Commit ee7f3666995d ("tracefs: Have new files inherit the ownership
of their parent") and commit 48b27b6b5191 ("tracefs: Set all files to
the same group ownership as the mount option") introduced a new gid
mount option that allows specifying a group to apply to all entries
in tracefs.
Document this in the tracing readme.
Cc: Eric Sandeen <sandeen@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
---
Changes in v2:
- Reference commits instead of lore links, per Steve
kernel/trace/trace.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a8f52b6527ca..2b64b3ec67d9 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5501,6 +5501,10 @@ static const struct file_operations tracing_iter_fops = {
static const char readme_msg[] =
"tracing mini-HOWTO:\n\n"
+ "By default tracefs removes all OTH file permission bits.\n"
+ "When mounting tracefs an optional group id can be specified\n"
+ "which adds the group to every directory and file in tracefs:\n\n"
+ "\t e.g. mount -t tracefs [-o [gid=<gid>]] nodev /sys/kernel/tracing\n\n"
"# echo 0 > tracing_on : quick way to disable tracing\n"
"# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
" Important files:\n"
--
2.47.0.163.g1226f6d8fa-goog
