diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2022-01-14 02:08:40 +0100 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2022-01-14 09:42:24 +0100 |
| commit | f37c3bbc635994eda203a6da4ba0f9d05165a8d6 (patch) | |
| tree | 0d0cd245f1558617503c7f61dd9f426ff6200d6e /Documentation/trace | |
| parent | rtla: Add rtla timerlat hist documentation (diff) | |
| download | linux-f37c3bbc635994eda203a6da4ba0f9d05165a8d6.tar.xz linux-f37c3bbc635994eda203a6da4ba0f9d05165a8d6.zip | |
tracing: Add ustring operation to filtering string pointers
Since referencing user space pointers is special, if the user wants to
filter on a field that is a pointer to user space, then they need to
specify it.
Add a ".ustring" attribute to the field name for filters to state that the
field is pointing to user space such that the kernel can take the
appropriate action to read that pointer.
Link: https://lore.kernel.org/all/yt9d8rvmt2jq.fsf@linux.ibm.com/
Fixes: 77360f9bbc7e ("tracing: Add test for user space strings when filtering on string pointers")
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/events.rst | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/trace/events.rst b/Documentation/trace/events.rst index 45e66a60a816..c47f381d0c00 100644 --- a/Documentation/trace/events.rst +++ b/Documentation/trace/events.rst @@ -198,6 +198,15 @@ The glob (~) accepts a wild card character (\*,?) and character classes prev_comm ~ "*sh*" prev_comm ~ "ba*sh" +If the field is a pointer that points into user space (for example +"filename" from sys_enter_openat), then you have to append ".ustring" to the +field name:: + + filename.ustring ~ "password" + +As the kernel will have to know how to retrieve the memory that the pointer +is at from user space. + 5.2 Setting filters ------------------- |