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From: Oleg Nesterov <oleg@redhat.com>
To: Andrei Vagin <avagin@gmail.com>
Cc: linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] ptrace: take into account saved_sigmask in PTRACE_{GET,SET}SIGMASK
Date: Tue, 27 Nov 2018 17:23:27 +0100	[thread overview]
Message-ID: <20181127162326.GB13284@redhat.com> (raw)
In-Reply-To: <20181127063758.GA10422@gmail.com>

On 11/26, Andrei Vagin wrote:
>
> > IOW, could you please explain how PTRACE_SETSIGMASK should be used, and why
> > it doesn't do something like
> >
>
> CRIU uses PTRACE_SETSIGMASK when it injects a parasite code into a
> target process. In this case, we have to be sure that when the process
> is resumed by PTRACE_CONT, it will not start handling signals and
> executing signal handlers.

So iiuc CRUI uses PTRACE_SETSIGMASK to block all signals, run the parasite
code, then restore the original sigmask.

Assuming that CRIU also turns ERESTARTNOHAND into syscall-restart (I think
it does ;) everything looks correct...

OK, I think the patch is fine.

Oleg.


      reply	other threads:[~2018-11-27 16:23 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-20  6:06 [PATCH] ptrace: take into account saved_sigmask in PTRACE_{GET,SET}SIGMASK Andrei Vagin
2018-11-22  2:16 ` Andrew Morton
2018-11-29 18:05   ` [PATCH] include: replace tsk to task in linux/sched/signal.h Andrei Vagin
2019-02-02 10:04   ` [PATCH] ptrace: take into account saved_sigmask in PTRACE_{GET,SET}SIGMASK Andrei Vagin
2018-11-22 11:47 ` Oleg Nesterov
2018-11-27  6:38   ` Andrei Vagin
2018-11-27 16:23     ` Oleg Nesterov [this message]

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