From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) (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 0B38A38FAD; Fri, 29 Nov 2024 23:20:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732922444; cv=none; b=eV4dSv1ZU6gb83mZSwmdAntbsWjT4ohy+oROVHd7xVpVJv+6Wy/l/YgiGX6Bar3zM5LgsuJ5ZCL8OC719hhIZcgieGPYGoWLl03qi7+F+y6iFduKSZiM2ULDEl7Gag3PVmIn2mul08tEKmMAYbcuj0i1oTXWbIc1IEJhcraiZjI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732922444; c=relaxed/simple; bh=tVQpUbUALSzFeHsjelEz0sCEXGf2z8kbyz1EmkfnlJo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=S6+ObXbo/ASrzb81smfL+hKPxJFiwqXbPMtoEYbR6pykmUEuVx0kEDtOeHPq1xBauhDLE93SzFFLPyGvV/m/6X8Ok6OkkwdEqfhohRUPzipYo01hbwU28PJ6WMFWYBA7viOeViSlPF1OecbyvIDc9NTfUrkQifRhSpWr3YRZBpo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=SR4i4O0s; arc=none smtp.client-ip=217.70.183.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="SR4i4O0s" Received: by mail.gandi.net (Postfix) with ESMTPSA id 9D8FC40003; Fri, 29 Nov 2024 23:20:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1732922439; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=q0vCYdInPo1Dg1M0c/jQNcugfGfoOVsoCMaIFPdkpec=; b=SR4i4O0srbQJl4PoKMmJD/iwW7lfpgRzk6l4s2poRkmT5d+8yCi78fkmiAwSW28ENQgTA/ C6vc+TNkpACFFM9dQ8P6oQiLx5I7q5UU7v7ZTt3xSEYzEgbQBXG9jMF2930qn5sp3EahMl NG/RbBVvA5JpQl8jBevb4kg9I0trJ8C8nqcJepENycFCXRlr5/6tzDcWglf3nBAD6IGdfF hAG0IhskQf+wVjjnd6HxEV0u+qUtEI+8iuH/T0p3gb49RyjYMYRmpDPd8iWrbdgKYZijmD Dt6Na5K5w4q6R3f85Jnr89x8B8VRgeqHsHJJSSdnOPIeuerAsJbCdXlmIWFWPg== Date: Sat, 30 Nov 2024 00:20:38 +0100 From: Alexandre Belloni To: =?utf-8?B?6auY5rC46Imv?= Cc: john.stultz@linaro.org, linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org, Yongliang Gao , Jingqun Li Subject: Re: [PATCH] rtc: check if __rtc_read_time was successful in rtc_timer_do_work() Message-ID: <20241129232038ad3be3ae@mail.local> References: <20241011043153.3788112-1-leonylgao@gmail.com> <173136306889.3322178.5149197946199507685.b4-ty@bootlin.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-GND-Sasl: alexandre.belloni@bootlin.com On 20/11/2024 22:17:34+0800, 高永良 wrote: > Hi Alexandre Belloni, > > I've noticed that the post-failure process for __rtc_read_time requires > careful handling. > 1. Need to call pm_relax. I had a look when taking your patch and I'm not convinced calling pm_relax is necessary. > 2. Potentially need to set the alarm to ensure subsequent interrupts can > process the > expired timer? Could you give me some advice? Same thing, if you are not able to read the current time, setting the next alarm is going to fail anyway. > Should I continue to submit a fix patch or create a v2 version of the patch? > > Best Regards, > Yongliang Gao > > Alexandre Belloni 于2024年11月12日周二 06:11写道： > > > On Fri, 11 Oct 2024 12:31:53 +0800, Yongliang Gao wrote: > > > If the __rtc_read_time call fails,, the struct rtc_time tm; may contain > > > uninitialized data, or an illegal date/time read from the RTC hardware. > > > > > > When calling rtc_tm_to_ktime later, the result may be a very large value > > > (possibly KTIME_MAX). If there are periodic timers in rtc->timerqueue, > > > they will continually expire, may causing kernel softlockup. > > > > > > [...] > > > > Applied, thanks! > > > > [1/1] rtc: check if __rtc_read_time was successful in rtc_timer_do_work() > > https://git.kernel.org/abelloni/c/e8ba8a2bc4f6 > > > > Best regards, > > > > -- > > Alexandre Belloni, co-owner and COO, Bootlin > > Embedded Linux and Kernel engineering > > https://bootlin.com > > -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com