From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D5622283FE2; Tue, 18 Nov 2025 17:12:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763485934; cv=none; b=ZkbxGBWoN1CR20ZhXm9q80sLGq+OsBmmj8SIJLJ663Ad4YWx5MpBVAL+lwNcH2MxiWJL742Ujs6lRxpn0aOtA36XBCL4JwPboDPM3DSCn+fBA5flBAwnJZK2lW1Cp26WNdvIA3FRDStl2IUnoL/13RTii9FResgkfMNAM43pIj4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763485934; c=relaxed/simple; bh=rVb/hqAEDh/VX1MxWqR988V+RJ3+PUPsOJQP3K5sjBU=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=czuM8ro7ThPo78SbLkS6gvuS/U3ml/xZK7YO0U+D8R4K3IIR3GXEUx45IfekgniZD+INh0qd/G/uybcqZg+jKhNGwukIzYBjtUCethqd4epP5RQA0j5FyhZx72ZUg5QP1R0yCM2BiriXzEPC73HNQt5M8ntn3fSACdxSAV2ydQo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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; > } >