rcu: Fix rcu_torture_read ftrace event

stable inclusion
from stable-v5.10.177
commit a484f8bec8ee33e596d6936241bb397e76144ef8
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I88YNP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a484f8bec8ee33e596d6936241bb397e76144ef8



--------------------------------

commit d18a0415 upstream.

Fix the rcutorturename field so that its size is correctly reported in
the text format embedded in trace.dat files. As it stands, it is
reported as being of size 1:

    field:char rcutorturename[8];   offset:8;       size:1; signed:0;

Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: stable@vger.kernel.org
Fixes: 04ae87a5 ("ftrace: Rework event_create_dir()")
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
[ boqun: Add "Cc" and "Fixes" tags per Steven ]
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>