From nobody Thu Sep 18 23:13:21 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8DB64C43217 for ; Thu, 1 Dec 2022 14:39:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231854AbiLAOjM (ORCPT ); Thu, 1 Dec 2022 09:39:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231851AbiLAOjK (ORCPT ); Thu, 1 Dec 2022 09:39:10 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33406A8943 for ; Thu, 1 Dec 2022 06:39:09 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D91BBB81F54 for ; Thu, 1 Dec 2022 14:39:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81049C43151; Thu, 1 Dec 2022 14:39:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669905546; bh=DsgCcdAHypRC6WE6LOjXeWdrtqezoJ6nKI9UU3nEiy4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q2mmCU40nv1ThpqRBWHEKBqrN9tkNf47L+j+hfULS3VDH8XiT6/m90vxYw5cFCE1w UlncFgw+C/1elEWCXX7rDIPBONFaWgK3Fq/p8BcEobwxAGeS0+TtqkqxZKnzKCFXnZ zen4jEelxst3aZzPz14n+KtLJ+CNkaLXnj52RecGhX7qfhRHgClH0QIrHoVxHUXULk 9psIqagbN+VFQg0n8quC7CAdve+sN+fkakAgxiuC22e5Tu0yoTOCg0JfrULgYN1t7l R/8PahDQ5wTyHkAdSSbM/ftodBYiuJXzpgxtSA1gtX5ZgKP0Jl299whyi2kVzlVpA0 I57Q2iofRPa0A== From: "Masami Hiramatsu (Google)" To: Catalin Marinas , Will Deacon Cc: Mark Rutland , Mark Brown , Kalesh Singh , Masami Hiramatsu , Marc Zyngier , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sandeepa Prabhu Subject: [PATCH 1/3] arm64: Prohibit probing on arch_stack_walk() Date: Thu, 1 Dec 2022 23:39:02 +0900 Message-Id: <166990554210.253128.7378208454827328942.stgit@devnote3> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog In-Reply-To: <166990553243.253128.13594802750635478633.stgit@devnote3> References: <166990553243.253128.13594802750635478633.stgit@devnote3> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masami Hiramatsu (Google) Make arch_stack_walk() as NOKPROBE_SYMBOL and make other inline functions called from arch_stack_walk() as nokprobe_inline so that user does not put probe on it, because this function can be used from return_address() which is already NOKPROBE_SYMBOL. Without this, if the kernel built with CONFIG_LOCKDEP=3Dy, just probing arch_stack_walk() via /kprobe_events will crash the kernel on arm64. # echo p arch_stack_walk >> ${TRACEFS}/kprobe_events # echo 1 > ${TRACEFS}/events/kprobes/enable kprobes: Failed to recover from reentered kprobes. kprobes: Dump kprobe: .symbol_name =3D arch_stack_walk, .offset =3D 0, .addr =3D arch_stack_wal= k+0x0/0x1c0 ------------[ cut here ]------------ kernel BUG at arch/arm64/kernel/probes/kprobes.c:241! kprobes: Failed to recover from reentered kprobes. kprobes: Dump kprobe: .symbol_name =3D arch_stack_walk, .offset =3D 0, .addr =3D arch_stack_wal= k+0x0/0x1c0 ------------[ cut here ]------------ kernel BUG at arch/arm64/kernel/probes/kprobes.c:241! PREEMPT SMP Modules linked in: CPU: 0 PID: 17 Comm: migration/0 Tainted: G N 6.1.0-rc5+ = #6 Hardware name: linux,dummy-virt (DT) Stopper: 0x0 <- 0x0 pstate: 600003c5 (nZCv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=3D--) pc : kprobe_breakpoint_handler+0x178/0x17c lr : kprobe_breakpoint_handler+0x178/0x17c sp : ffff8000080d3090 x29: ffff8000080d3090 x28: ffff0df5845798c0 x27: ffffc4f59057a774 x26: ffff0df5ffbba770 x25: ffff0df58f420f18 x24: ffff49006f641000 x23: ffffc4f590579768 x22: ffff0df58f420f18 x21: ffff8000080d31c0 x20: ffffc4f590579768 x19: ffffc4f590579770 x18: 0000000000000006 x17: 5f6b636174735f68 x16: 637261203d207264 x15: 64612e202c30203d x14: 2074657366666f2e x13: 30633178302f3078 x12: 302b6b6c61775f6b x11: 636174735f686372 x10: ffffc4f590dc5bd8 x9 : ffffc4f58eb31958 x8 : 00000000ffffefff x7 : ffffc4f590dc5bd8 x6 : 80000000fffff000 x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : ffff0df5845798c0 x0 : 0000000000000064 Call trace: kprobes: Failed to recover from reentered kprobes. kprobes: Dump kprobe: .symbol_name =3D arch_stack_walk, .offset =3D 0, .addr =3D arch_stack_wal= k+0x0/0x1c0 ------------[ cut here ]------------ kernel BUG at arch/arm64/kernel/probes/kprobes.c:241! Fixes: 39ef362d2d45 ("arm64: Make return_address() use arch_stack_walk()") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) --- arch/arm64/kernel/stacktrace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 634279b3b03d..b0e913f944b4 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -23,7 +23,7 @@ * * The regs must be on a stack currently owned by the calling task. */ -static inline void unwind_init_from_regs(struct unwind_state *state, +static nokprobe_inline void unwind_init_from_regs(struct unwind_state *sta= te, struct pt_regs *regs) { unwind_init_common(state, current); @@ -40,7 +40,7 @@ static inline void unwind_init_from_regs(struct unwind_st= ate *state, * * The function which invokes this must be noinline. */ -static __always_inline void unwind_init_from_caller(struct unwind_state *s= tate) +static nokprobe_inline void unwind_init_from_caller(struct unwind_state *s= tate) { unwind_init_common(state, current); =20 @@ -58,7 +58,7 @@ static __always_inline void unwind_init_from_caller(struc= t unwind_state *state) * duration of the unwind, or the unwind will be bogus. It is never valid = to * call this for the current task. */ -static inline void unwind_init_from_task(struct unwind_state *state, +static nokprobe_inline void unwind_init_from_task(struct unwind_state *sta= te, struct task_struct *task) { unwind_init_common(state, task); @@ -218,3 +218,4 @@ noinline notrace void arch_stack_walk(stack_trace_consu= me_fn consume_entry, =20 unwind(&state, consume_entry, cookie); } +NOKPROBE_SYMBOL(arch_stack_walk);