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authorMichael Brunner <mibru@gmx.de>2009-08-26 14:29:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-26 20:06:52 -0700
commit0d288162f2afc42b37aab656f4622c076babbca3 (patch)
tree6dcac3abf329692ead0cd71d63c8ffa3fd88d63f /drivers
parent4ab6c08336535f8c8e42cf45d7adeda882eff06e (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')
-rw-r--r--drivers/thermal/thermal_sys.c9
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)