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This > worked. Do you have any suggestions for alternatives? IMHO, deferred execution of TP_printk() code in kernel context is a fundamental mistake causing all those problems. This opens the door to store pointers to strings (or anything else really) that sit in kernel modules which can be unloaded between tracing and TP_printk() execution, or as we are seeing here pointers to data which can be mapped at different addresses across kernel reboot, into the ring buffer. If TP_printk() don't have access to load data from random kernel memory in the first place, and can only read from the buffer, we would not be having those misuses, and there would be nothing to work-around as the strings/data would all be serialized into the ring buffer. In LTTng we've taken the approach to only read the trace data at post-processing from user-space (we don't have the equivalent of TP_printk(), and that's on purpose). I wonder if we could keep the ftrace trace_pipe pretty-printing behavior, while isolating the TP_printk() execution into a userspace process which would only map the ring buffer ? This way, users trying to misuse TP_printk() would get immediate feedback about their mistake because they cannot print the trace. We could print a dmesg warning about crash of a usermode helper program, for instance. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com