From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DEBBB847E for ; Fri, 10 Mar 2023 13:50:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63F3EC4339B; Fri, 10 Mar 2023 13:50:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678456205; bh=dZQ8O/lixK/x52r5dkXXKOcPWOSVLerdV8exjH2PbDQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I6lTmoZEg2HZKcmYEfEDGhR2xe4pysVRWtKkPa53r4tHS/zmEuaaGDdc6INn0x1GJ fL92l1GYx9JZRD4Jz+khjUx3FrpmG9KRok32SoBR3T/M0XdnYsBiJGV/Zy5ukDXJdw hX3tW3JuQSfoMBUgXvqmNqfY1L+H9CAxyW7gAQGQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Johan Hovold , David Collins , Alexandre Belloni Subject: [PATCH 4.14 099/193] rtc: pm8xxx: fix set-alarm race Date: Fri, 10 Mar 2023 14:38:01 +0100 Message-Id: <20230310133714.546984489@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230310133710.926811681@linuxfoundation.org> References: <20230310133710.926811681@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Johan Hovold commit c88db0eff9722fc2b6c4d172a50471d20e08ecc6 upstream. Make sure to disable the alarm before updating the four alarm time registers to avoid spurious alarms during the update. Note that the disable needs to be done outside of the ctrl_reg_lock section to prevent a racing alarm interrupt from disabling the newly set alarm when the lock is released. Fixes: 9a9a54ad7aa2 ("drivers/rtc: add support for Qualcomm PMIC8xxx RTC") Cc: stable@vger.kernel.org # 3.1 Signed-off-by: Johan Hovold Reviewed-by: David Collins Link: https://lore.kernel.org/r/20230202155448.6715-2-johan+linaro@kernel.org Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-pm8xxx.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-) --- a/drivers/rtc/rtc-pm8xxx.c +++ b/drivers/rtc/rtc-pm8xxx.c @@ -235,7 +235,6 @@ static int pm8xxx_rtc_set_alarm(struct d { int rc, i; u8 value[NUM_8_BIT_RTC_REGS]; - unsigned int ctrl_reg; unsigned long secs, irq_flags; struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); const struct pm8xxx_rtc_regs *regs = rtc_dd->regs; @@ -247,6 +246,11 @@ static int pm8xxx_rtc_set_alarm(struct d secs >>= 8; } + rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl, + regs->alarm_en, 0); + if (rc) + return rc; + spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags); rc = regmap_bulk_write(rtc_dd->regmap, regs->alarm_rw, value, @@ -256,19 +260,11 @@ static int pm8xxx_rtc_set_alarm(struct d goto rtc_rw_fail; } - rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg); - if (rc) - goto rtc_rw_fail; - - if (alarm->enabled) - ctrl_reg |= regs->alarm_en; - else - ctrl_reg &= ~regs->alarm_en; - - rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl, ctrl_reg); - if (rc) { - dev_err(dev, "Write to RTC alarm control register failed\n"); - goto rtc_rw_fail; + if (alarm->enabled) { + rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl, + regs->alarm_en, regs->alarm_en); + if (rc) + goto rtc_rw_fail; } dev_dbg(dev, "Alarm Set for h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",