From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 503011FC8 for ; Thu, 9 Jul 2026 06:07:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783577277; cv=none; b=n/EKx9G/2AIRgUUpAAVNRYXC2UYUpViS2UHIuWLAxi00mM/o0B+cxVHTHdmHovTcgaxMp3xVeRGdIKlrhDi9WPM5Afu3XD34NrrYOirq2xf5cyheGAbq4ueO7m3OOl3nnSO8HsKS8nGhPsX6rM3gjYEPIIrnvvmCRFvOip51beA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783577277; c=relaxed/simple; bh=k+FdUJqzcMe2LW5ypg/WPW/aaoo8yOzSHX6AxUC9tCk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ohce8AM+PJIDmAJ5gwaSlqPZSGFefnP0ReOjAJTwoYh5UyV3NKbhlyp0oxm+uo7RABeBk+3+s9l92hlMHYpw7ofgtJ7+bHIeo9ooZRUmHWQh/SmBqF1Pz5sNxq+A+FupJmuQc2NRgElIM2hBQsWFIODuNKqqdwnXaMF+LeFL5M4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=WYfcEQpt; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WYfcEQpt" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783577275; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=4ubCxCqjAOHGNjMvgAyxZ6KB8EtdF+QJ33SHQWbnHGw=; b=WYfcEQpt0gXlpiWmFUkWSncR7MJd2jHyIwyS0tiKd0xa8rbZJxYiupNbyiM+WOAJxjOLoy RPAsuzfrnWg5tYmqmikLZVi6YxS+PEJbvVAeBTGgQ5Qke5G5VAo4ungTfqg4FIbIxK6Moo 7ocr7SBC79nM64SRfFDpQJIOjIwPrsQ= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-75-zVMwLiWMPSyRe6k0VMbbfA-1; Thu, 09 Jul 2026 02:07:51 -0400 X-MC-Unique: zVMwLiWMPSyRe6k0VMbbfA-1 X-Mimecast-MFC-AGG-ID: zVMwLiWMPSyRe6k0VMbbfA_1783577270 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3EA5E195606D; Thu, 9 Jul 2026 06:07:49 +0000 (UTC) Received: from fedora (unknown [10.44.33.83]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id BD62D3652A; Thu, 9 Jul 2026 06:07:45 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 9 Jul 2026 08:07:48 +0200 (CEST) Date: Thu, 9 Jul 2026 08:07:44 +0200 From: Oleg Nesterov To: "Dmitry V. Levin" Cc: Renzo Davoli , linux-kernel@vger.kernel.org, Andrew Morton , Shuah Khan , Alexey Gladkov , Eugene Syromyatnikov , Davide Berardi , strace-devel@lists.strace.io Subject: Re: [PATCH v4 1/2] ptrace: add PTRACE_SET_SYSCALL_INFO syscall skipping support Message-ID: References: <20260708090655.38432-1-renzo@cs.unibo.it> <20260708090655.38432-2-renzo@cs.unibo.it> <20260708153250.GA32399@strace.io> <20260708220923.GA4523@strace.io> 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: <20260708220923.GA4523@strace.io> X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 On 07/09, Dmitry V. Levin wrote: > > System call suppression via PTRACE_SYSCALL_INFO_ENTRY is currently not > implemented. On some architectures (e.g. MIPS), when a system call is > skipped by setting the syscall number to -1 at the entry stop, the > architecture entry path unconditionally overwrites the return value > register with -ENOSYS, clobbering any custom return value set by the > tracer at the entry stop. Thanks! LGTM. Oleg.