From patchwork Tue Apr 11 16:29:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13207863 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 83EAEC77B70 for ; Tue, 11 Apr 2023 16:31:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id: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=olT/ojysUg3HiRGBAXqf4QXMnRSjcYBx5Lga6MT+Jto=; b=L4zseC0/mCecj/ lobObkD2ZC6NRfUE9vz+zkTFGx07iAHHkc9NGzU56yzBPYqUfOOMPjsxSwmz3gBlwYGS6a/efeqa5 gI5QR5Wiu2785sN7GYbDSrO0+S2/AMrl6Pw3+e4CHQQO4A1gHcKWoxK5FtNd5y1L1OFs+nm+6o2NH czzsUGbl6axMjiPBf94Mfl+dGjxnxBgL3/eFH7m9d//v5WERFXWvhgrmfke1VUC/NvGG3VBARTR/5 Ebm6a3n8y/06ncBeLNYHEzVhDZYOSfPskAs315+3Alev0fqLR1c0SV+HLRbJREwt0N8j+wb6wcXPa igk3rtVpsxySRysdiNEQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pmGsg-000YrW-2v; Tue, 11 Apr 2023 16:30:06 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pmGsZ-000YpF-1j for linux-arm-kernel@lists.infradead.org; Tue, 11 Apr 2023 16:30:01 +0000 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 B4CF1FEC; Tue, 11 Apr 2023 09:30:41 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 559443F73F; Tue, 11 Apr 2023 09:29:56 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: broonie@kernel.org, catalin.marinas@arm.com, kaleshsingh@google.com, madvenka@linux.microsoft.com, mark.rutland@arm.com, will@kernel.org Subject: [PATCH v2 1/3] arm64: stacktrace: recover return address for first entry Date: Tue, 11 Apr 2023 17:29:41 +0100 Message-Id: <20230411162943.203199-2-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230411162943.203199-1-mark.rutland@arm.com> References: <20230411162943.203199-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230411_092959_666179_59FE58D1 X-CRM114-Status: GOOD ( 14.40 ) 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 The function which calls the top-level backtracing function may have been instrumented with ftrace and/or kprobes, and hence the first return address may have been rewritten. Factor out the existing fgraph / kretprobes address recovery, and use this for the first address. As the comment for the fgraph case isn't all that helpful, I've also dropped that. Signed-off-by: Mark Rutland Reviewed-by: Kalesh Singh Cc: Catalin Marinas Cc: Madhavan T. Venkataraman Cc: Mark Brown Cc: Will Deacon --- arch/arm64/kernel/stacktrace.c | 53 +++++++++++++++++++--------------- 1 file changed, 30 insertions(+), 23 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 83154303e682c..dd03feba80481 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -69,6 +69,32 @@ static __always_inline void unwind_init_from_task(struct unwind_state *state, state->pc = thread_saved_pc(task); } +static __always_inline int +unwind_recover_return_address(struct unwind_state *state) +{ +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + if (state->task->ret_stack && + (state->pc == (unsigned long)return_to_handler)) { + unsigned long orig_pc; + orig_pc = ftrace_graph_ret_addr(state->task, NULL, state->pc, + (void *)state->fp); + if (WARN_ON_ONCE(state->pc == orig_pc)) + return -EINVAL; + state->pc = orig_pc; + } +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_KRETPROBES + if (is_kretprobe_trampoline(state->pc)) { + state->pc = kretprobe_find_ret_addr(state->task, + (void *)state->fp, + &state->kr_cur); + } +#endif /* CONFIG_KRETPROBES */ + + return 0; +} + /* * Unwind from one frame record (A) to the next frame record (B). * @@ -92,35 +118,16 @@ static int notrace unwind_next(struct unwind_state *state) state->pc = ptrauth_strip_insn_pac(state->pc); -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - if (tsk->ret_stack && - (state->pc == (unsigned long)return_to_handler)) { - unsigned long orig_pc; - /* - * This is a case where function graph tracer has - * modified a return address (LR) in a stack frame - * to hook a function return. - * So replace it to an original value. - */ - orig_pc = ftrace_graph_ret_addr(tsk, NULL, state->pc, - (void *)state->fp); - if (WARN_ON_ONCE(state->pc == orig_pc)) - return -EINVAL; - state->pc = orig_pc; - } -#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ -#ifdef CONFIG_KRETPROBES - if (is_kretprobe_trampoline(state->pc)) - state->pc = kretprobe_find_ret_addr(tsk, (void *)state->fp, &state->kr_cur); -#endif - - return 0; + return unwind_recover_return_address(state); } NOKPROBE_SYMBOL(unwind_next); static void notrace unwind(struct unwind_state *state, stack_trace_consume_fn consume_entry, void *cookie) { + if (unwind_recover_return_address(state)) + return; + while (1) { int ret;