From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vmicros1.altlinux.org (vmicros1.altlinux.org [194.107.17.57]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1FD7F3C454E for ; Thu, 9 Jul 2026 07:59:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.107.17.57 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783583967; cv=none; b=VxirkboAZkzdAGMeLboSZoMORoAE103k88PNAybyhZVQ0Jj5cRdCLK3SHmLNOYF50wHwPh7RFXteB1l5NFWj+tPqxr1+Wi87zGm85OlFrVJOrIuEa7YhAWlMt0p5cTDYaK0a7Si1SP7Ms70u8xNxw+Xj26FFqvM9cpxqZMJbyr0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783583967; c=relaxed/simple; bh=NMTkW4uW6HOhHg0JB1U+2NK8Y2HDlSM/SYAD+m5M6rM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KX+vNEwsgvhbSzGMxIOMlmniYMsKbfiF1j38SctX6y9g7odfwHJ0uNWt1hDE6C0HS+EB5AB2Trm0D4RZbyw2yOZOBvLhxm/7PCQ2XTKm+gyH8iAaV2kBcnr5EYdVu2zf0fltu9VufJUq88Q9L40MtTrMhQFRpvT9G6GeyQwRGXI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strace.io; spf=pass smtp.mailfrom=altlinux.org; arc=none smtp.client-ip=194.107.17.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strace.io Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=altlinux.org Received: from mua.local.altlinux.org (mua.local.altlinux.org [192.168.1.14]) by vmicros1.altlinux.org (Postfix) with ESMTP id A211272C8CC; Thu, 9 Jul 2026 10:59:23 +0300 (MSK) Received: by mua.local.altlinux.org (Postfix, from userid 508) id 6FB577CCB3A; Thu, 9 Jul 2026 10:59:23 +0300 (IDT) Date: Thu, 9 Jul 2026 10:59:23 +0300 From: "Dmitry V. Levin" To: Sven Schnelle Cc: strace development discussions , linux-kernel@vger.kernel.org, Renzo Davoli , Andrew Morton , Oleg Nesterov , Shuah Khan , Alexey Gladkov , Eugene Syromyatnikov , Davide Berardi Subject: Re: [PATCH v2 1/5] ptrace: PTRACE_SET_SYSCALL_INFO syscall skipping support Message-ID: <20260709075923.GA16739@strace.io> References: <20260703105027.539399-1-renzo@cs.unibo.it> <20260703105027.539399-2-renzo@cs.unibo.it> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Jul 09, 2026 at 09:04:34AM +0200, Sven Schnelle wrote: > Renzo Davoli writes: > > > This patch extends PTRACE_SET_SYSCALL_INFO with support for skipping a system > > call triggered via seccomp. > > > > When the tracer retrieves a ptrace_syscall_info structure with > > op == PTRACE_SYSCALL_INFO_SECCOMP, it may choose to skip the system > > call by changing op to PTRACE_SYSCALL_INFO_EXIT and > > populating the exit union fields (rval and is_error) to define > > the return value and error status for the tracee. > > Is it possible to indicate the information whether the syscall should be > skipped via a dedicated return value? Currently, there is no API for that, so everybody has been using -1 for that purpose. > There's currently work going on[1] > to do this for seccomp, and it would be awkward if ptrace introduces > this at the same time. If someday there would be a better API for that, ptrace could be able to use it as well. -- ldv