[PATCH v2 1/3] tracing: document "string_size" [ku]probe type

From: Omar Sandoval
Date: Thu Jun 02 2016 - 21:11:32 EST


From: Omar Sandoval <osandov@xxxxxx>

It has been undocumented since it was introduced in commit e09c8614b329
("tracing/kprobes: Support "string" type").

Signed-off-by: Omar Sandoval <osandov@xxxxxx>
---
Documentation/trace/kprobetrace.txt | 11 ++++++-----
Documentation/trace/uprobetracer.txt | 9 +++++----
2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index d68ea5fc812b..4b3f5293b7bf 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -43,8 +43,8 @@ Synopsis of kprobe_events
+|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
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), "string" and bitfield
- are supported.
+ (u8/u16/u32/u64/s8/s16/s32/s64), "string", "string_size", and
+ bitfield are supported.

(*) only for return probe.
(**) this is useful for fetching a field of data structures.
@@ -54,9 +54,10 @@ Types
Several types are supported for fetch-args. Kprobe tracer will access memory
by given type. Prefix 's' and 'u' means those types are signed and unsigned
respectively. Traced arguments are shown in decimal (signed) or hex (unsigned).
-String type is a special type, which fetches a "null-terminated" string from
-kernel space. This means it will fail and store NULL if the string container
-has been paged out.
+"string" is a special type which fetches a null-terminated string from kernel
+space. This means it will fail and store NULL if the string container has been
+paged out. "string_size" is the length of a null-terminated string including
+the NUL byte.
Bitfield is another special type, which takes 3 parameters, bit-width, bit-
offset, and container-size (usually 32). The syntax is;

diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt
index f1cf9a34ad9d..7e0480263c2f 100644
--- a/Documentation/trace/uprobetracer.txt
+++ b/Documentation/trace/uprobetracer.txt
@@ -39,8 +39,8 @@ Synopsis of uprobe_tracer
+|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
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), "string" and bitfield
- are supported.
+ (u8/u16/u32/u64/s8/s16/s32/s64), "string",
+ "string_size", and bitfield are supported.

(*) only for return probe.
(**) this is useful for fetching a field of data structures.
@@ -50,8 +50,9 @@ Types
Several types are supported for fetch-args. Uprobe tracer will access memory
by given type. Prefix 's' and 'u' means those types are signed and unsigned
respectively. Traced arguments are shown in decimal (signed) or hex (unsigned).
-String type is a special type, which fetches a "null-terminated" string from
-user space.
+"string" is a special type which fetches a null-terminated string from user
+space. "string_size" is the length of a null-terminated string including the
+NUL byte.
Bitfield is another special type, which takes 3 parameters, bit-width, bit-
offset, and container-size (usually 32). The syntax is;

--
2.8.3