From: Andrew Morton <akpm@linux-foundation.org>
To: Andrei Vagin <avagin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
linux-kernel@vger.kernel.org,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH] ptrace: take into account saved_sigmask in PTRACE_{GET,SET}SIGMASK
Date: Wed, 21 Nov 2018 18:16:50 -0800 [thread overview]
Message-ID: <20181121181650.8d2d6abcf83b9defb7195cd3@linux-foundation.org> (raw)
In-Reply-To: <20181120060616.6043-1-avagin@gmail.com>
On Mon, 19 Nov 2018 22:06:16 -0800 Andrei Vagin <avagin@gmail.com> wrote:
> There are a few system calls (pselect, ppoll, etc) which replace a task
> sigmask while they are running in a kernel-space
>
> When a task calls one of these syscalls, the kernel saves a current
> sigmask in task->saved_sigmask and sets a syscall sigmask.
>
> On syscall-exit-stop, ptrace traps a task before restoring the
> saved_sigmask, so PTRACE_GETSIGMASK returns the syscall sigmask and
> PTRACE_SETSIGMASK does nothing, because its sigmask is replaced by
> saved_sigmask, when the task returns to user-space.
>
> This patch fixes this problem. PTRACE_GET_SIGMASK returns saved_sigmask
> is it's set. PTRACE_SETSIGMASK drops the TIF_RESTORE_SIGMASK flag.
Looks good to me, but what would I know. I'll await input from Eric
and/or Oleg (please).
> --- a/include/linux/sched/signal.h
> +++ b/include/linux/sched/signal.h
> @@ -417,10 +417,20 @@ static inline void set_restore_sigmask(void)
> set_thread_flag(TIF_RESTORE_SIGMASK);
> WARN_ON(!test_thread_flag(TIF_SIGPENDING));
> }
> +
> +static inline void clear_tsk_restore_sigmask(struct task_struct *tsk)
> +{
> + clear_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK);
> +}
How irritating is it that this file uses "task" 85 times and "tsk" 19
times? What did that gain us? This patch worsens things.
Oh well.
next prev parent reply other threads:[~2018-11-22 2:16 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 [this message]
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
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