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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-01-16 16:03:27 -0600 |
---|---|---|
committer | Johan Hovold <johan@kernel.org> | 2020-01-17 11:44:23 +0100 |
commit | 50c3c5e1c1b000d6a321ffdc0003bc6b7ac0b0e5 (patch) | |
tree | efea0e6b4557ac18e8e1d99c38727283998bd85f | |
parent | e6421583953fd92eba1785f90b228d70345125d6 (diff) | |
download | linux-50c3c5e1c1b000d6a321ffdc0003bc6b7ac0b0e5.tar.bz2 |
USB: serial: garmin_gps: Use flexible-array member
Old code in the kernel uses 1-byte and 0-byte arrays to indicate the
presence of a "variable length array":
struct something {
int length;
u8 data[1];
};
struct something *instance;
instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL);
instance->length = size;
memcpy(instance->data, source, size);
There is also 0-byte arrays. Both cases pose confusion for things like
sizeof(), CONFIG_FORTIFY_SOURCE, etc.[1] Instead, the preferred mechanism
to declare variable-length types such as the one above is a flexible array
member[2] which need to be the last member of a structure and empty-sized:
struct something {
int stuff;
u8 data[];
};
Also, 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
unadvertenly introduced[3] to the codebase from now on.
[1] https://github.com/KSPP/linux/issues/21
[2] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
-rw-r--r-- | drivers/usb/serial/garmin_gps.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c index 633550ec3025..ffd984142171 100644 --- a/drivers/usb/serial/garmin_gps.c +++ b/drivers/usb/serial/garmin_gps.c @@ -104,7 +104,7 @@ struct garmin_packet { int seq; /* the real size of the data array, always > 0 */ int size; - __u8 data[1]; + __u8 data[]; }; /* structure used to keep the current state of the driver */ |