When a module's init text is freed, do_init_module() calls
ftrace_free_mem() with a half-open [start, end) range.  However the
ftrace_cmp_recs() comparator treats the upper bound as inclusive, as all
its other users do, passing 'ip + size - 1'.  So ftrace_free_mem() can
delete a record sitting exactly at 'end', which is outside the freed
range.

For a kernel without CFI or IBT, the first record of a function is at
the function start, which for the first function in a module is also the
base of its text allocation.  As the module allocator packs its regions,
that address is often the 'end' passed by a neighboring module's
do_init_module(), causing the first function's ftrace location to get
disabled, preventing an attempt to livepatch it:

  livepatch: failed to find location for function 'pcspkr_probe'

Convert the exclusive end to the inclusive 'end - 1' the comparator
expects, and return early for an empty range to avoid the subtraction
from underflowing when the init text size is zero.

Cc: stable@vger.kernel.org
Fixes: 42c269c88dc1 ("ftrace: Allow for function tracing to record init functions on boot up")
Link: https://patch.msgid.link/1b5ccfa8095bdb1277f84af1c2c2e2205aca03ae.1785992188.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-4-leon.hwang@linux.dev
Fixes: e93672f770d7 ("ftrace: Add update_ftrace_direct_mod function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-3-leon.hwang@linux.dev
Fixes: 8d2c1233f371 ("ftrace: Add update_ftrace_direct_del function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-2-leon.hwang@linux.dev
Fixes: d05cb470663a ("ftrace: Fix modification of direct_function hash while in use")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

In ftrace, the trace_parser structure is allocated and initialized when
a trace file is opened, and is subsequently used across write and release
handlers to parse user input.

The affected handler paths and their specific functions are:
  - Open paths: ftrace_regex_open(), ftrace_graph_open()
  - Write paths: ftrace_regex_write(), ftrace_graph_write()
  - Release paths: ftrace_regex_release(), ftrace_graph_release()

If userspace opens a trace file descriptor and shares it across multiple
threads, concurrent write calls will race on the parser's internal state,
specifically the 'idx', 'cont', and 'buffer' fields, leading to corrupted
input or undefined behavior.

Fix this by adding a global mutex, parser_lock, to serialize all access
to trace_parser across write and release paths, preventing concurrent
corruption of parser state.

Fixes: e704eff3ff51 ("ftrace: Have set_graph_function handle multiple functions in one write")
Fixes: 689fd8b65d66 ("tracing: trace parser support for function and graph")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260725024721.1983675-1-wutengda@huaweicloud.com
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Renaming __add_hash_entry to add_ftrace_hash_entry and making it global,
it will be used in following changes outside ftrace.c object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adding ftrace_hash_remove function that removes all entries
from struct ftrace_hash object without freeing them.

It will be used in following changes where entries are allocated
as part of another structure and are free-ed separately.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adding external ftrace_hash_count function so we could get hash
count outside of ftrace object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Pull tracing updates from Steven Rostedt:

 - Fix printf format warning for bprintf

   sunrpc uses a trace_printk() that triggers a printf warning during
   the compile. Move the __printf() attribute around for when debugging
   is not enabled the warning will go away

 - Remove redundant check for EVENT_FILE_FL_FREED in
   event_filter_write()

   The FREED flag is checked in the call to event_file_file() and then
   checked again right afterward, which is unneeded

 - Clean up event_file_file() and event_file_data() helpers

   These helper functions played a different role in the past, but now
   with eventfs, the READ_ONCE() isn't needed. Simplify the code a bit
   and also add a warning to event_file_data() if the file or its data
   is not present

 - Remove updating file->private_data in tracing open

   All access to the file private data is handled by the helper
   functions, which do not use file->private_data. Stop updating it on
   open

 - Show ENUM names in function arguments via BTF in function tracing

   When showing the function arguments when func-args option is set for
   function tracing, if one of the arguments is found to be an enum,
   show the name of the enum instead of its number

 - Add new trace_call__##name() API for tracepoints

   Tracepoints are enabled via static_branch() blocks, where when not
   enabled, there's only a nop that is in the code where the execution
   will just skip over it. When tracing is enabled, the nop is converted
   to a direct jump to the tracepoint code. Sometimes more calculations
   are required to be performed to update the parameters of the
   tracepoint. In this case, trace_##name##_enabled() is called which is
   a static_branch() that gets enabled only when the tracepoint is
   enabled. This allows the extra calculations to also be skipped by the
   nop:

	if (trace_foo_enabled()) {
		x = bar();
		trace_foo(x);
	}

   Where the x=bar() is only performed when foo is enabled. The problem
   with this approach is that there's now two static_branch() calls. One
   for checking if the tracepoint is enabled, and then again to know if
   the tracepoint should be called. The second one is redundant

   Introduce trace_call__foo() that will call the foo() tracepoint
   directly without doing a static_branch():

	if (trace_foo_enabled()) {
		x = bar();
		trace_call__foo();
	}

 - Update various locations to use the new trace_call__##name() API

 - Move snapshot code out of trace.c

   Cleaning up trace.c to not be a "dump all", move the snapshot code
   out of it and into a new trace_snapshot.c file

 - Clean up some "%*.s" to "%*s"

 - Allow boot kernel command line options to be called multiple times

   Have options like:

	ftrace_filter=foo ftrace_filter=bar ftrace_filter=zoo

   Equal to:

	ftrace_filter=foo,bar,zoo

 - Fix ipi_raise event CPU field to be a CPU field

   The ipi_raise target_cpus field is defined as a __bitmask(). There is
   now a __cpumask() field definition. Update the field to use that

 - Have hist_field_name() use a snprintf() and not a series of strcat()

   It's safer to use snprintf() that a series of strcat()

 - Fix tracepoint regfunc balancing

   A tracepoint can define a "reg" and "unreg" function that gets called
   before the tracepoint is enabled, and after it is disabled
   respectively. But on error, after the "reg" func is called and the
   tracepoint is not enabled, the "unreg" function is not called to tear
   down what the "reg" function performed

 - Fix output that shows what histograms are enabled

   Event variables are displayed incorrectly in the histogram output

   Instead of "sched.sched_wakeup.$var", it is showing
   "$sched.sched_wakeup.var" where the '$' is in the incorrect location

 - Some other simple cleanups

* tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (24 commits)
  selftests/ftrace: Add test case for fully-qualified variable references
  tracing: Fix fully-qualified variable reference printing in histograms
  tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()
  tracing: Rebuild full_name on each hist_field_name() call
  tracing: Report ipi_raise target CPUs as cpumask
  tracing: Remove duplicate latency_fsnotify() stub
  tracing: Preserve repeated trace_trigger boot parameters
  tracing: Append repeated boot-time tracing parameters
  tracing: Remove spurious default precision from show_event_trigger/filter formats
  cpufreq: Use trace_call__##name() at guarded tracepoint call sites
  tracing: Remove tracing_alloc_snapshot() when snapshot isn't defined
  tracing: Move snapshot code out of trace.c and into trace_snapshot.c
  mm: damon: Use trace_call__##name() at guarded tracepoint call sites
  btrfs: Use trace_call__##name() at guarded tracepoint call sites
  spi: Use trace_call__##name() at guarded tracepoint call sites
  i2c: Use trace_call__##name() at guarded tracepoint call sites
  kernel: Use trace_call__##name() at guarded tracepoint call sites
  tracepoint: Add trace_call__##name() API
  tracing: trace_mmap.h: fix a kernel-doc warning
  tracing: Pretty-print enum parameters in function arguments
  ...

When ftrace_lookup_symbols() is called with a single symbol (cnt == 1),
use kallsyms_lookup_name() for O(log N) binary search instead of the
full linear scan via kallsyms_on_each_symbol().

ftrace_lookup_symbols() was designed for batch resolution of many
symbols in a single pass.  For large cnt this is efficient: a single
O(N) walk over all symbols with O(log cnt) binary search into the
sorted input array.  But for cnt == 1 it still decompresses all ~200K
kernel symbols only to match one.

kallsyms_lookup_name() uses the sorted kallsyms index and needs only
~17 decompressions for a single lookup.

This is the common path for kprobe.session with exact function names,
where libbpf sends one symbol per BPF_LINK_CREATE syscall.

If binary lookup fails (duplicate symbol names where the first match
is not ftrace-instrumented), the function falls through to the existing
linear scan path.

Before (cnt=1, 50 kprobe.session programs):
  Attach: 858 ms  (kallsyms_expand_symbol 25% of CPU)

After:
  Attach:  52 ms  (16x faster)

Cc: <bpf@vger.kernel.org>
Link: https://patch.msgid.link/20260302200837.317907-3-andrey.grodzovsky@crowdstrike.com
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>