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From: Oleg Nesterov <oleg@redhat.com>
To: Renzo Davoli <renzo@cs.unibo.it>
Cc: linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Shuah Khan <shuah@kernel.org>, Alexey Gladkov <legion@kernel.org>,
	Eugene Syromyatnikov <evgsyr@gmail.com>,
	Davide Berardi <berardi.dav@gmail.com>,
	strace-devel@lists.strace.io, "Dmitry V . Levin" <ldv@strace.io>
Subject: Re: [PATCH 1/2] ptrace: PTRACE_SET_SYSCALL_INFO syscall skipping support
Date: Sat, 4 Jul 2026 13:17:48 +0200	[thread overview]
Message-ID: <akjr3HZoLOdBOj1a@redhat.com> (raw)
In-Reply-To: <20260704083359.632410-2-renzo@cs.unibo.it>

On 07/04, Renzo Davoli wrote:
>
> -	/* Changing the type of the system call stop is not supported yet. */
> -	if (ptrace_get_syscall_info_op(child) != info.op)
> -		return -EINVAL;
> +	/*
> +	 * Changing the type of the system call stop is not allowed, with the
> +	 * following exception:
> +	 * PTRACE_SYSCALL_INFO_SECCOMP or PTRACE_SYSCALL_INFO_ENTRY can be changed
> +	 * to PTRACE_SYSCALL_INFO_EXIT to skip the system call
> +	 */
> +
> +	if (ptrace_get_syscall_info_op(child) != info.op) {
> +		if (info.op != PTRACE_SYSCALL_INFO_EXIT)
> +			return -EINVAL;
> +		skip_syscall = true;
> +	}

Ah... I forgot that ptrace_get_syscall_info_op() can return _NONE.

We should not allow _NONE -> _EXIT transition.

Oleg.


  reply	other threads:[~2026-07-04 11:18 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-04  8:33 [PATCH 0/2] ptrace_set_syscall_info: add support for seccomp syscall skipping Renzo Davoli
2026-07-04  8:33 ` [PATCH 1/2] ptrace: PTRACE_SET_SYSCALL_INFO syscall skipping support Renzo Davoli
2026-07-04 11:17   ` Oleg Nesterov [this message]
2026-07-04 14:25     ` Renzo Davoli
2026-07-04  8:33 ` [PATCH 2/2] selftests/ptrace: add a test case for PTRACE_SYSCALL_INFO syscall skipping Renzo Davoli

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