tracing: Fix race where eprobes can be called before the event

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix race where eprobes can be called before the event The flag that tells the event to call its triggers after reading the event is set for eprobes after the eprobe is enabled. This leads to a race where the eprobe may be triggered at the beginning of the event where the record information is NULL. The eprobe then dereferences the NULL record causing a NULL kernel pointer bug. Test for a NULL record to keep this from happening.

References

• https://git.kernel.org/stable/c/7291dec4f2d17a2d3fd1f789fb41e58476539f21
• https://git.kernel.org/stable/c/73f5191467ffe3af82f27fe0ea6a8c2fac724d3f
• https://git.kernel.org/stable/c/94eedf3dded5fb472ce97bfaf3ac1c6c29c35d26