NRE in Networking Telemetry EventSources #77434

Closed
#86171
Closed
NRE in Networking Telemetry EventSources#77434
#86171
Labels
area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
Milestone
8.0.0

Description

@MihaZupan
MihaZupan
opened on Oct 25, 2022

EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.

If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
This race condition only appears once per process.

I believe this is the cause of an exception YARP hit in CI:

System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

We should fix these cases.

cc: @Tratcher aspnetcore has 2 such cases as well:
https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46

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(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

      Skip to content
      NRE in Networking Telemetry EventSources #77434
      Closed
      #86171
      Closed
      NRE in Networking Telemetry EventSources#77434
      #86171
      Labels
      area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
      Milestone
      8.0.0
      Description
      @MihaZupan
      MihaZupan
      opened on Oct 25, 2022
      EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
      
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.
      If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
      
This race condition only appears once per process.
      I believe this is the cause of an exception YARP hit in CI:
      System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

      We should fix these cases.
      cc: @Tratcher aspnetcore has 2 such cases as well:
      https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
      https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46
      Metadata
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, 'i');
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})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

          Skip to content
          NRE in Networking Telemetry EventSources #77434
          Closed
          #86171
          Closed
          NRE in Networking Telemetry EventSources#77434
          #86171
          Labels
          area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
          Milestone
          8.0.0
          Description
          @MihaZupan
          MihaZupan
          opened on Oct 25, 2022
          EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
          
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.
          If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
          
This race condition only appears once per process.
          I believe this is the cause of an exception YARP hit in CI:
          System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

          We should fix these cases.
          cc: @Tratcher aspnetcore has 2 such cases as well:
          https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
          https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46
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, 'i');
if (__m === '*' || __re.test(location.href)) {
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} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              NRE in Networking Telemetry EventSources #77434
              Closed
              #86171
              Closed
              NRE in Networking Telemetry EventSources#77434
              #86171
              Labels
              area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
              Milestone
              8.0.0
              Description
              @MihaZupan
              MihaZupan
              opened on Oct 25, 2022
              EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
              
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.
              If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
              
This race condition only appears once per process.
              I believe this is the cause of an exception YARP hit in CI:
              System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

              We should fix these cases.
              cc: @Tratcher aspnetcore has 2 such cases as well:
              https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
              https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
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var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
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});
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}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
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observer.observe(document.body, { childList: true, subtree: true });
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})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

                  Skip to content
                  NRE in Networking Telemetry EventSources #77434
                  Closed
                  #86171
                  Closed
                  NRE in Networking Telemetry EventSources#77434
                  #86171
                  Labels
                  area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
                  Milestone
                  8.0.0
                  Description
                  @MihaZupan
                  MihaZupan
                  opened on Oct 25, 2022
                  EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
                  
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.
                  If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
                  
This race condition only appears once per process.
                  I believe this is the cause of an exception YARP hit in CI:
                  System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

                  We should fix these cases.
                  cc: @Tratcher aspnetcore has 2 such cases as well:
                  https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
                  https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46
                  Metadata
                  Metadata
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                    Type
                    No type
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                    No projects
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                      None yet
                      Development
                      No branches or pull requests
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
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function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
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if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                      Skip to content
                      NRE in Networking Telemetry EventSources #77434
                      Closed
                      #86171
                      Closed
                      NRE in Networking Telemetry EventSources#77434
                      #86171
                      Labels
                      area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
                      Milestone
                      8.0.0
                      Description
                      @MihaZupan
                      MihaZupan
                      opened on Oct 25, 2022
                      EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
                      
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.
                      If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
                      
This race condition only appears once per process.
                      I believe this is the cause of an exception YARP hit in CI:
                      System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

                      We should fix these cases.
                      cc: @Tratcher aspnetcore has 2 such cases as well:
                      https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
                      https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46
                      Metadata
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                          No branches or pull requests
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
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observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
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} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                          Skip to content
                          NRE in Networking Telemetry EventSources #77434
                          Closed
                          #86171
                          Closed
                          NRE in Networking Telemetry EventSources#77434
                          #86171
                          Labels
                          area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
                          Milestone
                          8.0.0
                          Description
                          @MihaZupan
                          MihaZupan
                          opened on Oct 25, 2022
                          EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
                          
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.
                          If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
                          
This race condition only appears once per process.
                          I believe this is the cause of an exception YARP hit in CI:
                          System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

                          We should fix these cases.
                          cc: @Tratcher aspnetcore has 2 such cases as well:
                          https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
                          https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46
                          Metadata
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                              None yet
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                              No branches or pull requests
                              Issue actions
                              
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
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[data-theme="light"], [data-theme="light"],
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.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

                              Skip to content
                              NRE in Networking Telemetry EventSources #77434
                              Closed
                              #86171
                              Closed
                              NRE in Networking Telemetry EventSources#77434
                              #86171
                              Labels
                              area-System.Netbugtenet-reliabilityReliability/stability related issue (stress, load problems, etc.)
                              Milestone
                              8.0.0
                              Description
                              @MihaZupan
                              MihaZupan
                              opened on Oct 25, 2022
                              EventSource.IsEnabled() may start returning true before the OnEventCommand completes.
                              
We initialize shared EventCounter instances in OnEventCommand that we then use from instrumented code paths.
                              If the EventSource is initialized before being enabled, and the instance is accessed from multiple threads, a thread could see IsEnabled() == true and then read a nullEventCounter instance.
                              
This race condition only appears once per process.
                              I believe this is the cause of an exception YARP hit in CI:
                              System.NullReferenceException : Object reference not set to an instance of an object.
at System.Net.Http.HttpTelemetry.Http11RequestLeftQueue(Double timeOnQueueMilliseconds)
at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)

                              We should fix these cases.
                              cc: @Tratcher aspnetcore has 2 such cases as well:
                              https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/Middleware/ConcurrencyLimiter/src/ConcurrencyLimiterEventSource.cs#L47
                              https://github.com/dotnet/aspnetcore/blob/1e8fe7e4ba93935ebc10aee6ef2a4d2b3b0c05d9/src/SignalR/common/Http.Connections/src/Internal/HttpConnectionsEventSource.cs#L46
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