is_global_init() called on global init sub-thread

Hello,

re-upping https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html

Oleg Nesterov wrote:

:Because is_global_init() is only true for the main thread of /sbin/init. :
:Just look at oom_unkillable_task(). It tries to not kill init. But, say, :select_bad_process() can happily find a sub-thread of is_global_init() :and still kill it.

this is still the case, isn't it? at least in some -stable kernels. is there (or was there) any reason this change has never been committed? (I'm particularly interested in is_global_init()).

static inline int is_global_init(struct task_struct *tsk) {

(quoted diff) +1 -1

-	return tsk->pid == 1;
+	return task_tgid_nr(tsk) == 1;
 }

	-ss

Quoted 10 lines

re-upping https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html

Oleg Nesterov wrote:

:Because is_global_init() is only true for the main thread of /sbin/init. :
:Just look at oom_unkillable_task(). It tries to not kill init. But, say, :select_bad_process() can happily find a sub-thread of is_global_init() :and still kill it.

Quoted 3 lines

this is still the case, isn't it? at least in some -stable kernels. is there (or was there) any reason this change has never been committed? (I'm particularly interested in is_global_init()).

... seems like it makes sense. Can you remind us which init you're having to deal with?

Quoted 5 lines

static inline int is_global_init(struct task_struct *tsk) {

(quoted diff) +1 -1

-	return tsk->pid == 1;
+	return task_tgid_nr(tsk) == 1;
 }

Quoted 14 lines · Serge E. Hallyn

Quoted 13 lines

re-upping https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html

Oleg Nesterov wrote:

:Because is_global_init() is only true for the main thread of /sbin/init. :
:Just look at oom_unkillable_task(). It tries to not kill init. But, say, :select_bad_process() can happily find a sub-thread of is_global_init() :and still kill it.

this is still the case, isn't it? at least in some -stable kernels. is there (or was there) any reason this change has never been committed? (I'm particularly interested in is_global_init()).

Quoted 3 lines

... seems like it makes sense. Can you remind us which init you're having to deal with?

systemd

	-ss

Quoted 19 lines · Sergey Senozhatsky

Quoted 17 lines · Serge E. Hallyn

Quoted 10 lines

re-upping https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html

Oleg Nesterov wrote:

:Because is_global_init() is only true for the main thread of /sbin/init. :
:Just look at oom_unkillable_task(). It tries to not kill init. But, say, :select_bad_process() can happily find a sub-thread of is_global_init() :and still kill it.

Quoted 3 lines

this is still the case, isn't it? at least in some -stable kernels. is there (or was there) any reason this change has never been committed? (I'm particularly interested in is_global_init()).

... seems like it makes sense. Can you remind us which init you're having to deal with?

Quoted 3 lines

systemd

	-ss

Well it makes sense to me. The question is whether we are protecting the thing running as init, or the 'physical' thread with pid 1. I think it's the former, so let's push on this. Please resend the patch with a proper signed-off-by, and feel free to add

Acked-by Serge Hallyn <[email protected]>

Quoted 24 lines · Serge E. Hallyn

Quoted 22 lines · Sergey Senozhatsky

Quoted 10 lines · Serge E. Hallyn

Quoted 10 lines

re-upping https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html

Oleg Nesterov wrote:

:Because is_global_init() is only true for the main thread of /sbin/init. :
:Just look at oom_unkillable_task(). It tries to not kill init. But, say, :select_bad_process() can happily find a sub-thread of is_global_init() :and still kill it.

Quoted 7 lines

Quoted 3 lines

this is still the case, isn't it? at least in some -stable kernels. is there (or was there) any reason this change has never been committed? (I'm particularly interested in is_global_init()).

... seems like it makes sense. Can you remind us which init you're having to deal with?

systemd

	-ss

Quoted 4 lines

Well it makes sense to me. The question is whether we are protecting the thing running as init, or the 'physical' thread with pid 1. I think it's the former, so let's push on this. Please resend the patch with a proper signed-off-by, and feel free to add

thanks. a bit puzzled, would reported-by Oleg and suggested-by Richard be appropriate?

(no objections if Oleg or Richard will submit it).

Quoted 1 line

Acked-by Serge Hallyn <[email protected]>

	-ss

Quoted 24 lines · Serge E. Hallyn

Quoted 22 lines · Sergey Senozhatsky

Quoted 10 lines · Serge E. Hallyn

Quoted 10 lines

re-upping https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html

Oleg Nesterov wrote:

:Because is_global_init() is only true for the main thread of /sbin/init. :
:Just look at oom_unkillable_task(). It tries to not kill init. But, say, :select_bad_process() can happily find a sub-thread of is_global_init() :and still kill it.

Quoted 7 lines

Quoted 3 lines

this is still the case, isn't it? at least in some -stable kernels. is there (or was there) any reason this change has never been committed? (I'm particularly interested in is_global_init()).

... seems like it makes sense. Can you remind us which init you're having to deal with?

systemd

	-ss

Quoted 4 lines

Well it makes sense to me. The question is whether we are protecting the thing running as init, or the 'physical' thread with pid 1. I think it's the former, so let's push on this. Please resend the patch with a proper signed-off-by, and feel free to add

thanks. a bit puzzled, would reported-by Oleg and suggested-by Richard be appropriate? (no objections if Oleg or Richard will submit it).

Quoted 1 line

Acked-by Serge Hallyn <[email protected]>

	-ss