From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751795AbeBWJZH (ORCPT ); Fri, 23 Feb 2018 04:25:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:44784 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751481AbeBWJZF (ORCPT ); Fri, 23 Feb 2018 04:25:05 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B68152178B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=mhiramat@kernel.org From: Masami Hiramatsu To: Russell King Cc: Wang Nan , Will Deacon , Jon Medhurst , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org Subject: [PATCH] [BUGFIX] arm: kprobes: Fix to use get_kprobe_ctlblk after irq-disabed Date: Fri, 23 Feb 2018 18:24:40 +0900 Message-Id: <151937788067.22527.14819753928851623471.stgit@devbox> X-Mailer: git-send-email 2.13.6 User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since get_kprobe_ctlblk() uses smp_processor_id() to access per-cpu variable, it hits smp_processor_id sanity check as below. [ 7.006928] BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1 [ 7.007859] caller is debug_smp_processor_id+0x20/0x24 [ 7.008438] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0-rc1-00192-g4eb17253e4b5 #1 [ 7.008890] Hardware name: Generic DT based system [ 7.009917] [] (unwind_backtrace) from [] (show_stack+0x20/0x24) [ 7.010473] [] (show_stack) from [] (dump_stack+0x84/0x98) [ 7.010990] [] (dump_stack) from [] (check_preemption_disabled+0x138/0x13c) [ 7.011592] [] (check_preemption_disabled) from [] (debug_smp_processor_id+0x20/0x24) [ 7.012214] [] (debug_smp_processor_id) from [] (optimized_callback+0x2c/0xe4) [ 7.013077] [] (optimized_callback) from [] (0xbf0021b0) To fix this issue, call get_kprobe_ctlblk() right after irq-disabled since that disables preemption. Fixes: 0dc016dbd820 ("ARM: kprobes: enable OPTPROBES for ARM 32") Signed-off-by: Masami Hiramatsu --- arch/arm/probes/kprobes/opt-arm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c index bcdecc25461b..ddc5a82eb10d 100644 --- a/arch/arm/probes/kprobes/opt-arm.c +++ b/arch/arm/probes/kprobes/opt-arm.c @@ -165,13 +165,14 @@ optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs) { unsigned long flags; struct kprobe *p = &op->kp; - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + struct kprobe_ctlblk *kcb; /* Save skipped registers */ regs->ARM_pc = (unsigned long)op->kp.addr; regs->ARM_ORIG_r0 = ~0UL; local_irq_save(flags); + kcb = get_kprobe_ctlblk(); if (kprobe_running()) { kprobes_inc_nmissed_count(&op->kp);