In the Linux kernel, the following vulnerability has been resolved: dmaengine: fsl-edma: tracing...

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

dmaengine: fsl-edma: tracing: no ptr dereference during log output

The fsl edma events store a pointer to a struct fsl_edma_engine in the ringbuffer and dereference it when a log entry is printed. At this time, the pointer may no longer be valid.

Event injection can be used to trigger a crash:

$ cd /sys/kernel/tracing $ echo 'value = 0' > events/fsl_edma/edma_writeb/inject $ cat trace

The log output needs only edma->membase. Add a membase field at the end of the event and use the new field for log output. Keep the existing fields for backward compatibility.