From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 789DDCEE341 for ; Tue, 18 Nov 2025 17:12:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=c7eJ5hJBlt7c4B4di5d+Js72tP1QdBc/i0mzeTtCatQ=; b=UcWiIgbuPFAvvMauf29sUWyMUf h8j5ew5l8l06Gt64tZwjY//cpTGSqV9tRYuChyUmcQJ6r/iksDEGjAzBoO3fQDVuZNkcKRr1T5pFZ SVih2a5VyLhIj78czcIq83UQlYmFsf/2yAbHRODLSWUmsHe6pKunXCdDbKnPw38RA3dodhouCG1bb 5NcPmtN/caCxnyPX+1kRoEmGUJErcH6X+Nhg6TczsE5Ol4sZfVCRsPdJZob0YjojCOjyoMS4/6JsX YYKA4p5ckq8Bo0ZsrB46uGZ2sdSRSz+FSzitGXWZ19/9Jn/TbxubvdHq6X/dRR6Vkzyofpex6wHOV +6pIe2bw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLPFY-00000000pMh-0nMB; Tue, 18 Nov 2025 17:12:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLPFU-00000000pLn-3L06 for linux-arm-kernel@lists.infradead.org; Tue, 18 Nov 2025 17:12:14 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 921DB1596; Tue, 18 Nov 2025 09:12:04 -0800 (PST) Received: from [10.57.39.196] (unknown [10.57.39.196]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 90A1D3F66E; Tue, 18 Nov 2025 09:12:07 -0800 (PST) Message-ID: Date: Tue, 18 Nov 2025 18:12:05 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 05/11] arm64/ptrace: Handle ptrace_report_syscall_entry() error To: Jinjie Ruan , catalin.marinas@arm.com, will@kernel.org, oleg@redhat.com, tglx@linutronix.de, peterz@infradead.org, luto@kernel.org, shuah@kernel.org, kees@kernel.org, wad@chromium.org, akpm@linux-foundation.org, ldv@strace.io, macro@orcam.me.uk, deller@gmx.de, mark.rutland@arm.com, song@kernel.org, mbenes@suse.cz, ryan.roberts@arm.com, ada.coupriediaz@arm.com, anshuman.khandual@arm.com, broonie@kernel.org, pengcan@kylinos.cn, dvyukov@google.com, kmal@cock.li, lihongbo22@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20251117133048.53182-1-ruanjinjie@huawei.com> <20251117133048.53182-6-ruanjinjie@huawei.com> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: <20251117133048.53182-6-ruanjinjie@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251118_091212_952403_E666E952 X-CRM114-Status: GOOD ( 21.38 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 17/11/2025 14:30, Jinjie Ruan wrote: > The generic entry handle error of ptrace_report_syscall_entry(), but > arm64 not. This suggests that arm64 ignores the error completely, which isn't the case: no syscall will be performed, but tracing will still occur as normal. What this patch seems to be doing is to abort the _enter sequence if ptrace_report_syscall_entry() errors out. The commit title and message should be reworded accordingly. > As the comment said, the calling arch code should abort the system Which comment? > call and must prevent normal entry so no system call is > made if ptrace_report_syscall_entry() return nonzero. This is already the case since we're calling forget_syscall(). > In preparation for moving arm64 over to the generic entry code, > return early if ptrace_report_syscall_entry() encounters an error. > > Signed-off-by: Jinjie Ruan > --- > arch/arm64/kernel/ptrace.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c > index 95984bbf53db..707951ad5d24 100644 > --- a/arch/arm64/kernel/ptrace.c > +++ b/arch/arm64/kernel/ptrace.c > @@ -2317,10 +2317,10 @@ enum ptrace_syscall_dir { > PTRACE_SYSCALL_EXIT, > }; > > -static void report_syscall_enter(struct pt_regs *regs) > +static int report_syscall_enter(struct pt_regs *regs) > { > - int regno; > unsigned long saved_reg; > + int regno, ret; > > /* > * We have some ABI weirdness here in the way that we handle syscall > @@ -2342,9 +2342,13 @@ static void report_syscall_enter(struct pt_regs *regs) > saved_reg = regs->regs[regno]; > regs->regs[regno] = PTRACE_SYSCALL_ENTER; > > - if (ptrace_report_syscall_entry(regs)) > + ret = ptrace_report_syscall_entry(regs); > + if (ret) > forget_syscall(regs); The generic syscall_trace_enter() doesn't do this (i.e. setting regs->syscallno to NO_SYSCALL). Is that an oversight or do we just not need it? In principle this does have a visible effect (e.g. via REGSET_SYSTEM_CALL). - Kevin > + > regs->regs[regno] = saved_reg; > + > + return ret; > } > > static void report_syscall_exit(struct pt_regs *regs) > @@ -2374,9 +2378,11 @@ static void report_syscall_exit(struct pt_regs *regs) > > int syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long flags) > { > + int ret; > + > if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) { > - report_syscall_enter(regs); > - if (flags & _TIF_SYSCALL_EMU) > + ret = report_syscall_enter(regs); > + if (ret || (flags & _TIF_SYSCALL_EMU)) > return NO_SYSCALL; > } >