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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-14 17:03:12 -0800 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2020-02-14 17:19:22 -0800 |
| commit | 3dbae15538972c9e1578cb216964c2840361a538 (patch) | |
| tree | b6d2c378ceca6d49e82f838bc6a0a7120600c4d5 | |
| parent | 94bef5d57992f9e987a9b7e8fa736ee204ac4f7a (diff) | |
| download | linux-3dbae15538972c9e1578cb216964c2840361a538.tar.bz2 | |
Input: cyapa - 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/20200214172132.GA28389@embeddedor
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
| -rw-r--r-- | drivers/input/mouse/cyapa_gen5.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/input/mouse/cyapa_gen5.c b/drivers/input/mouse/cyapa_gen5.c index 14239fbd72cf..7f012bfa2658 100644 --- a/drivers/input/mouse/cyapa_gen5.c +++ b/drivers/input/mouse/cyapa_gen5.c @@ -250,7 +250,7 @@ struct cyapa_tsg_bin_image_data_record { struct cyapa_tsg_bin_image { struct cyapa_tsg_bin_image_head image_head; - struct cyapa_tsg_bin_image_data_record records[0]; + struct cyapa_tsg_bin_image_data_record records[]; } __packed; struct pip_bl_packet_start { @@ -271,7 +271,7 @@ struct pip_bl_cmd_head { u8 report_id; /* Bootloader output report id, must be 40h */ u8 rsvd; /* Reserved, must be 0 */ struct pip_bl_packet_start packet_start; - u8 data[0]; /* Command data variable based on commands */ + u8 data[]; /* Command data variable based on commands */ } __packed; /* Initiate bootload command data structure. */ @@ -300,7 +300,7 @@ struct tsg_bl_metadata_row_params { struct tsg_bl_flash_row_head { u8 flash_array_id; __le16 flash_row_id; - u8 flash_data[0]; + u8 flash_data[]; } __packed; struct pip_app_cmd_head { @@ -314,7 +314,7 @@ struct pip_app_cmd_head { * Bit 6-0: command code. */ u8 cmd_code; - u8 parameter_data[0]; /* Parameter data variable based on cmd_code */ + u8 parameter_data[]; /* Parameter data variable based on cmd_code */ } __packed; /* Application get/set parameter command data structure */ |