diff options
| author | Michael Brunner <mibru@gmx.de> | 2009-08-26 14:29:25 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-08-26 20:06:52 -0700 |
| commit | 0d288162f2afc42b37aab656f4622c076babbca3 (patch) | |
| tree | 6dcac3abf329692ead0cd71d63c8ffa3fd88d63f /drivers/thermal | |
| parent | 4ab6c08336535f8c8e42cf45d7adeda882eff06e (diff) | |
thermal_sys: check get_temp return value
The return value of the get_temp function is not checked when doing a
thermal zone update. This may lead to a critical shutdown if get_temp
fails and the content of the temp variable is incorrectly set higher than
the critical trip point.
This has been observed on a system with incorrect ACPI implementation
where the corresponding methods were not serialized and therefore
sometimes triggered ACPI errors (AE_ALREADY_EXISTS). The following
critical shutdowns indicated a temperature of 2097 C, which was obviously
wrong.
The patch adds a return value check that jumps over all trip point
evaluations printing a warning if get_temp fails. The trip points are
evaluated again on the next polling interval with successful get_temp
execution.
Signed-off-by: Michael Brunner <mibru@gmx.de>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/thermal')
| -rw-r--r-- | drivers/thermal/thermal_sys.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c index 0a69672097a..4e83c297ec9 100644 --- a/drivers/thermal/thermal_sys.c +++ b/drivers/thermal/thermal_sys.c @@ -953,7 +953,12 @@ void thermal_zone_device_update(struct thermal_zone_device *tz) mutex_lock(&tz->lock); - tz->ops->get_temp(tz, &temp); + if (tz->ops->get_temp(tz, &temp)) { + /* get_temp failed - retry it later */ + printk(KERN_WARNING PREFIX "failed to read out thermal zone " + "%d\n", tz->id); + goto leave; + } for (count = 0; count < tz->trips; count++) { tz->ops->get_trip_type(tz, count, &trip_type); @@ -1005,6 +1010,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz) THERMAL_TRIPS_NONE); tz->last_temperature = temp; + + leave: if (tz->passive) thermal_zone_device_set_polling(tz, tz->passive_delay); else if (tz->polling_delay) |