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| author | Nathan Chancellor <natechancellor@gmail.com> | 2020-05-27 10:11:49 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-06-11 19:19:15 +0300 |
| commit | bacefb07661733b64cb92fa7037baa1bbbf901e3 (patch) | |
| tree | 311778d94f0631930e6bd4fd690e00e025565475 /drivers | |
| parent | 541f681340c4248ce49f4dbaa64ce227914ad5e7 (diff) | |
| download | linux-bacefb07661733b64cb92fa7037baa1bbbf901e3.tar.xz | |
media: atomisp: Avoid overflow in compute_blending
Clang warns:
drivers/staging/media/atomisp/pci/isp/kernels/xnr/xnr_3.0/ia_css_xnr3.host.c:129:35:
warning: implicit conversion from 'unsigned long' to 'int32_t' (aka
'int') changes value from 18446744073709543424 to -8192
[-Wconstant-conversion]
return MAX(MIN(isp_strength, 0), -XNR_BLENDING_SCALE_FACTOR);
~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
XNR_BLENDING_SCALE_FACTOR is BIT(13), or 8192, which will easily fit
into a signed 32-bit integer. However, it is an unsigned long, which
means that negating it is the same as subtracting that value from
ULONG_MAX + 1, which causes it to be larger than a signed 32-bit
integer so it gets implicitly converted.
We can avoid this by using the variable isp_scale, which holds the value
of XNR_BLENDING_SCALE_FACTOR already, where the implicit conversion from
unsigned long to s32 already happened. If that were to ever overflow,
clang would warn: https://godbolt.org/z/EeSxLG
Link: https://github.com/ClangBuiltLinux/linux/issues/1036
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/staging/media/atomisp/pci/isp/kernels/xnr/xnr_3.0/ia_css_xnr3.host.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/staging/media/atomisp/pci/isp/kernels/xnr/xnr_3.0/ia_css_xnr3.host.c b/drivers/staging/media/atomisp/pci/isp/kernels/xnr/xnr_3.0/ia_css_xnr3.host.c index a9db6366d20b..629f07faf20a 100644 --- a/drivers/staging/media/atomisp/pci/isp/kernels/xnr/xnr_3.0/ia_css_xnr3.host.c +++ b/drivers/staging/media/atomisp/pci/isp/kernels/xnr/xnr_3.0/ia_css_xnr3.host.c @@ -126,7 +126,7 @@ compute_blending(int strength) * exactly as s0.11 fixed point, but -1.0 can. */ isp_strength = -(((strength * isp_scale) + offset) / host_scale); - return MAX(MIN(isp_strength, 0), -XNR_BLENDING_SCALE_FACTOR); + return MAX(MIN(isp_strength, 0), -isp_scale); } void |