From: "Heiko Stübner" <heiko@sntech.de>
To: Alexander Kochetkov <al.kochet@gmail.com>
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org,
Thomas Gleixner <tglx@linutronix.de>,
Mark Rutland <mark.rutland@arm.com>,
Rob Herring <robh+dt@kernel.org>,
Russell King <linux@armlinux.org.uk>,
Caesar Wang <wxt@rock-chips.com>,
Huang Tao <huangtao@rock-chips.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>
Subject: Re: [PATCH v3 13/13] clocksource/drivers/rockchip_timer: Prevent ftrace recursion
Date: Tue, 29 Nov 2016 16:01:09 +0100 [thread overview]
Message-ID: <7837485.H9nfDmPu0F@diego> (raw)
In-Reply-To: <1480427118-5126-14-git-send-email-al.kochet@gmail.com>
Am Dienstag, 29. November 2016, 16:45:18 schrieb Alexander Kochetkov:
> 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 <al.kochet@gmail.com>
you introduced the issue yourself in patch 11/13. In general any patch should
never leave the kernel in a worse state than it was before, so no patch should
ever introduce known issues itself.
In that line of thought, don't patches 10+11 introduce warnings about unused
functions as well when applied without patch 12?
Maybe merge them?
Heiko
> ---
> 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)
WARNING: multiple messages have this Message-ID (diff)
From: "Heiko Stübner" <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
To: Alexander Kochetkov <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Russell King <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>,
Caesar Wang <wxt-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
Huang Tao <huangtao-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
Daniel Lezcano
<daniel.lezcano-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH v3 13/13] clocksource/drivers/rockchip_timer: Prevent ftrace recursion
Date: Tue, 29 Nov 2016 16:01:09 +0100 [thread overview]
Message-ID: <7837485.H9nfDmPu0F@diego> (raw)
In-Reply-To: <1480427118-5126-14-git-send-email-al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Am Dienstag, 29. November 2016, 16:45:18 schrieb Alexander Kochetkov:
> 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 <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
you introduced the issue yourself in patch 11/13. In general any patch should
never leave the kernel in a worse state than it was before, so no patch should
ever introduce known issues itself.
In that line of thought, don't patches 10+11 introduce warnings about unused
functions as well when applied without patch 12?
Maybe merge them?
Heiko
> ---
> 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)
--
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WARNING: multiple messages have this Message-ID (diff)
From: heiko@sntech.de (Heiko Stübner)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 13/13] clocksource/drivers/rockchip_timer: Prevent ftrace recursion
Date: Tue, 29 Nov 2016 16:01:09 +0100 [thread overview]
Message-ID: <7837485.H9nfDmPu0F@diego> (raw)
In-Reply-To: <1480427118-5126-14-git-send-email-al.kochet@gmail.com>
Am Dienstag, 29. November 2016, 16:45:18 schrieb Alexander Kochetkov:
> 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 <al.kochet@gmail.com>
you introduced the issue yourself in patch 11/13. In general any patch should
never leave the kernel in a worse state than it was before, so no patch should
ever introduce known issues itself.
In that line of thought, don't patches 10+11 introduce warnings about unused
functions as well when applied without patch 12?
Maybe merge them?
Heiko
> ---
> 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)
next prev parent reply other threads:[~2016-11-29 15:03 UTC|newest]
Thread overview: 147+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-28 14:31 [PATCHv2 00/11] Implement clocksource for rockchip SoC using rockchip timer Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 01/11] dt-bindings: clarify compatible property for rockchip timers Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 02/11] ARM: dts: rockchip: update compatible property for rk3228 timer Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 03/11] ARM: dts: rockchip: update compatible property for rk3229 timer Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 04/11] ARM: dts: rockchip: add timer entries to rk3188 dtsi Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 05/11] clocksource/drivers/rockchip_timer: split bc_timer into rk_timer and rk_clock_event_device Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 06/11] clocksource/drivers/rockchip_timer: low level routines take rk_timer as parameter Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 07/11] clocksource/drivers/rockchip_timer: drop unused rk_base() and rk_ctrl() Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 08/11] clocksource/drivers/rockchip_timer: move TIMER_INT_UNMASK out of rk_timer_enable() Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 09/11] clocksource/drivers/rockchip_timer: implement loading 64bit value into timer Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 10/11] clocksource/drivers/rockchip_timer: implement reading 64bit value from timer Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` [PATCHv2 11/11] clocksource/drivers/rockchip_timer: implement clocksource timer Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-28 14:31 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 00/13] Implement clocksource for rockchip SoC using rockchip timer Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 01/13] dt-bindings: clarify compatible property for rockchip timers Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 02/13] ARM: dts: rockchip: update compatible property for rk3228 timer Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 03/13] ARM: dts: rockchip: update compatible property for rk3229 timer Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 04/13] ARM: dts: rockchip: add timer entries to rk3188 dtsi Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 05/13] ARM: dts: rockchip: disable arm-global-timer for rk3188 Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 06/13] clocksource/drivers/rockchip_timer: split bc_timer into rk_timer and rk_clock_event_device Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 07/13] clocksource/drivers/rockchip_timer: low level routines take rk_timer as parameter Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 08/13] clocksource/drivers/rockchip_timer: drop unused rk_base() and rk_ctrl() Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 15:03 ` Heiko Stübner
2016-11-29 15:03 ` Heiko Stübner
2016-11-29 15:03 ` Heiko Stübner
2016-11-29 13:45 ` [PATCH v3 09/13] clocksource/drivers/rockchip_timer: move TIMER_INT_UNMASK out of rk_timer_enable() Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 10/13] clocksource/drivers/rockchip_timer: implement loading 64bit value into timer Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 11/13] clocksource/drivers/rockchip_timer: implement reading 64bit value from timer Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 12/13] clocksource/drivers/rockchip_timer: implement clocksource timer Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` [PATCH v3 13/13] clocksource/drivers/rockchip_timer: Prevent ftrace recursion Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 13:45 ` Alexander Kochetkov
2016-11-29 15:01 ` Heiko Stübner [this message]
2016-11-29 15:01 ` Heiko Stübner
2016-11-29 15:01 ` Heiko Stübner
2016-11-29 15:36 ` Alexander Kochetkov
2016-11-29 15:36 ` Alexander Kochetkov
2016-11-29 15:36 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 0/9] Implement clocksource for rockchip SoC using rockchip timer Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 1/9] dt-bindings: clarify compatible property for rockchip timers Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-12-05 22:22 ` Rob Herring
2016-12-05 22:22 ` Rob Herring
2016-12-05 22:22 ` Rob Herring
2016-11-29 16:14 ` [PATCH v4 2/9] ARM: dts: rockchip: update compatible property for rk3228 timer Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2017-01-23 15:40 ` Daniel Lezcano
2017-01-23 15:40 ` Daniel Lezcano
2017-01-23 15:40 ` Daniel Lezcano
2017-01-23 16:12 ` Heiko Stübner
2017-01-23 16:12 ` Heiko Stübner
2017-01-23 16:12 ` Heiko Stübner
2017-01-23 16:13 ` Alexander Kochetkov
2017-01-23 16:13 ` Alexander Kochetkov
2017-01-23 16:13 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 3/9] ARM: dts: rockchip: update compatible property for rk3229 timer Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 4/9] ARM: dts: rockchip: add timer entries to rk3188 SoC Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 5/9] ARM: dts: rockchip: disable arm-global-timer for rk3188 Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2017-01-23 16:14 ` Heiko Stübner
2017-01-23 16:14 ` Heiko Stübner
2016-11-29 16:14 ` [PATCH v4 6/9] clocksource/drivers/rockchip_timer: split bc_timer into rk_timer and rk_clock_event_device Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2017-01-23 16:26 ` Daniel Lezcano
2017-01-23 16:26 ` Daniel Lezcano
2017-01-23 16:45 ` Alexander Kochetkov
2017-01-23 16:45 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 7/9] clocksource/drivers/rockchip_timer: low level routines take rk_timer as parameter Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 8/9] clocksource/drivers/rockchip_timer: move TIMER_INT_UNMASK out of rk_timer_enable() Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2016-11-29 16:14 ` [PATCH v4 9/9] clocksource/drivers/rockchip_timer: implement clocksource timer Alexander Kochetkov
2016-11-29 16:14 ` Alexander Kochetkov
2017-01-23 17:09 ` Heiko Stübner
2017-01-23 17:09 ` Heiko Stübner
2016-12-21 14:21 ` [PATCH v4 0/9] Implement clocksource for rockchip SoC using rockchip timer Alexander Kochetkov
2016-12-21 14:21 ` Alexander Kochetkov
2016-12-21 14:21 ` Alexander Kochetkov
2017-01-23 14:47 ` Daniel Lezcano
2017-01-23 14:47 ` Daniel Lezcano
2017-01-23 14:47 ` Daniel Lezcano
2017-01-23 17:12 ` Heiko Stübner
2017-01-23 17:12 ` Heiko Stübner
2017-01-23 17:24 ` Alexander Kochetkov
2017-01-23 17:24 ` Alexander Kochetkov
2017-01-23 17:24 ` Alexander Kochetkov
2017-01-23 17:57 ` Daniel Lezcano
2017-01-23 17:57 ` Daniel Lezcano
2017-01-26 11:08 ` Alexander Kochetkov
2017-01-26 11:08 ` Alexander Kochetkov
2017-01-26 11:08 ` Alexander Kochetkov
2017-01-26 13:19 ` Daniel Lezcano
2017-01-26 13:19 ` Daniel Lezcano
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