6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ziyan Fu fuzy5@lenovo.com
[ Upstream commit 40efc43eb7ffb5a4e2f998c13b8cfb555e671b92 ]
The driver probes with the invalid timeout value when 'iTCO_wdt_set_timeout()' fails, as its return value is not checked. In this case, when executing "wdctl", we may get:
Device: /dev/watchdog0 Timeout: 30 seconds Timeleft: 613 seconds
The timeout value is the value of "heartbeat" or "WATCHDOG_TIMEOUT", and the timeleft value is calculated from the register value we actually read (0xffff) by masking with 0x3ff and converting ticks to seconds (* 6 / 10).
Add error handling to return the failure code if 'iTCO_wdt_set_timeout()' fails, ensuring the driver probe fails and prevents invalid operation.
Signed-off-by: Ziyan Fu fuzy5@lenovo.com Reviewed-by: Guenter Roeck linux@roeck-us.net Link: https://lore.kernel.org/r/20250704073518.7838-1-13281011316@163.com Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Wim Van Sebroeck wim@linux-watchdog.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/watchdog/iTCO_wdt.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c index dd297dcd524c..68973be2ce62 100644 --- a/drivers/watchdog/iTCO_wdt.c +++ b/drivers/watchdog/iTCO_wdt.c @@ -601,7 +601,11 @@ static int iTCO_wdt_probe(struct platform_device *pdev) /* Check that the heartbeat value is within it's range; if not reset to the default */ if (iTCO_wdt_set_timeout(&p->wddev, heartbeat)) { - iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT); + ret = iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT); + if (ret != 0) { + dev_err(dev, "Failed to set watchdog timeout (%d)\n", WATCHDOG_TIMEOUT); + return ret; + } dev_info(dev, "timeout value out of range, using %d\n", WATCHDOG_TIMEOUT); }