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authorAaron Hill <aa1ronham@gmail.com>2018-12-24 14:23:36 -0500
committerZhang Rui <rui.zhang@intel.com>2019-01-18 15:23:04 +0800
commit129699bb8c7572106b5bbb2407c2daee4727ccad (patch)
treedb0c6f3b102bae69131935b851967a4cd983fa0f /drivers/thermal
parent3fe931b31a4078395c1967f0495dcc9e5ec6b5e3 (diff)
drivers: thermal: int340x_thermal: Fix sysfs race condition
Changes since V1: * Use dev_info instead of printk * Use dev_warn instead of BUG_ON Previously, sysfs_create_group was called before all initialization had fully run - specifically, before pci_set_drvdata was called. Since the sysctl group is visible to userspace as soon as sysfs_create_group returns, a small window of time existed during which a process could read from an uninitialized/partially-initialized device. This commit moves the creation of the sysctl group to after all initialized is completed. This ensures that it's impossible for userspace to read from a sysctl file before initialization has fully completed. To catch any future regressions, I've added a check to ensure that proc_thermal_emum_mode is never PROC_THERMAL_NONE when a process tries to read from a sysctl file. Previously, the aforementioned race condition could result in the 'else' branch running while PROC_THERMAL_NONE was set, leading to a null pointer deference. Signed-off-by: Aaron Hill <aa1ronham@gmail.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Diffstat (limited to 'drivers/thermal')
-rw-r--r--drivers/thermal/intel/int340x_thermal/processor_thermal_device.c28
1 files changed, 15 insertions, 13 deletions
diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
index 8e0f665cf06f..8e1cf4d789be 100644
--- a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
@@ -84,7 +84,12 @@ static ssize_t power_limit_##index##_##suffix##_show(struct device *dev, \
struct pci_dev *pci_dev; \
struct platform_device *pdev; \
struct proc_thermal_device *proc_dev; \
-\
+ \
+ if (proc_thermal_emum_mode == PROC_THERMAL_NONE) { \
+ dev_warn(dev, "Attempted to get power limit before device was initialized!\n"); \
+ return 0; \
+ } \
+ \
if (proc_thermal_emum_mode == PROC_THERMAL_PLATFORM_DEV) { \
pdev = to_platform_device(dev); \
proc_dev = platform_get_drvdata(pdev); \
@@ -298,11 +303,6 @@ static int proc_thermal_add(struct device *dev,
*priv = proc_priv;
ret = proc_thermal_read_ppcc(proc_priv);
- if (!ret) {
- ret = sysfs_create_group(&dev->kobj,
- &power_limit_attribute_group);
-
- }
if (ret)
return ret;
@@ -316,8 +316,7 @@ static int proc_thermal_add(struct device *dev,
proc_priv->int340x_zone = int340x_thermal_zone_add(adev, ops);
if (IS_ERR(proc_priv->int340x_zone)) {
- ret = PTR_ERR(proc_priv->int340x_zone);
- goto remove_group;
+ return PTR_ERR(proc_priv->int340x_zone);
} else
ret = 0;
@@ -331,9 +330,6 @@ static int proc_thermal_add(struct device *dev,
remove_zone:
int340x_thermal_zone_remove(proc_priv->int340x_zone);
-remove_group:
- sysfs_remove_group(&proc_priv->dev->kobj,
- &power_limit_attribute_group);
return ret;
}
@@ -364,7 +360,10 @@ static int int3401_add(struct platform_device *pdev)
platform_set_drvdata(pdev, proc_priv);
proc_thermal_emum_mode = PROC_THERMAL_PLATFORM_DEV;
- return 0;
+ dev_info(&pdev->dev, "Creating sysfs group for PROC_THERMAL_PLATFORM_DEV\n");
+
+ return sysfs_create_group(&pdev->dev.kobj,
+ &power_limit_attribute_group);
}
static int int3401_remove(struct platform_device *pdev)
@@ -441,7 +440,10 @@ static int proc_thermal_pci_probe(struct pci_dev *pdev,
dev_err(&pdev->dev, "No auxiliary DTSs enabled\n");
}
- return 0;
+ dev_info(&pdev->dev, "Creating sysfs group for PROC_THERMAL_PCI\n");
+
+ return sysfs_create_group(&pdev->dev.kobj,
+ &power_limit_attribute_group);
}
static void proc_thermal_pci_remove(struct pci_dev *pdev)