diff options
Diffstat (limited to 'Documentation/trace/kprobetrace.rst')
| -rw-r--r-- | Documentation/trace/kprobetrace.rst | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst index a49662ccd53c..3b6791c17e9b 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 @@ -74,7 +75,7 @@ Function arguments at kretprobe ------------------------------- Function arguments can be accessed at kretprobe using $arg<N> fetcharg. This is useful to record the function parameter and return value at once, and -trace the difference of structure fields (for debuging a function whether it +trace the difference of structure fields (for debugging a function whether it correctly updates the given data structure or not). See the :ref:`sample<fprobetrace_exit_args_sample>` in fprobe event for how it works. @@ -122,6 +123,9 @@ 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 |