[PATCH v8 3/5] Documentation: tracing: add new type '%pd' and '%pD' for kprobe

Ye Bin
2024-03-22T06:42:05Z

Similar to printk() '%pd' is for fetch dentry's name from struct dentry's
pointer, and '%pD' is for fetch file's name from struct file's pointer.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
Documentation/trace/kprobetrace.rst | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index bf9cecb69fc9..f13f0fc11251 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -58,8 +58,9 @@ 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), "char", "string", "ustring", "symbol", "symstr"
- and bitfield are supported.
+ (x8/x16/x32/x64), VFS layer common type(%pd/%pD), "char",
+ "string", "ustring", "symbol", "symstr" and bitfield are
+ supported.

(\*1) only for the probe on function entry (offs == 0). Note, this argument access
is best effort, because depending on the argument type, it may be passed on
@@ -113,6 +114,9 @@ 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.

+VFS layer common type(%pd/%pD) is a special type, which fetches dentry's or
+file's name from struct dentry's address or struct file's address.
+
.. _user_mem_access:

User Memory Access
--
2.31.1