21 lines
1.5 KiB
Markdown
21 lines
1.5 KiB
Markdown
|
# InvalidOperationException in ASP.Net-RecycleLimitMonitor-AlertProxyMonitors
|
||
|
|
|
||
|
|
## Symptoms
|
||
|
|
ASP.Net applications may crash intermittently due to an `InvalidOperationException` in
|
||
|
|
`System_Web_ni!System.Web.Hosting.RecycleLimitMonitor+RecycleLimitMonitorSingleton.AlertProxyMonitors`.
|
||
|
|
|
||
|
|
## Cause
|
||
|
|
This issue was introduced when ASP.Net 4.7 separated cache management and memory monitoring. This new `RecycleLimitMonitorSingleton` monitors worker process private bytes usage against the recycling limit for the process, and when
|
||
|
|
the limit is near, it alerts a set of "proxy monitors" in each registered AppDomain so they can take action to avoid a process
|
||
|
|
recycle. The collection of "proxy monitors" being enumerated was not thread-safe, though, so new AppDomains spinning up or old
|
||
|
|
AppDomains shutting down while this monitor enumerated the collection could result in this unhandled `InvalidOperationException`
|
||
|
|
in the default AppDomain, causing a crash.
|
||
|
|
|
||
|
|
## Workaround
|
||
|
|
There is no reliable workaround. If the environment does not tend to consume private bytes near the recycling limit, or if
|
||
|
|
web app domain lifetimes tend to last the entire length of the process lifetime, then chances of hitting this issue are
|
||
|
|
extremely minimal. More private bytes consumption and/or more AppDomain recycling increases the odds of hitting this exception condition.
|
||
|
|
|
||
|
|
## Resolution
|
||
|
|
A hotfix for this issue is planned for .Net 4.8. This page will be updated with a link to the hotfix when it becomes available.
|