Merge tag 'trace-probes-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull trace probes updates from Steven Rostedt:

 - New "symstr" type for dynamic events that writes the name of the
   function+offset into the ring buffer and not just the address

 - Prevent kernel symbol processing on addresses in user space probes
   (uprobes).

 - And minor fixes and clean ups

* tag 'trace-probes-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Reject symbol/symstr type for uprobe
  tracing/probes: Add symstr type for dynamic events
  kprobes: kretprobe events missing on 2-core KVM guest
  kprobes: Fix check for probe enabled in kill_kprobe()
  test_kprobes: Fix implicit declaration error of test_kprobes
  tracing: Fix race where eprobes can be called before the event

2 files changed, 7 insertions, 4 deletions

diff --git a/Documentation/trace/kprobes.rst b/Documentation/trace/kprobes.rst
index 48cf778a2468..fc7ce76eab65 100644
--- a/Documentation/trace/kprobes.rst
+++ b/Documentation/trace/kprobes.rst
@@ -131,8 +131,7 @@ For example, if the function is non-recursive and is called with a
 spinlock held, maxactive = 1 should be enough.  If the function is
 non-recursive and can never relinquish the CPU (e.g., via a semaphore
 or preemption), NR_CPUS should be enough.  If maxactive <= 0, it is
-set to a default value.  If CONFIG_PREEMPT is enabled, the default
-is max(10, 2*NR_CPUS).  Otherwise, the default is NR_CPUS.
+set to a default value: max(10, 2*NR_CPUS).
 
 It's not a disaster if you set maxactive too low; you'll just miss
 some probes.  In the kretprobe struct, the nmissed field is set to
diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index 4274cc6a2f94..08a2a6a3782f 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -58,8 +58,8 @@ Synopsis of kprobe_events
   NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
   FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
 		  (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
-		  (x8/x16/x32/x64), "string", "ustring" and bitfield
-		  are supported.
+		  (x8/x16/x32/x64), "string", "ustring", "symbol", "symstr"
+                  and bitfield are supported.
 
   (\*1) only for the probe on function entry (offs == 0).
   (\*2) only for return probe.
@@ -96,6 +96,10 @@ offset, and container-size (usually 32). The syntax is::
 
 Symbol type('symbol') is an alias of u32 or u64 type (depends on BITS_PER_LONG)
 which shows given pointer in "symbol+offset" style.
+On the other hand, symbol-string type ('symstr') converts the given address to
+"symbol+offset/symbolsize" style and stores it as a null-terminated string.
+With 'symstr' type, you can filter the event with wildcard pattern of the
+symbols, and you don't need to solve symbol name by yourself.
 For $comm, the default type is "string"; any other type is invalid.
 
 .. _user_mem_access: