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bh=4tf5jp72b9mmtNlArsH2jcFwIQOwqOIebwrOBPuEsBU=; b=vW38oH58SUgN obs6SjJhClQIlWVFt7JcHZfQdjnkjCb9N/+lAkHP8fNp7szj9m9NYerZc44i1fW4rtjLyXFs7gCEG /NqD5jaufBVTwDzbgYNSL7CfNAmhuqPEa2y+olZQ8IwAlIcy/V2ut1x5W9OYHzF6l2JNgoT5z0DOl sqyAx5FU+VCnAliTFbOB6e3xSBCeF2G5vIBEnIi/Pby7JJfqANZigsl5/3kLiHA+wu+YopkkAWoj3 gVkBC9rkP9wdvzEA042rzbj3Aq8QeqNaCiEDd4icvPRrnGgPGSp/39WL75tWkdCQHVaW2WRJKfMSn yGLAeaOO1aPyLlSQ0gfUyg==; Received: from 108-223-40-66.lightspeed.sntcca.sbcglobal.net ([108.223.40.66]:37946 helo=server.roeck-us.net) by bh-25.webhostbox.net with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.100.1) (envelope-from ) id 1xLjPF-00000000Tie-1O4z; Tue, 27 Oct 2026 21:18:09 +0530 From: Guenter Roeck To: linux-watchdog@vger.kernel.org Cc: Tzung-Bi Shih , Guenter Roeck Subject: [PATCH v2 3/8] watchdog: core: Prevent ping worker from re-arming timer on suspend Date: Tue, 27 Oct 2026 08:48:00 -0700 Message-ID: <20261027154805.2518806-4-linux@roeck-us.net> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20261027154805.2518806-1-linux@roeck-us.net> References: <20261027154805.2518806-1-linux@roeck-us.net> X-Mailing-List: linux-watchdog@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-BWhitelist: no X-Source-IP: 108.223.40.66 X-Source-L: No X-Exim-ID: 1xLjPF-00000000Tie-1O4z X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 108-223-40-66.lightspeed.sntcca.sbcglobal.net (server.roeck-us.net) [108.223.40.66]:37946 X-Source-Auth: guenter@roeck-us.net X-Email-Count: 48 X-Org: HG=direseller_whb_net_legacy;ORG=directi; X-Source-Cap: cm9lY2s7YWN0aXZzdG07YmgtMjUud2ViaG9zdGJveC5uZXQ= X-Local-Domain: yes X-CMAE-Envelope: MS4xfJeUCrQ04ceV2c2s6Sgelvm8cmXkHhGYb/jiymcrl35TggH1BMQjIAUaWbsLiBnM8PQ4gowxlyQwv/t2xKuSfX5N6EdDGmGeqxBJCF0wDSX54UI6NX+X O2RMuG1xNDCgATQshslYqFRWCCDEENZUO16VvCV+9r1Lhvs6jR0yLyiC2MLKQ2dp4zjljf1nn3reQhyW8FVKBVjFmAorSk/y7zRLkeXAWS/o3I4HHEiYx1pQ In watchdog_dev_suspend(), hrtimer_cancel() is called before kthread_cancel_work_sync(). If the timer expired just before hrtimer_cancel() and queued watchdog_ping_work(), the worker can run and acquire wd_data->lock while kthread_cancel_work_sync() waits for it to finish. Because no state flag indicates that the watchdog is suspended, watchdog_worker_should_ping() returns true and __watchdog_ping() re-arms wd_data->timer while the device is suspended. Add a _WDOG_SUSPENDED internal status bit to wd_data->status, set it under wd_data->lock in watchdog_dev_suspend(), clear it under wd_data->lock in watchdog_dev_resume(), and check it in watchdog_worker_should_ping(), watchdog_need_worker(), and __watchdog_ping() so the timer cannot be armed while suspended. Fixes: 60bcd91aafd2 ("watchdog: introduce watchdog_dev_suspend/resume") Assisted-by: LLM Reviewed-by: Tzung-Bi Shih Signed-off-by: Guenter Roeck --- v2: Added Reviewed-by: tag drivers/watchdog/watchdog_core.h | 1 + drivers/watchdog/watchdog_dev.c | 15 +++++++++++---- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/watchdog/watchdog_core.h b/drivers/watchdog/watchdog_core.h index ab825d9f9248..c6df5a584357 100644 --- a/drivers/watchdog/watchdog_core.h +++ b/drivers/watchdog/watchdog_core.h @@ -60,6 +60,7 @@ struct watchdog_core_data { #define _WDOG_DEV_OPEN 0 /* Opened ? */ #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ #define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */ +#define _WDOG_SUSPENDED 3 /* Suspended ? */ }; /* diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 50224877ff49..e38f1ef8e683 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -81,6 +81,9 @@ static inline bool watchdog_need_worker(struct watchdog_device *wdd) unsigned int hm = wdd->max_hw_heartbeat_ms; unsigned int t = wdd->timeout * 1000; + if (test_bit(_WDOG_SUSPENDED, &wdd->wd_data->status)) + return false; + /* * A worker to generate heartbeat requests is needed if all of the * following conditions are true. @@ -154,9 +157,10 @@ static int __watchdog_ping(struct watchdog_device *wdd) now = ktime_get(); if (ktime_after(earliest_keepalive, now)) { - hrtimer_start(&wd_data->timer, - ktime_sub(earliest_keepalive, now), - HRTIMER_MODE_REL_HARD); + if (!test_bit(_WDOG_SUSPENDED, &wd_data->status)) + hrtimer_start(&wd_data->timer, + ktime_sub(earliest_keepalive, now), + HRTIMER_MODE_REL_HARD); return 0; } @@ -207,7 +211,7 @@ static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) { struct watchdog_device *wdd = wd_data->wdd; - if (!wdd) + if (!wdd || test_bit(_WDOG_SUSPENDED, &wd_data->status)) return false; if (watchdog_active(wdd)) @@ -1318,6 +1322,8 @@ int watchdog_dev_suspend(struct watchdog_device *wdd) mutex_lock(&wd_data->lock); if (watchdog_worker_should_ping(wd_data)) ret = __watchdog_ping(wd_data->wdd); + if (!ret) + set_bit(_WDOG_SUSPENDED, &wd_data->status); mutex_unlock(&wd_data->lock); if (ret) @@ -1346,6 +1352,7 @@ int watchdog_dev_resume(struct watchdog_device *wdd) * ping worker if needed. */ mutex_lock(&wd_data->lock); + clear_bit(_WDOG_SUSPENDED, &wd_data->status); if (watchdog_worker_should_ping(wd_data)) ret = __watchdog_ping(wd_data->wdd); mutex_unlock(&wd_data->lock); -- 2.45.2