diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2006-03-28 16:11:09 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-28 18:36:41 -0800 |
| commit | c7c6464117a02b0d54feb4ebeca4db70fa493678 (patch) | |
| tree | 903498de6685d769631edbd7bce7609d07365946 /include | |
| parent | 73b9ebfe126a4a886ee46cbab637374d7024668a (diff) | |
[PATCH] pidhash: don't use zero pids
daemonize() calls set_special_pids(1,1), while init and kernel threads spawned
from init/main.c:init() run with 0,0 special pids. This patch changes
INIT_SIGNALS() so that that they run with ->pgrp == ->session == 1 also. This
patch relies on fact that swapper's pid == 1.
Now we have no hashed zero pids in pid_hash[].
User-space visibible change is that now /sbin/init runs with (1,1) special
pids and becomes a session leader.
Quoting Eric W. Biederman:
>
> daemonize consuming pids (1,1) then consumes pgrp 1. So that when
> /sbin/init calls setsid() it thinks /sbin/init is a process group
> leader and setsid() fails. So /sbin/init wants pgrp 1 session 1
> but doesn't get it. I am pretty certain daemonize did not exist so
> /sbin/init got pgrp 1 session 1 in 2.4.
>
> That is the bug that is being fixed.
>
> This patch takes things one step farther and essentially calls
> setsid() for pid == 1 before init is execed. That is new behavior
> but it cleans up the kernel as we now do not need to support the
> case of a process without a process group or a session.
>
> The only process that could have possibly cared was /sbin/init
> and it already calls setsid() because it doesn't want that.
>
> If this was going to break anything noticeable the change in behavior
> from 2.4 to 2.6 would have already done that.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/init_task.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 92146f3b742..41ecbb847f3 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -62,6 +62,8 @@ .posix_timers = LIST_HEAD_INIT(sig.posix_timers), \ .cpu_timers = INIT_CPU_TIMERS(sig.cpu_timers), \ .rlim = INIT_RLIMITS, \ + .pgrp = 1, \ + .session = 1, \ } #define INIT_SIGHAND(sighand) { \ |