From 56c1d32323e773b8b927316f8beeae9238576335 Mon Sep 17 00:00:00 2001 From: Tom Verdonck Date: Fri, 25 Sep 2026 20:23:22 +0200 Subject: [PATCH] hwmon: (tmp102) Fix jiffies wraparound in conversion-ready check tmp102 records a one-shot deadline in ->ready_time at probe (and resume) and, on every temperature read, refuses the read with -EAGAIN while time_before(jiffies, ready_time) is true, in order to skip the first ~35 ms conversion. ->ready_time is an unsigned long compared with time_before(), whose signed difference is only meaningful while the two values are within LONG_MAX jiffies of each other. Because ->ready_time is set once and never refreshed, jiffies keeps advancing away from it, and after 2^31 jiffies the difference flips sign. On a 32-bit HZ=100 kernel that happens ~248.5 days after boot: time_before() then permanently reports "not ready" and the driver returns -EAGAIN on every read, without ever touching the sensor, until the next reboot. Store the deadline as a 64-bit jiffies value and compare it with get_jiffies_64()/time_before64(), which does not wrap in any practical uptime. Fixes: 3d8f7a89a197 ("hwmon: (tmp102) Improve handling of initial read delay") Cc: stable@vger.kernel.org Signed-off-by: Tom Verdonck Link: https://patch.msgid.link/2952f070f82913aea96eec25d28008d3b9058656.1790358356.git.tom.verdonck@inspiral.be Signed-off-by: Guenter Roeck --- drivers/hwmon/tmp102.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c index 50a8b050d8da..8c8463ddb6c4 100644 --- a/drivers/hwmon/tmp102.c +++ b/drivers/hwmon/tmp102.c @@ -58,7 +58,7 @@ struct tmp102 { const char *label; struct regmap *regmap; u16 config_orig; - unsigned long ready_time; + u64 ready_time; u16 sample_time; }; @@ -106,7 +106,7 @@ static int tmp102_read_temp(struct device *dev, u32 attr, long *val) switch (attr) { case hwmon_temp_input: /* Is it too early to return a conversion ? */ - if (time_before(jiffies, tmp102->ready_time)) { + if (time_before64(get_jiffies_64(), tmp102->ready_time)) { dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__); return -EAGAIN; } @@ -354,7 +354,7 @@ static int tmp102_probe(struct i2c_client *client) * Mark that we are not ready with data until the first * conversion is complete */ - tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS); + tmp102->ready_time = get_jiffies_64() + msecs_to_jiffies(CONVERSION_TIME_MS); hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, tmp102, @@ -387,7 +387,7 @@ static int tmp102_resume(struct device *dev) err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG, TMP102_CONF_SD, 0); - tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS); + tmp102->ready_time = get_jiffies_64() + msecs_to_jiffies(CONVERSION_TIME_MS); return err; }