From: Jinjie Ruan <ruanjinjie@huawei.com>
To: Linus Walleij <linusw@kernel.org>
Cc: <catalin.marinas@arm.com>, <will@kernel.org>, <kees@kernel.org>,
<oleg@redhat.com>, <luto@amacapital.net>, <wad@chromium.org>,
<thuth@redhat.com>, <peterz@infradead.org>,
<mark.rutland@arm.com>, <ada.coupriediaz@arm.com>,
<kevin.brodsky@arm.com>, <yeoreum.yun@arm.com>,
<anshuman.khandual@arm.com>, <james.morse@arm.com>,
<tglx@kernel.org>, <broonie@kernel.org>, <pengcan@kylinos.cn>,
<ryan.roberts@arm.com>, <liqiang01@kylinos.cn>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: Re: [PATCH v17 15/15] arm64: vdso: Expose sigreturn address on vdso to the kernel
Date: Tue, 21 Jul 2026 17:27:04 +0800 [thread overview]
Message-ID: <4b6d760a-8270-443b-878f-37d46d9bed47@huawei.com> (raw)
In-Reply-To: <CAD++jL=Ou_HF5VchexnjUf9qwzrz0xgY+NhA5gZhOwiwdxUi-g@mail.gmail.com>
On 7/21/2026 4:55 PM, Linus Walleij wrote:
> On Tue, Jul 21, 2026 at 10:19 AM Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>
>> Syscall User Dispatch (SUD) must not intercept the signal trampoline
>> code, otherwise returning from a signal with a locked selector may
>> cause infinite recursion into the signal handler.
>>
>> Provide an arm64 implementation of arch_syscall_is_vdso_sigreturn()
>> to exclude these sigreturn syscalls from dispatch.
>>
>> For native 64-bit tasks, check whether the current PC matches the 'svc #0'
>> instruction inside the vDSO sigreturn trampoline (defined in
>> arch/arm64/kernel/vdso/sigreturn.S as below).
>>
>> SYM_CODE_START(__kernel_rt_sigreturn)
>> mov x8, #__NR_rt_sigreturn
>> svc #0
>> SYM_CODE_END(__kernel_rt_sigreturn)
>>
>> For COMPAT tasks, verify that the instruction falls within the dedicated
>> 'sigpage' range, since compat signal handlers use this architecture-
>> specific page (not the vDSO) for their return trampoline. This prevents
>> SUD from incorrectly dispatching syscalls issued during signal return.
>>
>> Suggested-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
>> Suggested-by: Kevin Brodsky <kevin.brodsky@arm.com>
>> Suggested-by: kemal <kmal@cock.li>
>> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
>
> I'm a bit scared about SUD.
>
> Certainly we can merge patches 1-14 first and iron out
> any trouble related to that and split this off so a separate
> series to be applied lated?
Yes, Mark's idea is the same. We can place the SUD patch here separately
and wait for thorough testing and review.
Link:
https://lore.kernel.org/all/akZgV0Y4YAmB43_g@J2N7QTR9R3.cambridge.arm.com/
>
> Yours,
> Linus Walleij
next prev parent reply other threads:[~2026-07-21 9:27 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-21 8:18 [PATCH v17 00/15] arm64: entry: Convert to Generic Entry Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 01/15] arm64: ptrace: Skip syscall exit reporting for PTRACE_SYSEMU_SINGLESTEP Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 02/15] arm64: ptrace: Rework audit_syscall_entry() Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 03/15] arm64: ptrace: Open-code seccomp check in syscall_trace_enter() Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 04/15] arm64: ptrace: Rename and clean up syscall_trace_enter() Jinjie Ruan
2026-07-21 8:39 ` Linus Walleij
2026-07-21 8:18 ` [PATCH v17 05/15] arm64: ptrace: Protect rseq_syscall() from tracer PC modifications Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 06/15] arm64: syscall: Rework the syscall exit path in el0_svc_common() Jinjie Ruan
2026-07-21 8:43 ` Linus Walleij
2026-07-21 8:45 ` Linus Walleij
2026-07-21 8:18 ` [PATCH v17 07/15] arm64: ptrace: Pass thread flags to trace enter/exit Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 08/15] arm64: ptrace: Extract arm64_syscall_exit_to_user_mode_work() helper Jinjie Ruan
2026-07-21 8:45 ` Linus Walleij
2026-07-21 8:18 ` [PATCH v17 09/15] arm64: ptrace: Align syscall exit work semantics with generic entry Jinjie Ruan
2026-07-21 8:46 ` Linus Walleij
2026-07-21 8:18 ` [PATCH v17 10/15] arm64: syscall: Use exit-specific flags check in el0_svc_common() Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 11/15] arm64: syscall: Simplify el0_svc_common() syscall exit path Jinjie Ruan
2026-07-21 8:51 ` Linus Walleij
2026-07-21 9:30 ` Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 12/15] arm64: ptrace: Make return type of arm64_syscall_trace_enter() bool Jinjie Ruan
2026-07-21 8:52 ` Linus Walleij
2026-07-21 8:18 ` [PATCH v17 13/15] arm64: entry: Convert to generic entry Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 14/15] arm64: Inline el0_svc_common() Jinjie Ruan
2026-07-21 8:18 ` [PATCH v17 15/15] arm64: vdso: Expose sigreturn address on vdso to the kernel Jinjie Ruan
2026-07-21 8:51 ` Thomas Weißschuh
2026-07-21 9:23 ` Jinjie Ruan
2026-07-21 9:55 ` Thomas Weißschuh
2026-07-21 8:55 ` Linus Walleij
2026-07-21 9:27 ` Jinjie Ruan [this message]
2026-07-22 18:18 ` Mark Rutland
2026-07-23 1:54 ` Jinjie Ruan
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