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-rw-r--r--Documentation/trace/kprobetrace.rst4
1 files changed, 3 insertions, 1 deletions
diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index 0d103074d3d2..651f9ab53f3e 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -58,7 +58,7 @@ 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", "symbol", "symstr"
+ (x8/x16/x32/x64), "char", "string", "ustring", "symbol", "symstr"
and bitfield are supported.
(\*1) only for the probe on function entry (offs == 0).
@@ -82,6 +82,8 @@ Note that the array can be applied to memory type fetchargs, you can not
apply it to registers/stack-entries etc. (for example, '$stack1:x8[8]' is
wrong, but '+8($stack):x8[8]' is OK.)
+Char type can be used to show the character value of traced arguments.
+
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. "ustring" type is an alternative of string for user-space.