Merge tag 'trace-v6.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

- Initialize hash variables in ftrace subops logic

The fix that simplified the ftrace subops logic opened a path where
some variables could be used without being initialized, and done
subtly where the compiler did not catch it. Initialize those
variables to the EMPTY_HASH, which is the default hash.

- Reinitialize the hash pointers after they are freed

Some of the hash pointers in the subop logic were freed but may still
be referenced later. To prevent use-after-free bugs, initialize them
back to the EMPTY_HASH.

- Free the ftrace hashes when they are replaced

The fix that simplified the subops logic updated some hash pointers,
but left the original hash that they were pointing to where they are
no longer used. This caused a memory leak. Free the hashes that are
pointed to by the pointers when they are replaced.

- Fix size initialization of ftrace direct function hash

The ftrace direct function hash used by BPF initialized the hash size
incorrectly. It checked the size of items to a hard coded 32, which
made the hash bit size of 5. The hash size is supposed to be limited
by the bit size of the hash, as the bitmask is allowed to be greater
than 5. Rework the size check to first pass the number of elements to
fls() and then compare that to FTRACE_HASH_MAX_BITS before allocating
the hash.

- Fix format output of ftrace_graph_ent_entry event

The field depth of the ftrace_graph_ent_entry event is of size 4 but
the output showed it as unsigned long and use "%lu". Change it to
unsigned int and use "%u" in the print format that is displayed to
user space.

- Fix the trace event filter on strings

Events can be filtered on numbers or string values. The return value
checked from strncpy_from_kernel_nofault() and
strncpy_from_user_nofault() was used to determine if reading the
strings would fault or not. It would return fault if the value was
non zero, which is basically meant that it was always considering the
read as a fault.

- Add selftest to test trace event string filtering

In order to catch the breakage of the string filtering, add a self
test to make sure that it continues to work.

* tag 'trace-v6.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: selftests: Add testing a user string to filters
tracing: Fix filter string testing
ftrace: Fix type of ftrace_graph_ent_entry.depth
ftrace: fix incorrect hash size in register_ftrace_direct()
ftrace: Free ftrace hashes after they are replaced in the subops code
ftrace: Reinitialize hash to EMPTY_HASH after freeing
ftrace: Initialize variables for ftrace_startup/shutdown_subops()