INIT_TASK() should initialize ->thread_group list

The trivial /sbin/init doing

	int main(void)
	{
		kill(0, SIGKILL)
	}

crashes the kernel.

This happens because __kill_pgrp_info(init_struct_pid) also sends SIGKILL
to the swapper process which runs with the uninitialized ->thread_group.

Change INIT_TASK() to initialize ->thread_group properly.

Note: the real problem is that the swapper process must not be visible to
signals, see the next patch. But this change is right anyway and fixes
the crash.

Reported-and-tested-by: Mathias Krause <mathias.krause@secunet.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Mathias Krause <Mathias.Krause@secunet.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2010-05-26 14:44:08 -07:00 committed by Linus Torvalds
parent 72680a191b
commit fa2755e20a

View File

@ -163,6 +163,7 @@ extern struct cred init_cred;
[PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID), \
[PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID), \
}, \
.thread_group = LIST_HEAD_INIT(tsk.thread_group), \
.dirties = INIT_PROP_LOCAL_SINGLE(dirties), \
INIT_IDS \
INIT_PERF_EVENTS(tsk) \