Re: [PATCH 1/1] signals: introduce send_sigkill() helper

From: KAMEZAWA Hiroyuki
Date: Thu Jun 10 2010 - 20:45:22 EST


On Thu, 10 Jun 2010 03:00:23 +0200
Oleg Nesterov <oleg@xxxxxxxxxx> wrote:

> Cleanup, no functional changes.
>
> There are a lot of buggy SIGKILL users in kernel. For example, almost
> every force_sig(SIGKILL) is wrong. force_sig() is not safe, it assumes
> that the task has the valid ->sighand, and in general it should be used
> only for synchronous signals. send_sig(SIGKILL, p, 1) or
> send_xxx(SEND_SIG_FORCED/SEND_SIG_PRIV) is not right too but this is not
> immediately obvious.
>
> The only way to correctly send SIGKILL is send_sig_info(SEND_SIG_NOINFO)
> but we do not want to use this directly, because we can optimize this
> case later. For example, zap_pid_ns_processes() allocates sigqueue for
> each process in namespace, this is unneeded.
>
> Introduce the trivial send_sigkill() helper on top of send_sig_info()
> and change zap_pid_ns_processes() as an example.
>
> Note: we need more cleanups here, this is only the first change.
>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

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