From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: linux-kernel@vger.kernel.org, a.zummo@towertech.it,
Pan Bian <bianpan2016@163.com>,
Guy Shapiro <guy.shapiro@mobi-wize.com>,
Stefan Agner <stefan@agner.ch>, Frank Li <Frank.Li@freescale.com>,
Shawn Guo <shawn.guo@linaro.org>,
linux-rtc@vger.kernel.org, "# v3 . 16+" <stable@vger.kernel.org>
Subject: Re: [RESEND] [PATCH] rtc: snvs: Fix usage of snvs_rtc_enable
Date: Tue, 3 Apr 2018 16:56:42 +0200 [thread overview]
Message-ID: <20180403145642.GA6444@piout.net> (raw)
In-Reply-To: <1522264445-2398-1-git-send-email-pure.logic@nexus-software.ie>
On 28/03/2018 20:14:05+0100, Bryan O'Donoghue wrote:
> commit 179a502f8c46 ("rtc: snvs: add Freescale rtc-snvs driver") introduces
> the SNVS RTC driver with a function snvs_rtc_enable().
>
> snvs_rtc_enable() can return an error on the enable path however this
> driver does not currently trap that failure on the probe() path and
> consequently if enabling the RTC fails we encounter a later error spinning
> forever in rtc_write_sync_lp().
>
> [ 36.093481] [<c010d630>] (__irq_svc) from [<c0c2e9ec>] (_raw_spin_unlock_irqrestore+0x34/0x44)
> [ 36.102122] [<c0c2e9ec>] (_raw_spin_unlock_irqrestore) from [<c072e32c>] (regmap_read+0x4c/0x5c)
> [ 36.110938] [<c072e32c>] (regmap_read) from [<c085d0f4>] (rtc_write_sync_lp+0x6c/0x98)
> [ 36.118881] [<c085d0f4>] (rtc_write_sync_lp) from [<c085d160>] (snvs_rtc_alarm_irq_enable+0x40/0x4c)
> [ 36.128041] [<c085d160>] (snvs_rtc_alarm_irq_enable) from [<c08567b4>] (rtc_timer_do_work+0xd8/0x1a8)
> [ 36.137291] [<c08567b4>] (rtc_timer_do_work) from [<c01441b8>] (process_one_work+0x28c/0x76c)
> [ 36.145840] [<c01441b8>] (process_one_work) from [<c01446cc>] (worker_thread+0x34/0x58c)
> [ 36.153961] [<c01446cc>] (worker_thread) from [<c014aee4>] (kthread+0x138/0x150)
> [ 36.161388] [<c014aee4>] (kthread) from [<c0107e14>] (ret_from_fork+0x14/0x20)
> [ 36.168635] rcu_sched kthread starved for 2602 jiffies! g496 c495 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
> [ 36.178564] rcu_sched R running task 0 8 2 0x00000000
> [ 36.185664] [<c0c288b0>] (__schedule) from [<c0c29134>] (schedule+0x3c/0xa0)
> [ 36.192739] [<c0c29134>] (schedule) from [<c0c2db80>] (schedule_timeout+0x78/0x4e0)
> [ 36.200422] [<c0c2db80>] (schedule_timeout) from [<c01a7ab0>] (rcu_gp_kthread+0x648/0x1864)
> [ 36.208800] [<c01a7ab0>] (rcu_gp_kthread) from [<c014aee4>] (kthread+0x138/0x150)
> [ 36.216309] [<c014aee4>] (kthread) from [<c0107e14>] (ret_from_fork+0x14/0x20)
>
> This patch fixes by parsing the result of rtc_write_sync_lp() and
> propagating both in the probe and elsewhere. If the RTC doesn't start we
> don't proceed loading the driver and don't get into this loop mess later
> on.
>
> Fixes: 179a502f8c46 ("rtc: snvs: add Freescale rtc-snvs driver")
>
> Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
> Cc: a.zummo@towertech.it
> Cc: alexandre.belloni@free-electrons.com
> Cc: Pan Bian <bianpan2016@163.com>
> Cc: Guy Shapiro <guy.shapiro@mobi-wize.com>
> Cc: Stefan Agner <stefan@agner.ch>
> Cc: Frank Li <Frank.Li@freescale.com>
> Cc: Shawn Guo <shawn.guo@linaro.org>
> Cc: linux-rtc@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: <stable@vger.kernel.org> # v3.16+
> ---
> drivers/rtc/rtc-snvs.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
Applied, thanks.
--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
prev parent reply other threads:[~2018-04-03 14:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-28 19:14 [RESEND] [PATCH] rtc: snvs: Fix usage of snvs_rtc_enable Bryan O'Donoghue
2018-03-29 0:12 ` [RESEND] " Trent Piepho
2018-03-29 1:53 ` Bryan O'Donoghue
2018-03-30 22:59 ` Trent Piepho
2018-04-02 22:51 ` Bryan O'Donoghue
2018-04-03 14:42 ` Alexandre Belloni
2018-03-29 2:18 ` [RESEND] [PATCH] " Shawn Guo
2018-04-03 14:56 ` Alexandre Belloni [this message]
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