Hi,
Static analysis with Coverity on linux-next today has detected an issue
in the following commit:
commit cc0ee20bd96971c10eba9a83ecf1c0733078a083
Author: Diana Craciun <diana.craciun@xxxxxxxxxxx>
Date: Mon Oct 5 20:36:52 2020 +0300
vfio/fsl-mc: trigger an interrupt via eventfd
The analysis is as follows:
106 static int vfio_fsl_mc_set_irq_trigger(struct vfio_fsl_mc_device *vdev,
107 unsigned int index, unsigned
int start,
108 unsigned int count, u32 flags,
109 void *data)
110 {
111 struct fsl_mc_device *mc_dev = vdev->mc_dev;
112 int ret, hwirq;
113 struct vfio_fsl_mc_irq *irq;
114 struct device *cont_dev = fsl_mc_cont_dev(&mc_dev->dev);
115 struct fsl_mc_device *mc_cont = to_fsl_mc_device(cont_dev);
116
cond_const: Condition count != 1U, taking false branch. Now the value of
count is equal to 1.
117 if (start != 0 || count != 1)
118 return -EINVAL;
119
120 mutex_lock(&vdev->reflck->lock);
121 ret = fsl_mc_populate_irq_pool(mc_cont,
122 FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
123 if (ret)
124 goto unlock;
125
126 ret = vfio_fsl_mc_irqs_allocate(vdev);
127 if (ret)
128 goto unlock;
129 mutex_unlock(&vdev->reflck->lock);
130
const: At condition count, the value of count must be equal to 1.
dead_error_condition: The condition !count cannot be true.
Logically dead code (DEADCODE)
dead_error_line: Execution cannot reach the expression flags & 1U inside
this statement: if (!count && flags & 1U)
....
131 if (!count && (flags & VFIO_IRQ_SET_DATA_NONE))
132 return vfio_set_trigger(vdev, index, -1);
At line 131, count is 1 because of the check and return on lines
117-118. !count is 0, and so 0 && (flags & VFIO_IRQ_SET_DATA_NONE) is
always false, so the vfio_set_trigger is never called. I suspect that
was not the intention.
Colin
