The call of mxc_jpeg_get_plane_size() from mxc_jpeg_dec_irq() sets
plane_no argument to 1. The compiler sees that it's possible to end up
with an access beyond the bounds of sizeimage, if mem_planes was too
large:
if (plane_no >= fmt->mem_planes) // mem_planes = 2+
return 0;
if (fmt->mem_planes == fmt->comp_planes) // comp_planes != mem_planes
return q_data->sizeimage[plane_no];
comp_planes == 0 or 1 is safe. comp_planes > 2 would be out of bounds.
(This isn't currently possible given the contents of mxc_formats, though.)
Silence the warning by bounds checking comp_planes for future
robustness. Seen with GCC 13:
In function 'mxc_jpeg_get_plane_size',
inlined from 'mxc_jpeg_dec_irq' at ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c:729:14:
../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c:641:42: warning: array subscript 2 is above array bounds of 'u32[2]' {aka 'unsigned int[2]'} [-Warray-bounds=]
641 | size += q_data->sizeimage[i];
| ~~~~~~~~~~~~~~~~~^~~
In file included from ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.h:112,
from ../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c:63:
../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h: In function 'mxc_jpeg_dec_irq':
../drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h:84:41: note: while referencing 'sizeimage'
84 | u32 sizeimage[MXC_JPEG_MAX_PLANES];
| ^~~~~~~~~