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From: Oleg Nesterov <oleg@redhat.com>
To: Zhao Gongyi <zhaogongyi@bytedance.com>
Cc: Jinjie Ruan <ruanjinjie@huawei.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	will@kernel.org, mark.rutland@arm.com,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] arm64: ptrace: don't warn on missing siginfo in a group-stop
Date: Mon, 2 Nov 2026 12:31:18 +0100	[thread overview]
Message-ID: <auh0hj3NRzExmgYs@redhat.com> (raw)
In-Reply-To: <8028d335-c304-49de-81fa-07fd446cf9d0@bytedance.com>

On 11/02, Zhao Gongyi wrote:
>
> Hi Jinjie,
>
>
> On 11/2/26 3:54 PM, Jinjie Ruan wrote:
> >
> > I think maybe we can refer to ptrace_get_syscall_info_op()?
> >
>
> Thanks for the suggestion.
>
> I checked ptrace_get_syscall_info_op(). It is currently static to
> kernel/ptrace.c and identifies a syscall stop only when
> last_siginfo->si_code is SIGTRAP | 0x80.
>
> The arm64 path here also needs to handle a syscall-exit-stop when the
> tracer has not enabled PTRACE_O_TRACESYSGOOD. In that case, the tested

Yes, PTRACE_GET_SYSCALL_INFO/etc depends on PTRACE_O_TRACESYSGOOD
by design, this is even documented in man 2 ptrace.

> For this patch, I think
> the local check of last_siginfo, with bit 0x80 masked and ptrace_message
> checked for PTRACE_EVENTMSG_SYSCALL_EXIT, is the smaller and safer change.

Agreed.

Oleg.


      reply	other threads:[~2026-11-02 11:31 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-23 11:07 Zhao Gongyi
2026-10-23 13:24 ` Oleg Nesterov
2026-10-24 14:50   ` Zhao Gongyi
2026-10-24 15:09     ` Oleg Nesterov
2026-10-26 18:32 ` Catalin Marinas
2026-11-02  7:42   ` Jinjie Ruan
2026-11-02  7:54   ` Jinjie Ruan
2026-11-02  8:45     ` Zhao Gongyi
2026-11-02 11:31       ` Oleg Nesterov [this message]

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