From mboxrd@z Thu Jan  1 00:00:00 1970
From: Oleg Nesterov <oleg@redhat.com>
Subject: Re: [RFC PATCH RESEND v3 3/3] ptrace: add PTRACE_EVENT_SECCOMP
 support to PTRACE_GET_SYSCALL_INFO
Date: Wed, 28 Nov 2018 14:13:48 +0100
Message-ID: <20181128131347.GB30395@redhat.com>
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To: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: Elvira Khabirova <lineprinter@altlinux.org>, Eugene Syromyatnikov <esyr@redhat.com>, Steven Rostedt <rostedt@goodmis.org>, Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, strace-devel@lists.strace.io
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On 11/28, Dmitry V. Levin wrote:
>
> What about PTRACE_GETSIGINFO?  Can it also be done lockless because
> ptrace_check_attach() has already called ptrace_freeze_traced()?

Yes, only PTRACE_INTERRUPT needs lock_task_sighand() and it can actually
fail because the tracee is not necessarily stopped.

Oleg.