diff options
| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 22:25:17 +0300 |
|---|---|---|
| committer | Daniel Lezcano <daniel.lezcano@linaro.org> | 2020-05-22 19:45:15 +0300 |
| commit | f740e64c6cd6d9c26b4b9fc0a8d339b215147af7 (patch) | |
| tree | cd997eaea3f09dcec6a71a17381ca022d946e7c7 /drivers/thermal | |
| parent | 1202a442a31fd2e53cde1a9677d9f7005e48fd6e (diff) | |
| download | linux-f740e64c6cd6d9c26b4b9fc0a8d339b215147af7.tar.xz | |
thermal: imx8mm: Replace zero-length array with flexible-array
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]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
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 <gustavoars@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200507192517.GA16557@embeddedor
Diffstat (limited to 'drivers/thermal')
| -rw-r--r-- | drivers/thermal/imx8mm_thermal.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/thermal/imx8mm_thermal.c b/drivers/thermal/imx8mm_thermal.c index 0d60f8d7894f..e6061e26d4ac 100644 --- a/drivers/thermal/imx8mm_thermal.c +++ b/drivers/thermal/imx8mm_thermal.c @@ -54,7 +54,7 @@ struct imx8mm_tmu { void __iomem *base; struct clk *clk; const struct thermal_soc_data *socdata; - struct tmu_sensor sensors[0]; + struct tmu_sensor sensors[]; }; static int imx8mm_tmu_get_temp(void *data, int *temp) |