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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 16:29:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-23 21:18:54 +0300 |
| commit | 5979afa2c4d1c8acce28a176ebe27ea13265626a (patch) | |
| tree | a4713b48315ba2506284f2e376c65ff0af3c871b /drivers/staging/gdm724x | |
| parent | cf7e44daa727bf4868a4b3be380829db52a2762d (diff) | |
| download | linux-5979afa2c4d1c8acce28a176ebe27ea13265626a.tar.xz | |
staging: Replace zero-length array with flexible-array member
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>
Link: https://lore.kernel.org/r/20200220132908.GA30501@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/gdm724x')
| -rw-r--r-- | drivers/staging/gdm724x/gdm_mux.h | 2 | ||||
| -rw-r--r-- | drivers/staging/gdm724x/hci_packet.h | 6 |
2 files changed, 4 insertions, 4 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 { |