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 D76F3E8782C for ; Tue, 3 Feb 2026 13:37:31 +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-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=elgNqx8q9SSGC3qz/N2mFx9V6p9uKgkkJP1/0OOPjBg=; b=tN0igxru0wBW4kJ1YS5wIrF3zz 7SRjh897cmpDlU9INEv85YVxboVcWWmpQpB7GomPL6kxIcWILOb/mIeWnFCKWzlyO3OgRp+/3ba9a uBJOSMV5q/VN2ADwP1zFIVEX84FWO1cNilWeGX8+88xF/GfdRYqjazNi7oNv4P7dm8RVEXFg8h/Ti W1pbTRBxLZYbaQoJtggKCuPpZsa46phiSX5QkMLXw5hRVUT8xKwDQYxfFI970ACBmLuZoJLdrSl/S +LkZkTVhyGaQzyZvxVVzuhmRZYnnSPB9fRAWxXtvoxY0J/p5nOOoiGY7mLf3MLCRVP/DpUFhI28yq 5meSG8eQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnGar-00000006g55-2iU3; Tue, 03 Feb 2026 13:37:25 +0000 Received: from canpmsgout08.his.huawei.com ([113.46.200.223]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnGam-00000006fxi-1hgZ for linux-arm-kernel@lists.infradead.org; Tue, 03 Feb 2026 13:37:24 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=elgNqx8q9SSGC3qz/N2mFx9V6p9uKgkkJP1/0OOPjBg=; b=IlBgGp6FxoUxRLrGCNjE0de/SNhWoHPDnWfU9mC+1kMA6sg2nmY3TE0USpLgWVnI7oYd7av8p zTelKMyrcfNRNutOj9kpTZV4Rrnxt6u52Szbmiy5zOpqtrZ8nhMJkr/OakWqwV5BsOO99ehXRpw Uqo61SHK8A6LXJIbeGguYfI= Received: from mail.maildlp.com (unknown [172.19.162.92]) by canpmsgout08.his.huawei.com (SkyGuard) with ESMTPS id 4f54D90FFxzmV6s; Tue, 3 Feb 2026 21:32:41 +0800 (CST) Received: from dggpemf500011.china.huawei.com (unknown [7.185.36.131]) by mail.maildlp.com (Postfix) with ESMTPS id 8F58240565; Tue, 3 Feb 2026 21:37:15 +0800 (CST) Received: from huawei.com (10.90.53.73) by dggpemf500011.china.huawei.com (7.185.36.131) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 3 Feb 2026 21:37:13 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: Subject: [PATCH v12 07/13] arm64: ptrace: Move rseq_syscall() before audit_syscall_exit() Date: Tue, 3 Feb 2026 21:37:22 +0800 Message-ID: <20260203133728.848283-8-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260203133728.848283-1-ruanjinjie@huawei.com> References: <20260203133728.848283-1-ruanjinjie@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: kwepems200002.china.huawei.com (7.221.188.68) To dggpemf500011.china.huawei.com (7.185.36.131) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260203_053721_780088_DF5319EE X-CRM114-Status: GOOD ( 13.34 ) 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 commit a9f3a74a29af ("entry: Provide generic syscall exit function") introduce generic syscall exit function and call rseq_syscall() before audit_syscall_exit() and arch_syscall_exit_tracehook(). And commit b74406f37737 ("arm: Add syscall detection for restartable sequences") add rseq support for arm32, which also call rseq_syscall() before audit_syscall_exit() and tracehook_report_syscall(). However, commit 409d5db49867c ("arm64: rseq: Implement backend rseq calls and select HAVE_RSEQ") implement arm64 rseq and call rseq_syscall() after audit_syscall_exit() and tracehook_report_syscall(). So compared to the generic entry and arm32 code, arm64 calls rseq_syscall() a bit later. But as commit b74406f37737 ("arm: Add syscall detection for restartable sequences") said, syscalls are not allowed inside restartable sequences, so should call rseq_syscall() at the very beginning of system call exiting path for CONFIG_DEBUG_RSEQ=y kernel. This could help us to detect whether there is a syscall issued inside restartable sequences. To align the order of the calls with generic entry, move rseq_syscall() ahead before audit_syscall_exit(). As for the impact of raising SIGSEGV via rseq_syscall(), it makes no practical difference to signal delivery because signals are processed in arm64_exit_to_user_mode() at the very end. As for the "regs", rseq_syscall() only checks and update instruction_pointer(regs) when CONFIG_DEBUG_RSEQ=y, audit_syscall_exit() only checks the return value (x0 for arm64), so calling rseq_syscall() before or after audit syscall exit makes no difference. trace_sys_exit() only uses syscallno and the return value, so calling rseq_syscall() before or after trace_sys_exit() makes no difference. But ptrace can also modify the "pc" on syscall exit path. So when CONFIG_DEBUG_RSEQ=y, before this patch, rseq could observe the PC modified by ptrace on the syscall exit path; after this patch, rseq no longer sees modifications made by ptrace. Reviewed-by: Kevin Brodsky Signed-off-by: Jinjie Ruan --- arch/arm64/kernel/ptrace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index e3dcadf13e99..50344a2d7b88 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -2455,6 +2455,8 @@ int syscall_trace_enter(struct pt_regs *regs, unsigned long flags) void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) { + rseq_syscall(regs); + audit_syscall_exit(regs); if (flags & _TIF_SYSCALL_TRACEPOINT) @@ -2462,8 +2464,6 @@ void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) if (flags & (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP)) report_syscall_exit(regs); - - rseq_syscall(regs); } /* -- 2.34.1