AZL-98078

In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: use proper context for logging

The same as the rest of the code, getssinfofromatombios() uses calcpllcs->ctx->logger for logging. But calcpllcs->ctx is initialized only later in calcpllmaxvcoconstruct(). Therefore, any output using DCLOGSYNC() leads to a NULL pointer deference in getssinfofromatombios().

According to Sashiko, the very same problem exists in dce112getpixclkdividers() and dcn3getpixclkdividers() too.

To avoid accessing the NULL context, use clksrc->base.ctx->logger everywhere. That context in base is initialized earlier in dce110clksrcconstruct() and dce112clksrcconstruct(). Before getssinfofromatombios() or Sashiko's getpixclkdividers functions above are actually called. This is done by redefining DC_LOGGER to CTX->logger.

Before: dce110clksrcconstruct() did: -> sets clksrc->base.ctx = ctx; -> ssinfofromatombioscreate() -> getssinfofromatombios() <- uses calcpllcs->ctx # BOOM -> calcpllmaxvcoconstruct() <- sets calcpllcs->ctx

After: dce110clksrcconstruct() does: -> sets clksrc->base.ctx = ctx; -> ssinfofromatombioscreate() -> getssinfofromatombios() <- uses clk_src->base.ctx

(cherry picked from commit 6f16fcbb0c46a87e3d9685407e906573d60104b0)