From fa17cb4b3b42618aeed1e0bce80cc55106561718 Mon Sep 17 00:00:00 2001 From: Kalesh Singh Date: Wed, 30 Oct 2024 10:17:49 -0700 Subject: [PATCH] tracing: Document tracefs gid mount option 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 Cc: Mathieu Desnoyers Cc: Shuah Khan Cc: Ali Zahraee Cc: Christian Brauner Cc: David Howells Cc: Masami Hiramatsu Link: https://lore.kernel.org/20241030171928.4168869-3-kaleshsingh@google.com Signed-off-by: Kalesh Singh Signed-off-by: Steven Rostedt (Google) --- 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=]] 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"