ptrace: permit ptracing of /sbin/init
Afaics, currently there are no kernel problems with ptracing init, it can't
lose SIGNAL_UNKILLABLE flag and be killed/stopped by accident.
The ability to strace/debug init can be very useful if you try to figure out
why it does not work as expected.
However, admin should know what he does, "gdb /sbin/init 1" stops init, it
can't reap orphaned zombies or take care of /etc/inittab until continued. It
is even possible to crash init (and thus the whole system) if you wish,
ptracer has full control.
See also the long discussion: http://marc.info/?t=120628018600001
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 5f8d452..dcc199c 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -168,8 +168,6 @@
audit_ptrace(task);
retval = -EPERM;
- if (task->pid <= 1)
- goto out;
if (same_thread_group(task, current))
goto out;
@@ -521,12 +519,6 @@
{
struct task_struct *child;
- /*
- * Tracing init is not allowed.
- */
- if (pid == 1)
- return ERR_PTR(-EPERM);
-
read_lock(&tasklist_lock);
child = find_task_by_vpid(pid);
if (child)