kernel/trace/ftrace.c in the Linux kernel before 2.6.35.5, when debugfs is enabled, does not properly handle interaction between mutex possession and llseek…

kernel/trace/ftrace.c in the Linux kernel before 2.6.35.5, when debugfs is enabled, does not properly handle interaction between mutex possession and llseek operations, which allows local users to cause a denial of service (NULL pointer dereference and outage of all function tracing files) via an lseek call on a file descriptor associated with the set_ftrace_filter file.