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authorAlexey Khoroshilov <khoroshilov@ispras.ru>2017-10-22 01:03:44 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-08 14:26:50 +0100
commitf53459c00871a7c3db5b69b49d840ca9d497a695 (patch)
tree8681cb2fabc0ae2344c867c885dc55cdccd6696a /drivers/w1/slaves
parentd4035a8c1ff7288af9e47d6d05384f14c9308ea1 (diff)
downloadlinux-f53459c00871a7c3db5b69b49d840ca9d497a695.tar.bz2
w1: keep balance of mutex locks and refcnts
w1_therm_eeprom() and w1_DS18B20_precision() decrement THERM_REFCNT on error paths, while they did not increment it yet. read_therm() unlocks bus mutex on some error paths, while it is not acquired. The patch makes sure all the functions keep the balance in usage of the mutex and the THERM_REFCNT. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/w1/slaves')
-rw-r--r--drivers/w1/slaves/w1_therm.c59
1 files changed, 31 insertions, 28 deletions
diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index 259525c3382a..3c350dfbcd0b 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -268,17 +268,18 @@ static inline int w1_therm_eeprom(struct device *device)
int ret, max_trying = 10;
u8 *family_data = sl->family_data;
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
- goto post_unlock;
-
if (!sl->family_data) {
ret = -ENODEV;
- goto pre_unlock;
+ goto error;
}
/* prevent the slave from going away in sleep */
atomic_inc(THERM_REFCNT(family_data));
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret != 0)
+ goto dec_refcnt;
+
memset(rom, 0, sizeof(rom));
while (max_trying--) {
@@ -306,17 +307,17 @@ static inline int w1_therm_eeprom(struct device *device)
sleep_rem = msleep_interruptible(tm);
if (sleep_rem != 0) {
ret = -EINTR;
- goto post_unlock;
+ goto dec_refcnt;
}
ret = mutex_lock_interruptible(&dev->bus_mutex);
if (ret != 0)
- goto post_unlock;
+ goto dec_refcnt;
} else if (!w1_strong_pullup) {
sleep_rem = msleep_interruptible(tm);
if (sleep_rem != 0) {
ret = -EINTR;
- goto pre_unlock;
+ goto mt_unlock;
}
}
@@ -324,11 +325,11 @@ static inline int w1_therm_eeprom(struct device *device)
}
}
-pre_unlock:
+mt_unlock:
mutex_unlock(&dev->bus_mutex);
-
-post_unlock:
+dec_refcnt:
atomic_dec(THERM_REFCNT(family_data));
+error:
return ret;
}
@@ -350,20 +351,22 @@ static inline int w1_DS18B20_precision(struct device *device, int val)
if (val > 12 || val < 9) {
pr_warn("Unsupported precision\n");
- return -1;
+ ret = -EINVAL;
+ goto error;
}
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
- goto post_unlock;
-
if (!sl->family_data) {
ret = -ENODEV;
- goto pre_unlock;
+ goto error;
}
/* prevent the slave from going away in sleep */
atomic_inc(THERM_REFCNT(family_data));
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret != 0)
+ goto dec_refcnt;
+
memset(rom, 0, sizeof(rom));
/* translate precision to bitmask (see datasheet page 9) */
@@ -411,11 +414,10 @@ static inline int w1_DS18B20_precision(struct device *device, int val)
}
}
-pre_unlock:
mutex_unlock(&dev->bus_mutex);
-
-post_unlock:
+dec_refcnt:
atomic_dec(THERM_REFCNT(family_data));
+error:
return ret;
}
@@ -490,17 +492,18 @@ static ssize_t read_therm(struct device *device,
int ret, max_trying = 10;
u8 *family_data = sl->family_data;
- ret = mutex_lock_interruptible(&dev->bus_mutex);
- if (ret != 0)
- goto error;
-
if (!family_data) {
ret = -ENODEV;
- goto mt_unlock;
+ goto error;
}
/* prevent the slave from going away in sleep */
atomic_inc(THERM_REFCNT(family_data));
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret != 0)
+ goto dec_refcnt;
+
memset(info->rom, 0, sizeof(info->rom));
while (max_trying--) {
@@ -542,7 +545,7 @@ static ssize_t read_therm(struct device *device,
sleep_rem = msleep_interruptible(tm);
if (sleep_rem != 0) {
ret = -EINTR;
- goto dec_refcnt;
+ goto mt_unlock;
}
}
@@ -567,10 +570,10 @@ static ssize_t read_therm(struct device *device,
break;
}
-dec_refcnt:
- atomic_dec(THERM_REFCNT(family_data));
mt_unlock:
mutex_unlock(&dev->bus_mutex);
+dec_refcnt:
+ atomic_dec(THERM_REFCNT(family_data));
error:
return ret;
}