Bug 232314 – Network process crash when fetching WebsiteDataType::ResourceLoadStatistics or calling webkit_website_data_manager_get_itp_summary() in ephemeral sessions

• Component: WebKit2
• Status: REOPENED

[Michael Catanzaro]

Reproducer: create an incognito mode window in Epiphany, open preferences, then open the personal data dialog. The network process will crash.

Detailed backtrace here: https://bugzilla-attachments.redhat.com/attachment.cgi?id=1837253&t=Coz3VzYSQm. That backtrace is for 2.32, but I've just reproduced with 2.34.1.

Problem is Epiphany fetches all types of website data, as is reasonable. NetworkProcess::fetchWebsiteData does this:

#if ENABLE(INTELLIGENT_TRACKING_PREVENTION)
    if (websiteDataTypes.contains(WebsiteDataType::ResourceLoadStatistics)) {
        if (auto* session = networkSession(sessionID)) {
            if (auto* resourceLoadStatistics = session->resourceLoadStatistics()) {
                resourceLoadStatistics->registrableDomains([callbackAggregator](auto&& domains) mutable {
                    while (!domains.isEmpty())
                        callbackAggregator->m_websiteData.registrableDomainsWithResourceLoadStatistics.add(domains.takeLast());
                });
            }
        }
    }
#endif

The call to WebResourceLoadStatisticsStore::registrableDomains calls WebResourceLoadStatisticsStore::postTask, and that does this:

// Resource load statistics should not be captured for ephemeral sessions.
RELEASE_ASSERT(!isEphemeral());

Oops. We either need an early return in NetworkProcess::fetchWebsiteData, or perhaps better in WebResourceLoadStatisticsStore::registrableDomains? Or maybe it would be better if NetworkSession::resourceLoadStatistics would return nullptr rather than a valid WebResourceLoadStatisticsStore when we have an ephemeral session? Or for NetworkSession::setResourceLoadStatisticsEnabled to never be called in the first place? That's ultimately triggered via WebsiteDataStore::parameters and WebsiteDataStore::setResourceLoadStatisticsEnabled. Maybe that would be the right place to force it to false for ephemeral sessions?

[Radar WebKit Bug Importer]

<rdar://problem/84934873>

[Michael Catanzaro]

Hi John, any preferences on how to fix this? If not, I'll probably go for a localized fix in NetworkProcess::fetchWebsiteData.

[Michael Catanzaro]

I can't reproduce this anymore, not with trunk and not with 2.34.1 either. I'm not sure when this somehow got fixed.

[Michael Catanzaro]

Actually I can reproduce with 2.34.1, but not with trunk. Going to leave this closed.

[Michael Catanzaro]

Reopening because I just hit this again today. Updated backtrace looks like:

#0  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
#1  0x00007f0afd29af83 in __pthread_kill_internal (threadid=<optimized out>, signo=6) at pthread_kill.c:78
#2  0x00007f0afd24208e in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#3  0x00007f0afd229882 in __GI_abort () at abort.c:79
#4  0x00007f0afdae8ddf in WTFCrashWithInfo () at WTF/Headers/wtf/Assertions.h:864
#5  0x00007f0afdd9ae36 in WebKit::WebResourceLoadStatisticsStore::postTask (this=0x7f0ae3018400, task=<optimized out>)
    at /buildstream/gnome/sdk/webkitgtk-6.0.bst/Source/WebKit/NetworkProcess/Classifier/WebResourceLoadStatisticsStore.cpp:201
#6  WebKit::WebResourceLoadStatisticsStore::aggregatedThirdPartyData (this=0x7f0ae3018400, completionHandler=<optimized out>)
    at /buildstream/gnome/sdk/webkitgtk-6.0.bst/Source/WebKit/NetworkProcess/Classifier/WebResourceLoadStatisticsStore.cpp:1561
...

I'll omit the rest of the backtrace because it's just this release assert:

inline void WebResourceLoadStatisticsStore::postTask(WTF::Function<void()>&& task)
{
    // Resource load statistics should not be captured for ephemeral sessions.
    RELEASE_ASSERT(!isEphemeral());

It's reproducible by opening Epiphany's Privacy Report dialog in a private browsing window, which calls webkit_website_data_manager_get_itp_summary(). Apparently that's guaranteed to crash the network process if called for an ephemeral session? I suppose the WebKit API will need to guard against this usage somewhere.

[Michael Catanzaro]

*** Bug 290391 has been marked as a duplicate of this bug. ***