* [PATCH][next] Bluetooth: Avoid a couple dozen -Wflex-array-member-not-at-end warnings
@ 2025-08-31 17:13 Gustavo A. R. Silva
2025-08-31 18:02 ` Gustavo A. R. Silva
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2025-08-31 17:13 UTC (permalink / raw)
To: Marcel Holtmann, Johan Hedberg, Luiz Augusto von Dentz
Cc: linux-bluetooth, linux-kernel, Gustavo A. R. Silva, linux-hardening
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
Use the new TRAILING_OVERLAP() helper to fix 31 instances of the
following type of warnings:
30 net/bluetooth/mgmt_config.c:16:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
1 net/bluetooth/mgmt_config.c:22:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
This helper creates a union between a flexible-array member (FAM)
and a set of members that would otherwise follow it. This overlays
the trailing members onto the FAM while preserving the original
memory layout.
Also, as the structs turn into unions, both members `entry` and
`value` cannot be statically initialized at once. Create another
macro to initialize everything after the declaration of `rp`.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
net/bluetooth/mgmt_config.c | 97 +++++++++++++++++++------------------
1 file changed, 51 insertions(+), 46 deletions(-)
diff --git a/net/bluetooth/mgmt_config.c b/net/bluetooth/mgmt_config.c
index 6ef701c27da4..829c9cfcea7d 100644
--- a/net/bluetooth/mgmt_config.c
+++ b/net/bluetooth/mgmt_config.c
@@ -12,35 +12,71 @@
#include "mgmt_config.h"
#define HDEV_PARAM_U16(_param_name_) \
- struct {\
- struct mgmt_tlv entry; \
+ TRAILING_OVERLAP(struct mgmt_tlv, entry, value, \
__le16 value; \
- } __packed _param_name_
+ ) __packed _param_name_
#define HDEV_PARAM_U8(_param_name_) \
- struct {\
- struct mgmt_tlv entry; \
+ TRAILING_OVERLAP(struct mgmt_tlv, entry, value, \
__u8 value; \
- } __packed _param_name_
+ ) __packed _param_name_
#define TLV_SET_U16(_param_code_, _param_name_) \
{ \
- { cpu_to_le16(_param_code_), sizeof(__u16) }, \
- cpu_to_le16(hdev->_param_name_) \
+ rp._param_name_.entry.type = cpu_to_le16(_param_code_); \
+ rp._param_name_.entry.length = sizeof(__u16); \
+ rp._param_name_.value = cpu_to_le16(hdev->_param_name_); \
}
#define TLV_SET_U8(_param_code_, _param_name_) \
{ \
- { cpu_to_le16(_param_code_), sizeof(__u8) }, \
- hdev->_param_name_ \
+ rp._param_name_.entry.type = cpu_to_le16(_param_code_); \
+ rp._param_name_.entry.length = sizeof(__u8); \
+ rp._param_name_.value = hdev->_param_name_; \
}
#define TLV_SET_U16_JIFFIES_TO_MSECS(_param_code_, _param_name_) \
{ \
- { cpu_to_le16(_param_code_), sizeof(__u16) }, \
- cpu_to_le16(jiffies_to_msecs(hdev->_param_name_)) \
+ rp._param_name_.entry.type = cpu_to_le16(_param_code_); \
+ rp._param_name_.entry.length = sizeof(__u16); \
+ rp._param_name_.value = cpu_to_le16(jiffies_to_msecs(hdev->_param_name_)); \
}
+#define TLV_SET_ALL() \
+{ \
+ TLV_SET_U16(0x0000, def_page_scan_type); \
+ TLV_SET_U16(0x0001, def_page_scan_int); \
+ TLV_SET_U16(0x0002, def_page_scan_window); \
+ TLV_SET_U16(0x0003, def_inq_scan_type); \
+ TLV_SET_U16(0x0004, def_inq_scan_int); \
+ TLV_SET_U16(0x0005, def_inq_scan_window); \
+ TLV_SET_U16(0x0006, def_br_lsto); \
+ TLV_SET_U16(0x0007, def_page_timeout); \
+ TLV_SET_U16(0x0008, sniff_min_interval); \
+ TLV_SET_U16(0x0009, sniff_max_interval); \
+ TLV_SET_U16(0x000a, le_adv_min_interval); \
+ TLV_SET_U16(0x000b, le_adv_max_interval); \
+ TLV_SET_U16(0x000c, def_multi_adv_rotation_duration); \
+ TLV_SET_U16(0x000d, le_scan_interval); \
+ TLV_SET_U16(0x000e, le_scan_window); \
+ TLV_SET_U16(0x000f, le_scan_int_suspend); \
+ TLV_SET_U16(0x0010, le_scan_window_suspend); \
+ TLV_SET_U16(0x0011, le_scan_int_discovery); \
+ TLV_SET_U16(0x0012, le_scan_window_discovery); \
+ TLV_SET_U16(0x0013, le_scan_int_adv_monitor); \
+ TLV_SET_U16(0x0014, le_scan_window_adv_monitor); \
+ TLV_SET_U16(0x0015, le_scan_int_connect); \
+ TLV_SET_U16(0x0016, le_scan_window_connect); \
+ TLV_SET_U16(0x0017, le_conn_min_interval); \
+ TLV_SET_U16(0x0018, le_conn_max_interval); \
+ TLV_SET_U16(0x0019, le_conn_latency); \
+ TLV_SET_U16(0x001a, le_supv_timeout); \
+ TLV_SET_U16_JIFFIES_TO_MSECS(0x001b, def_le_autoconnect_timeout); \
+ TLV_SET_U16(0x001d, advmon_allowlist_duration); \
+ TLV_SET_U16(0x001e, advmon_no_filter_duration); \
+ TLV_SET_U8(0x001f, enable_advmon_interleave_scan); \
+}
+
int read_def_system_config(struct sock *sk, struct hci_dev *hdev, void *data,
u16 data_len)
{
@@ -78,40 +114,9 @@ int read_def_system_config(struct sock *sk, struct hci_dev *hdev, void *data,
HDEV_PARAM_U16(advmon_allowlist_duration);
HDEV_PARAM_U16(advmon_no_filter_duration);
HDEV_PARAM_U8(enable_advmon_interleave_scan);
- } __packed rp = {
- TLV_SET_U16(0x0000, def_page_scan_type),
- TLV_SET_U16(0x0001, def_page_scan_int),
- TLV_SET_U16(0x0002, def_page_scan_window),
- TLV_SET_U16(0x0003, def_inq_scan_type),
- TLV_SET_U16(0x0004, def_inq_scan_int),
- TLV_SET_U16(0x0005, def_inq_scan_window),
- TLV_SET_U16(0x0006, def_br_lsto),
- TLV_SET_U16(0x0007, def_page_timeout),
- TLV_SET_U16(0x0008, sniff_min_interval),
- TLV_SET_U16(0x0009, sniff_max_interval),
- TLV_SET_U16(0x000a, le_adv_min_interval),
- TLV_SET_U16(0x000b, le_adv_max_interval),
- TLV_SET_U16(0x000c, def_multi_adv_rotation_duration),
- TLV_SET_U16(0x000d, le_scan_interval),
- TLV_SET_U16(0x000e, le_scan_window),
- TLV_SET_U16(0x000f, le_scan_int_suspend),
- TLV_SET_U16(0x0010, le_scan_window_suspend),
- TLV_SET_U16(0x0011, le_scan_int_discovery),
- TLV_SET_U16(0x0012, le_scan_window_discovery),
- TLV_SET_U16(0x0013, le_scan_int_adv_monitor),
- TLV_SET_U16(0x0014, le_scan_window_adv_monitor),
- TLV_SET_U16(0x0015, le_scan_int_connect),
- TLV_SET_U16(0x0016, le_scan_window_connect),
- TLV_SET_U16(0x0017, le_conn_min_interval),
- TLV_SET_U16(0x0018, le_conn_max_interval),
- TLV_SET_U16(0x0019, le_conn_latency),
- TLV_SET_U16(0x001a, le_supv_timeout),
- TLV_SET_U16_JIFFIES_TO_MSECS(0x001b,
- def_le_autoconnect_timeout),
- TLV_SET_U16(0x001d, advmon_allowlist_duration),
- TLV_SET_U16(0x001e, advmon_no_filter_duration),
- TLV_SET_U8(0x001f, enable_advmon_interleave_scan),
- };
+ } __packed rp;
+
+ TLV_SET_ALL();
bt_dev_dbg(hdev, "sock %p", sk);
--
2.43.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH][next] Bluetooth: Avoid a couple dozen -Wflex-array-member-not-at-end warnings
2025-08-31 17:13 [PATCH][next] Bluetooth: Avoid a couple dozen -Wflex-array-member-not-at-end warnings Gustavo A. R. Silva
@ 2025-08-31 18:02 ` Gustavo A. R. Silva
0 siblings, 0 replies; 2+ messages in thread
From: Gustavo A. R. Silva @ 2025-08-31 18:02 UTC (permalink / raw)
To: Gustavo A. R. Silva, Marcel Holtmann, Johan Hedberg,
Luiz Augusto von Dentz
Cc: linux-bluetooth, linux-kernel, linux-hardening
Hi all,
Please, drop this. I just remembered about this bugfix for GCC:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120354
which will actually catch the same -Wfamnae issues inside
struct mgmt_rp_read_def_system_config:
struct mgmt_rp_read_def_system_config {
union {
struct mgmt_tlv entry; /* 0 3 */
struct {
unsigned char __offset_to_value[3]; /* 0 3 */
/* XXX 1 byte hole, try to pack */
__le16 value; /* 4 2 */
}; /* 0 6 */
} def_page_scan_type; /* 0 6 */
union {
struct mgmt_tlv entry; /* 6 3 */
struct {
unsigned char __offset_to_value[3]; /* 6 3 */
/* XXX 1 byte hole, try to pack */
__le16 value; /* 10 2 */
}; /* 6 6 */
} def_page_scan_int; /* 6 6 */
union {
struct mgmt_tlv entry; /* 12 3 */
struct {
unsigned char __offset_to_value[3]; /* 12 3 */
/* XXX 1 byte hole, try to pack */
__le16 value; /* 16 2 */
}; /* 12 6 */
} def_page_scan_window; /* 12 6 */
...
}...
So, I need to figure out another solution for this.
Thanks
-Gustavo
On 8/31/25 19:13, Gustavo A. R. Silva wrote:
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
>
> Use the new TRAILING_OVERLAP() helper to fix 31 instances of the
> following type of warnings:
>
> 30 net/bluetooth/mgmt_config.c:16:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> 1 net/bluetooth/mgmt_config.c:22:33: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>
> This helper creates a union between a flexible-array member (FAM)
> and a set of members that would otherwise follow it. This overlays
> the trailing members onto the FAM while preserving the original
> memory layout.
>
> Also, as the structs turn into unions, both members `entry` and
> `value` cannot be statically initialized at once. Create another
> macro to initialize everything after the declaration of `rp`.
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
> net/bluetooth/mgmt_config.c | 97 +++++++++++++++++++------------------
> 1 file changed, 51 insertions(+), 46 deletions(-)
>
> diff --git a/net/bluetooth/mgmt_config.c b/net/bluetooth/mgmt_config.c
> index 6ef701c27da4..829c9cfcea7d 100644
> --- a/net/bluetooth/mgmt_config.c
> +++ b/net/bluetooth/mgmt_config.c
> @@ -12,35 +12,71 @@
> #include "mgmt_config.h"
>
> #define HDEV_PARAM_U16(_param_name_) \
> - struct {\
> - struct mgmt_tlv entry; \
> + TRAILING_OVERLAP(struct mgmt_tlv, entry, value, \
> __le16 value; \
> - } __packed _param_name_
> + ) __packed _param_name_
>
> #define HDEV_PARAM_U8(_param_name_) \
> - struct {\
> - struct mgmt_tlv entry; \
> + TRAILING_OVERLAP(struct mgmt_tlv, entry, value, \
> __u8 value; \
> - } __packed _param_name_
> + ) __packed _param_name_
>
> #define TLV_SET_U16(_param_code_, _param_name_) \
> { \
> - { cpu_to_le16(_param_code_), sizeof(__u16) }, \
> - cpu_to_le16(hdev->_param_name_) \
> + rp._param_name_.entry.type = cpu_to_le16(_param_code_); \
> + rp._param_name_.entry.length = sizeof(__u16); \
> + rp._param_name_.value = cpu_to_le16(hdev->_param_name_); \
> }
>
> #define TLV_SET_U8(_param_code_, _param_name_) \
> { \
> - { cpu_to_le16(_param_code_), sizeof(__u8) }, \
> - hdev->_param_name_ \
> + rp._param_name_.entry.type = cpu_to_le16(_param_code_); \
> + rp._param_name_.entry.length = sizeof(__u8); \
> + rp._param_name_.value = hdev->_param_name_; \
> }
>
> #define TLV_SET_U16_JIFFIES_TO_MSECS(_param_code_, _param_name_) \
> { \
> - { cpu_to_le16(_param_code_), sizeof(__u16) }, \
> - cpu_to_le16(jiffies_to_msecs(hdev->_param_name_)) \
> + rp._param_name_.entry.type = cpu_to_le16(_param_code_); \
> + rp._param_name_.entry.length = sizeof(__u16); \
> + rp._param_name_.value = cpu_to_le16(jiffies_to_msecs(hdev->_param_name_)); \
> }
>
> +#define TLV_SET_ALL() \
> +{ \
> + TLV_SET_U16(0x0000, def_page_scan_type); \
> + TLV_SET_U16(0x0001, def_page_scan_int); \
> + TLV_SET_U16(0x0002, def_page_scan_window); \
> + TLV_SET_U16(0x0003, def_inq_scan_type); \
> + TLV_SET_U16(0x0004, def_inq_scan_int); \
> + TLV_SET_U16(0x0005, def_inq_scan_window); \
> + TLV_SET_U16(0x0006, def_br_lsto); \
> + TLV_SET_U16(0x0007, def_page_timeout); \
> + TLV_SET_U16(0x0008, sniff_min_interval); \
> + TLV_SET_U16(0x0009, sniff_max_interval); \
> + TLV_SET_U16(0x000a, le_adv_min_interval); \
> + TLV_SET_U16(0x000b, le_adv_max_interval); \
> + TLV_SET_U16(0x000c, def_multi_adv_rotation_duration); \
> + TLV_SET_U16(0x000d, le_scan_interval); \
> + TLV_SET_U16(0x000e, le_scan_window); \
> + TLV_SET_U16(0x000f, le_scan_int_suspend); \
> + TLV_SET_U16(0x0010, le_scan_window_suspend); \
> + TLV_SET_U16(0x0011, le_scan_int_discovery); \
> + TLV_SET_U16(0x0012, le_scan_window_discovery); \
> + TLV_SET_U16(0x0013, le_scan_int_adv_monitor); \
> + TLV_SET_U16(0x0014, le_scan_window_adv_monitor); \
> + TLV_SET_U16(0x0015, le_scan_int_connect); \
> + TLV_SET_U16(0x0016, le_scan_window_connect); \
> + TLV_SET_U16(0x0017, le_conn_min_interval); \
> + TLV_SET_U16(0x0018, le_conn_max_interval); \
> + TLV_SET_U16(0x0019, le_conn_latency); \
> + TLV_SET_U16(0x001a, le_supv_timeout); \
> + TLV_SET_U16_JIFFIES_TO_MSECS(0x001b, def_le_autoconnect_timeout); \
> + TLV_SET_U16(0x001d, advmon_allowlist_duration); \
> + TLV_SET_U16(0x001e, advmon_no_filter_duration); \
> + TLV_SET_U8(0x001f, enable_advmon_interleave_scan); \
> +}
> +
> int read_def_system_config(struct sock *sk, struct hci_dev *hdev, void *data,
> u16 data_len)
> {
> @@ -78,40 +114,9 @@ int read_def_system_config(struct sock *sk, struct hci_dev *hdev, void *data,
> HDEV_PARAM_U16(advmon_allowlist_duration);
> HDEV_PARAM_U16(advmon_no_filter_duration);
> HDEV_PARAM_U8(enable_advmon_interleave_scan);
> - } __packed rp = {
> - TLV_SET_U16(0x0000, def_page_scan_type),
> - TLV_SET_U16(0x0001, def_page_scan_int),
> - TLV_SET_U16(0x0002, def_page_scan_window),
> - TLV_SET_U16(0x0003, def_inq_scan_type),
> - TLV_SET_U16(0x0004, def_inq_scan_int),
> - TLV_SET_U16(0x0005, def_inq_scan_window),
> - TLV_SET_U16(0x0006, def_br_lsto),
> - TLV_SET_U16(0x0007, def_page_timeout),
> - TLV_SET_U16(0x0008, sniff_min_interval),
> - TLV_SET_U16(0x0009, sniff_max_interval),
> - TLV_SET_U16(0x000a, le_adv_min_interval),
> - TLV_SET_U16(0x000b, le_adv_max_interval),
> - TLV_SET_U16(0x000c, def_multi_adv_rotation_duration),
> - TLV_SET_U16(0x000d, le_scan_interval),
> - TLV_SET_U16(0x000e, le_scan_window),
> - TLV_SET_U16(0x000f, le_scan_int_suspend),
> - TLV_SET_U16(0x0010, le_scan_window_suspend),
> - TLV_SET_U16(0x0011, le_scan_int_discovery),
> - TLV_SET_U16(0x0012, le_scan_window_discovery),
> - TLV_SET_U16(0x0013, le_scan_int_adv_monitor),
> - TLV_SET_U16(0x0014, le_scan_window_adv_monitor),
> - TLV_SET_U16(0x0015, le_scan_int_connect),
> - TLV_SET_U16(0x0016, le_scan_window_connect),
> - TLV_SET_U16(0x0017, le_conn_min_interval),
> - TLV_SET_U16(0x0018, le_conn_max_interval),
> - TLV_SET_U16(0x0019, le_conn_latency),
> - TLV_SET_U16(0x001a, le_supv_timeout),
> - TLV_SET_U16_JIFFIES_TO_MSECS(0x001b,
> - def_le_autoconnect_timeout),
> - TLV_SET_U16(0x001d, advmon_allowlist_duration),
> - TLV_SET_U16(0x001e, advmon_no_filter_duration),
> - TLV_SET_U8(0x001f, enable_advmon_interleave_scan),
> - };
> + } __packed rp;
> +
> + TLV_SET_ALL();
>
> bt_dev_dbg(hdev, "sock %p", sk);
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-08-31 18:03 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2025-08-31 17:13 [PATCH][next] Bluetooth: Avoid a couple dozen -Wflex-array-member-not-at-end warnings Gustavo A. R. Silva
2025-08-31 18:02 ` Gustavo A. R. Silva
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®