Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757241AbcK2Nqv (ORCPT ); Tue, 29 Nov 2016 08:46:51 -0500 Received: from mail-lf0-f67.google.com ([209.85.215.67]:36322 "EHLO mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756979AbcK2Npk (ORCPT ); Tue, 29 Nov 2016 08:45:40 -0500 From: Alexander Kochetkov To: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Cc: Thomas Gleixner , Heiko Stuebner , Mark Rutland , Rob Herring , Russell King , Caesar Wang , Huang Tao , Daniel Lezcano , Alexander Kochetkov Subject: [PATCH v3 13/13] clocksource/drivers/rockchip_timer: Prevent ftrace recursion Date: Tue, 29 Nov 2016 16:45:18 +0300 Message-Id: <1480427118-5126-14-git-send-email-al.kochet@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1480427118-5126-1-git-send-email-al.kochet@gmail.com> References: <1480343486-25539-1-git-send-email-al.kochet@gmail.com> <1480427118-5126-1-git-send-email-al.kochet@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1717 Lines: 51 Currently rockchip_timer can be used as a scheduler clock. We properly marked rk_timer_sched_clock_read() as notrace but we then call another function rk_timer_counter_read() that _wasn't_ notrace. Having a traceable function in the sched_clock() path leads to a recursion within ftrace and a kernel crash. Fix this by adding an extra notrace function to keep other users of rk_timer_counter_read() traceable. Signed-off-by: Alexander Kochetkov --- drivers/clocksource/rockchip_timer.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/clocksource/rockchip_timer.c b/drivers/clocksource/rockchip_timer.c index 1af80a0..a127822 100644 --- a/drivers/clocksource/rockchip_timer.c +++ b/drivers/clocksource/rockchip_timer.c @@ -87,7 +87,7 @@ static void rk_timer_update_counter(u64 cycles, struct rk_timer *timer) writel_relaxed(upper, timer->base + TIMER_LOAD_COUNT1); } -static u64 rk_timer_counter_read(struct rk_timer *timer) +static u64 notrace _rk_timer_counter_read(struct rk_timer *timer) { u64 counter; u32 lower; @@ -106,6 +106,11 @@ static u64 rk_timer_counter_read(struct rk_timer *timer) return counter; } +static u64 rk_timer_counter_read(struct rk_timer *timer) +{ + return _rk_timer_counter_read(timer); +} + static void rk_timer_interrupt_clear(struct rk_timer *timer) { writel_relaxed(1, timer->base + TIMER_INT_STATUS); @@ -168,7 +173,7 @@ static u64 notrace rk_timer_sched_clock_read(void) { struct rk_clocksource *_cs = &cs_timer; - return ~rk_timer_counter_read(&_cs->timer); + return ~_rk_timer_counter_read(&_cs->timer); } static int __init rk_timer_init(struct device_node *np, u32 ctrl_reg) -- 1.7.9.5