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Message-ID: <20190319223252.GA19424@altlinux.org>
Date: Wed, 20 Mar 2019 01:32:53 +0300
From: "Dmitry V. Levin" <ldv@...linux.org>
To: Andrei Vagin <avagin@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Oleg Nesterov <oleg@...hat.com>, linux-kernel@...r.kernel.org,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Stephen Rothwell <sfr@...b.auug.org.au>
Subject: Re: [RESEND PATCH] ptrace: take into account saved_sigmask in
PTRACE_{GET,SET}SIGMASK
On Tue, Mar 19, 2019 at 12:19:57PM -0700, Andrei Vagin 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.
If it's not too late, could somebody tweak the commit message so that
PTRACE_GET_SIGMASK becomes PTRACE_GETSIGMASK and "is it's set" is changed
to "if it's set", please?
--
ldv
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