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([2a01:e0a:982:cbb0:f54e:4b0a:5175:5727]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3718985a347sm10025259f8f.60.2024.08.19.02.16.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 19 Aug 2024 02:16:17 -0700 (PDT) Message-ID: Date: Mon, 19 Aug 2024 11:16:16 +0200 Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Neil Armstrong Reply-To: neil.armstrong@linaro.org Subject: Re: [PATCH 2/3] usb: typec: ucsi: Move unregister out of atomic section To: Bjorn Andersson , Sebastian Reichel , Bjorn Andersson , Konrad Dybcio , Heikki Krogerus , Greg Kroah-Hartman Cc: Johan Hovold , Chris Lew , Dmitry Baryshkov , Stephen Boyd , Amit Pundir , linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, stable@vger.kernel.org References: <20240818-pmic-glink-v6-11-races-v1-0-f87c577e0bc9@quicinc.com> <20240818-pmic-glink-v6-11-races-v1-2-f87c577e0bc9@quicinc.com> Content-Language: en-US, fr Autocrypt: addr=neil.armstrong@linaro.org; keydata= xsBNBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB AAHNKk5laWwgQXJtc3Ryb25nIDxuZWlsLmFybXN0cm9uZ0BsaW5hcm8ub3JnPsLAkQQTAQoA OwIbIwULCQgHAwUVCgkICwUWAgMBAAIeAQIXgBYhBInsPQWERiF0UPIoSBaat7Gkz/iuBQJk Q5wSAhkBAAoJEBaat7Gkz/iuyhMIANiD94qDtUTJRfEW6GwXmtKWwl/mvqQtaTtZID2dos04 YqBbshiJbejgVJjy+HODcNUIKBB3PSLaln4ltdsV73SBcwUNdzebfKspAQunCM22Mn6FBIxQ GizsMLcP/0FX4en9NaKGfK6ZdKK6kN1GR9YffMJd2P08EO8mHowmSRe/ExAODhAs9W7XXExw UNCY4pVJyRPpEhv373vvff60bHxc1k/FF9WaPscMt7hlkbFLUs85kHtQAmr8pV5Hy9ezsSRa GzJmiVclkPc2BY592IGBXRDQ38urXeM4nfhhvqA50b/nAEXc6FzqgXqDkEIwR66/Gbp0t3+r yQzpKRyQif3OwE0ETVkGzwEIALyKDN/OGURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYp QTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXMcoJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+ SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hiSvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY 4yG6xI99NIPEVE9lNBXBKIlewIyVlkOaYvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoM Mtsyw18YoX9BqMFInxqYQQ3j/HpVgTSvmo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUX oUk33HEAEQEAAcLAXwQYAQIACQUCTVkGzwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfn M7IbRuiSZS1unlySUVYu3SD6YBYnNi3G5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa3 3eDIHu/zr1HMKErm+2SD6PO9umRef8V82o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCS KmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy 4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJC3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTT QbM0WUIBIcGmq38+OgUsMYu4NzLu7uZFAcmp6h8g Organization: Linaro In-Reply-To: <20240818-pmic-glink-v6-11-races-v1-2-f87c577e0bc9@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 19/08/2024 01:17, Bjorn Andersson wrote: > Commit 'caa855189104 ("soc: qcom: pmic_glink: Fix race during > initialization")' moved the pmic_glink client list under a spinlock, as > it is accessed by the rpmsg/glink callback, which in turn is invoked > from IRQ context. > > This means that ucsi_unregister() is now called from IRQ context, which > isn't feasible as it's expecting a sleepable context. An effort is under > way to get GLINK to invoke its callbacks in a sleepable context, but > until then lets schedule the unregistration. > > A side effect of this is that ucsi_unregister() can now happen > after the remote processor, and thereby the communication link with it, is > gone. pmic_glink_send() is amended with a check to avoid the resulting > NULL pointer dereference, but it becomes expecting to see a failing send > upon shutting down the remote processor (e.g. during a restart following > a firmware crash): > > ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5 > > Fixes: caa855189104 ("soc: qcom: pmic_glink: Fix race during initialization") > Cc: stable@vger.kernel.org > Signed-off-by: Bjorn Andersson > --- > drivers/soc/qcom/pmic_glink.c | 10 +++++++++- > drivers/usb/typec/ucsi/ucsi_glink.c | 28 +++++++++++++++++++++++----- > 2 files changed, 32 insertions(+), 6 deletions(-) > > diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c > index 58ec91767d79..e4747f1d3da5 100644 > --- a/drivers/soc/qcom/pmic_glink.c > +++ b/drivers/soc/qcom/pmic_glink.c > @@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_register_client); > int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len) > { > struct pmic_glink *pg = client->pg; > + int ret; > > - return rpmsg_send(pg->ept, data, len); > + mutex_lock(&pg->state_lock); > + if (!pg->ept) > + ret = -ECONNRESET; > + else > + ret = rpmsg_send(pg->ept, data, len); > + mutex_unlock(&pg->state_lock); > + > + return ret; > } > EXPORT_SYMBOL_GPL(pmic_glink_send); > > diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c > index ac53a81c2a81..a33056eec83d 100644 > --- a/drivers/usb/typec/ucsi/ucsi_glink.c > +++ b/drivers/usb/typec/ucsi/ucsi_glink.c > @@ -68,6 +68,9 @@ struct pmic_glink_ucsi { > > struct work_struct notify_work; > struct work_struct register_work; > + spinlock_t state_lock; > + unsigned int pdr_state; > + unsigned int new_pdr_state; > > u8 read_buf[UCSI_BUF_SIZE]; > }; > @@ -244,8 +247,22 @@ static void pmic_glink_ucsi_notify(struct work_struct *work) > static void pmic_glink_ucsi_register(struct work_struct *work) > { > struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work); > + unsigned long flags; > + unsigned int new_state; > + > + spin_lock_irqsave(&ucsi->state_lock, flags); > + new_state = ucsi->new_pdr_state; > + spin_unlock_irqrestore(&ucsi->state_lock, flags); > + > + if (ucsi->pdr_state != SERVREG_SERVICE_STATE_UP) { > + if (new_state == SERVREG_SERVICE_STATE_UP) > + ucsi_register(ucsi->ucsi); > + } else { > + if (new_state == SERVREG_SERVICE_STATE_DOWN) > + ucsi_unregister(ucsi->ucsi); > + } > > - ucsi_register(ucsi->ucsi); > + ucsi->pdr_state = new_state; > } > > static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) > @@ -269,11 +286,12 @@ static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) > static void pmic_glink_ucsi_pdr_notify(void *priv, int state) > { > struct pmic_glink_ucsi *ucsi = priv; > + unsigned long flags; > > - if (state == SERVREG_SERVICE_STATE_UP) > - schedule_work(&ucsi->register_work); > - else if (state == SERVREG_SERVICE_STATE_DOWN) > - ucsi_unregister(ucsi->ucsi); > + spin_lock_irqsave(&ucsi->state_lock, flags); > + ucsi->new_pdr_state = state; > + spin_unlock_irqrestore(&ucsi->state_lock, flags); > + schedule_work(&ucsi->register_work); > } > > static void pmic_glink_ucsi_destroy(void *data) > Looks good, I'll run it on the 8550/8650 platforms Reviewed-by: Neil Armstrong