f206c17..10d51daa6a1b 100644
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -282,7 +282,7 @@ static int tegra_ehci_hub_control(
struct dma_aligned_buffer {
void *kmalloc_ptr;
void *old_xfer_buffer;
- u8 data[0];
+ u8 data[];
};
static void free_dma_aligned_buffer(struct urb *urb)
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index ac5e967907d1..229b3de319e6 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -255,7 +255,7 @@ struct ehci_hcd { /* one per controller */
struct list_head tt_list;
/* platform-specific data -- must come last */
- unsigned long priv[0] __aligned(sizeof(s64));
+ unsigned long priv[] __aligned(sizeof(s64));
};
/* convert between an HCD pointer and the corresponding EHCI_HCD */
@@ -460,7 +460,7 @@ struct ehci_iso_sched {
struct list_head td_list;
unsigned span;
unsigned first_packet;
- struct ehci_iso_packet packet[0];
+ struct ehci_iso_packet packet[];
};
/*
diff --git a/drivers/usb/host/fotg210.h b/drivers/usb/host/fotg210.h
index 1b4db95e5c43..6cee40ec65b4 100644
--- a/drivers/usb/host/fotg210.h
+++ b/drivers/usb/host/fotg210.h
@@ -490,7 +490,7 @@ struct fotg210_iso_packet {
struct fotg210_iso_sched {
struct list_head td_list;
unsigned span;
- struct fotg210_iso_packet packet[0];
+ struct fotg210_iso_packet packet[];
};
/*
diff --git a/drivers/usb/host/ohci.h b/drivers/usb/host/ohci.h
index b015b00774b2..27c26ca10bfd 100644
--- a/drivers/usb/host/ohci.h
+++ b/drivers/usb/host/ohci.h
@@ -337,7 +337,7 @@ typedef struct urb_priv {
u16 length; // # tds in this request
u16 td_cnt; // tds already serviced
struct list_head pending;
- struct td *td [0]; // all TDs in this request
+ struct td *td[]; // all TDs in this request
} urb_priv_t;
@@ -435,7 +435,7 @@ struct ohci_hcd {
struct dentry *debug_dir;
/* platform-specific data -- must come last */
- unsigned long priv[0] __aligned(sizeof(s64));
+ unsigned long priv[] __aligned(sizeof(s64));
};
diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
index 5ac458b7d2e0..acd56517215a 100644
--- a/drivers/usb/host/xhci-mtk.h
+++ b/drivers/usb/host/xhci-mtk.h
@@ -95,7 +95,7 @@ struct mu3h_sch_ep_info {
u32 pkts;
u32 cs_count;
u32 burst_mode;
- u32 bw_budget_table[0];
+ u32 bw_budget_table[];
};
#define MU3C_U3_PORT_MAX 4
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 3ecee10fdcdc..685180e1b98a 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1642,7 +1642,7 @@ struct xhci_scratchpad {
struct urb_priv {
int num_tds;
int num_tds_done;
- struct xhci_td td[0];
+ struct xhci_td td[];
};
/*
@@ -1901,7 +1901,7 @@ struct xhci_hcd {
void *dbc;
/* platform-specific data -- must come last */
- unsigned long priv[0] __aligned(sizeof(s64));
+ unsigned long priv[] __aligned(sizeof(s64));
};
/* Platform specific overrides to generic XHCI hc_driver ops */
diff --git a/drivers/usb/serial/io_usbvend.h b/drivers/usb/serial/io_usbvend.h
index c38e87ac5ea9..0d1a5bb4636e 100644
--- a/drivers/usb/serial/io_usbvend.h
+++ b/drivers/usb/serial/io_usbvend.h
@@ -593,7 +593,7 @@ struct ti_i2c_desc {
__u8 Type; // Type of descriptor
__le16 Size; // Size of data only not including header
__u8 CheckSum; // Checksum (8 bit sum of data only)
- __u8 Data[0]; // Data starts here
+ __u8 Data[]; // Data starts here
} __attribute__((packed));
// for 5152 devices only (type 2 record)
@@ -601,7 +601,7 @@ struct ti_i2c_desc {
struct ti_i2c_firmware_rec {
__u8 Ver_Major; // Firmware Major version number
__u8 Ver_Minor; // Firmware Minor version number
- __u8 Data[0]; // Download starts here
+ __u8 Data[]; // Download starts here
} __attribute__((packed));
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index ef23acc9b9ce..73075b9351c5 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -219,7 +219,7 @@ struct ti_write_data_bytes {
u8 bDataCounter;
__be16 wBaseAddrHi;
__be16 wBaseAddrLo;
- u8 bData[0];
+ u8 bData[];
} __packed;
struct ti_read_data_request {
@@ -234,7 +234,7 @@ struct ti_read_data_bytes {
__u8 bCmdCode;
__u8 bModuleId;
__u8 bErrorCode;
- __u8 bData[0];
+ __u8 bData[];
} __packed;
/* Interrupt struct */
diff --git a/include/linux/usb.h b/include/linux/usb.h
index ca1a5f1e1c5e..9f3c721c70dc 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -325,7 +325,7 @@ struct usb_interface_cache {
/* variable-length array of alternate settings for this interface,
* stored in no particular order */
- struct usb_host_interface altsetting[0];
+ struct usb_host_interface altsetting[];
};
#define ref_to_usb_interface_cache(r) \
container_of(r, struct usb_interface_cache, ref)
@@ -1589,7 +1589,7 @@ struct urb {
int error_count; /* (return) number of ISO errors */
void *context; /* (in) context for completion */
usb_complete_t complete; /* (in) completion routine */
- struct usb_iso_packet_descriptor iso_frame_desc[0];
+ struct usb_iso_packet_descriptor iso_frame_desc[];
/* (in) ISO ONLY */
};
diff --git a/include/linux/usb/audio-v2.h b/include/linux/usb/audio-v2.h
index cb9900b34b67..ead8c9a47c6a 100644
--- a/include/linux/usb/audio-v2.h
+++ b/include/linux/usb/audio-v2.h
@@ -153,7 +153,7 @@ struct uac2_feature_unit_descriptor {
__u8 bSourceID;
/* bmaControls is actually u32,
* but u8 is needed for the hybrid parser */
- __u8 bmaControls[0]; /* variable length */
+ __u8 bmaControls[]; /* variable length */
} __attribute__((packed));
/* 4.7.2.10 Effect Unit Descriptor */
diff --git a/include/linux/usb/audio-v3.h b/include/linux/usb/audio-v3.h
index 6b708434b7f9..c69a6f2e6837 100644
--- a/include/linux/usb/audio-v3.h
+++ b/include/linux/usb/audio-v3.h
@@ -109,7 +109,7 @@ struct uac3_feature_unit_descriptor {
__u8 bSourceID;
/* bmaControls is actually u32,
* but u8 is needed for the hybrid parser */
- __u8 bmaControls[0]; /* variable length */
+ __u8 bmaControls[]; /* variable length */
/* wFeatureDescrStr omitted */
} __attribute__((packed));
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 124462d65eac..9411c08a5c7e 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -767,7 +767,7 @@ struct usb_gadget_strings {
struct usb_gadget_string_container {
struct list_head list;
- u8 *stash[0];
+ u8 *stash[];
};
/* put descriptor for string with that id into buf (buflen >= 256) */
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 712b2a603645..e12105ed3834 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -228,7 +228,7 @@ struct usb_hcd {
/* The HC driver's private data is stored at the end of
* this structure.
*/
- unsigned long hcd_priv[0]
+ unsigned long hcd_priv[]
__attribute__ ((aligned(sizeof(s64))));
};
diff --git a/include/linux/usbdevice_fs.h b/include/linux/usbdevice_fs.h
index 79aab0065ec8..14ea197ce37f 100644
--- a/include/linux/usbdevice_fs.h
+++ b/include/linux/usbdevice_fs.h
@@ -69,7 +69,7 @@ struct usbdevfs_urb32 {
compat_int_t error_count;
compat_uint_t signr;
compat_caddr_t usercontext; /* unused */
- struct usbdevfs_iso_packet_desc iso_frame_desc[0];
+ struct usbdevfs_iso_packet_desc iso_frame_desc[];
};
struct usbdevfs_ioctl32 {
--
2.25.0
