cgroup.go: avoid panic on nil interface #207
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| @@ -323,6 +323,9 @@ func (c *cgroup) Tasks(subsystem Name, recursive bool) ([]Task, error) { | |||
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| func (c *cgroup) processes(subsystem Name, recursive bool, pType procType) ([]Process, error) { | |||
| s := c.getSubsystem(subsystem) | |||
| if s == nil { | |||
| return nil, ErrControllerNotActive | |||
| } | |||
| sp, err := c.path(subsystem) | |||
| if err != nil { | |||
| return nil, err | |||
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I was rethinking that error message. I think the following code might be more clear for the error
After Line 329,
if s == nil {
return nil, errors.Errorf("no such cgroup %s in subsystem %s", sp, subsystem)
}
WDYT?
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Could we define a new Error with this?
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os.ErrNotExist for errors.Wrapf ?
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I think os.ErrNotExist is fine 😃
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I was thinking something like
var ErrCgroupNotInSubsystem = errors.New("cgroups: cgroup not in subsystem")
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I was thinking something like
var ErrCgroupNotInSubsystem = errors.New("cgroups: cgroup not in subsystem")
The error doesn't contain the which subsystem and which cgroup. That is My concern
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Yes, we should make it clear
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Could we use fmt.Errorf("cgroups: %s doesn't exist in %s subsystem", sp, subsystem) ?
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Could we use
fmt.Errorf("cgroups: %s doesn't exist in %s subsystem", sp, subsystem)?
sgtm
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Signed-off-by: linrl3 <[email protected]>
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Hi, this PR's related issue is #205, which is a potential nil interface panic case.
In https://github.com/containerd/cgroups/blob/main/cgroup.go#L330, if we pass a subsystem that doesn't exist into func (c *cgroup) Processes(subsystem Name, recursive bool), we would get a panic: interface conversion: interface is nil, not cgroups.pather.
So we'd check nil interface and return error if it's nil to avoid panic.