Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

Nicky726 · Yesterday 09:18:13

Since the upgrade of qt6-webengine to 6.11.2-1 I am get crashes of QtWebEngineProcess trigger in:
- Falkon by accessing certain webpages (e.g. https://k-report.net/), works just fine for others (e.g. https://bbs.archlinux.org/). There is a high CPU load for a while, then a standard "error when loading a webpage" appears together with:

říj 07 11:11:24 asaborake systemd-coredump[58370]: [?] Process 58325 (QtWebEngineProc) of user 1000 dumped core.
                                                     
                                                     Stack trace of thread 1:
                                                     #0  0x00007fe630313e69 n/a (n/a + 0x0)
                                                     ELF object binary architecture: AMD x86-64

I supect theese are also related,as they started to appearch at that time:
- Akonadi-EWS sometimes reporting <e-mail> source is damaged, hitting check e-mail in Kontact (once or twice) resumes normal operation, other times it just works normally,
- Krusader KIO-Webdavs by accessing certain folders (some folders are listed ok, for other it hangs -- surprisingly, killing some kio_http.so process then causes folder listing to appear, same applies for copying files from webdavs).

Deleting .cache did not help. These issues appear on all my Arch computers and also for all my users. KDE with X11.

Is anyone experiencing the issue? Any ideas what to try?

(https://bugs.kde.org/ returns Forbidden...)

Lone_Wolf · Yesterday 11:15:34

Same with falkon on lxqt/openbox/X11 , so it's not kde specific .

qt6-webengine was last updated on august 20, are you sure that's when the issues started ?

Konqueror also uses qt6-webengine and should be able to show websites, does it have the same problem ?

SimonJ · Yesterday 11:30:02

In qutebrowser I get this, if it helps?

Nicky726 · Yesterday 12:43:16

Lone_Wolf wrote:

qt6-webengine was last updated on august 20, are you sure that's when the issues started ?
Konqueror also uses qt6-webengine and should be able to show websites, does it have the same problem ?

Yes, in Konqueror the page also crashes QtWebEngineProcess.

I am sure with the date/upgrade that pulled qt6-webengine=6.11.2-1, I just didn't got to looking into it during summer.

As for webdavs (for Active directory shared folders), I have a wider window: It was OK may/june, it was KO september, didn't use it in between.

seth · Yesterday 13:22:05

Looks like the stack was corrupted. Does it first ramp up RSS consumption?
Try to attach GDB to the process before triggering the crash, do not allow it to get there but interrupt the execution immediately™ and check what the stack looks like (w/ debuginfod)

Nicky726 · Yesterday 16:30:21

Sadly, no luck. Both "gdb falkon" as well as attaching gdb to a running falkon (or its QtWebEngineProcess) results in a crash of gdb... The same goes for gdbing konqueror.

I have some coredumps, however, I guess such an output is not very helpful?

# coredumpctl debug 70303
           PID: 70303 (QtWebEngineProc)
           TID: 70303 (QtWebEngineProc)
           UID: 1000 (nik)
           GID: 100 (users)
        Signal: 5 (TRAP) si_code: SI_KERNEL
     Timestamp: Wed 2026-10-07 18:03:24 CEST (12min ago)
  Command Line: $'/usr/lib/qt6/QtWebEngineProcess --type=renderer --webengine-schemes=error:lL;konq:lL;tar:lL;bookmarks:lL;ghelp:lL;help:lL;info:lL;man:lL;exec:l;qrc:sV --webengine-locales-path=/usr/share/qt6/translations/qtwebengine_locales --webengine-resources-path=/usr/share/qt6/resources --disable-speech-api --touch-events=auto --disable-blink-features=EyeDropperAPI,WebOTP,DocumentPictureInPictureAPI --lang=cs --num-raster-threads=4 --enable-main-frame-before-activation --renderer-client-id=4 --time-ticks-at-unix-epoch=-1791344172434251 --launch-time-ticks=44832312308 --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,699158597529548565,5925077413429474822,262144 --enable-features=NetworkServiceInProcess2,TracingServiceInProcess,WebRTCPipeWireCapturer --disable-features=BackgroundFetch,EyeDropper,InstalledApp,WebOTP,WebPayments,WebUSB,kSanitizeOriginalUrlDuringNavigation --variations-seed-version'
    Executable: /usr/lib/qt6/QtWebEngineProcess
 Control Group: /user.slice/user-1000.slice/user@1000.service/app.slice/app-konqbrowser@dcb93b1443d842bdaee9f16b68cd1682.service
          Unit: user@1000.service
     User Unit: app-konqbrowser@dcb93b1443d842bdaee9f16b68cd1682.service
         Slice: user-1000.slice
     Owner UID: 1000 (nik)
       Boot ID: 7db24673724d48599553154f4be3022f
    Machine ID: 1e1450babc374e18be4b9c8338bf011b
      Hostname: asaborake
       Storage: /var/lib/systemd/coredump/core.QtWebEngineProc.1000.7db24673724d48599553154f4be3022f.70303.1791389004000000.zst (truncated)
  Size on Disk: 1.1M
       Message: Process 70303 (QtWebEngineProc) of user 1000 dumped core.
                
                Stack trace of thread 1:
                #0  0x00007f581af13e69 n/a (n/a + 0x0)
                ELF object binary architecture: AMD x86-64

GNU gdb (GDB) 18.1
<...>
Reading symbols from /usr/lib/qt6/QtWebEngineProcess...

This GDB supports auto-downloading debuginfo from the following URLs:
  <https://debuginfod.archlinux.org>
Enable debuginfod for this session? (y or [n]) y
Debuginfod has been enabled.
To make this setting permanent, add 'set debuginfod enabled on' to .gdbinit.
Reading symbols from /root/.cache/debuginfod_client/d2f39848fa78cd69104f750d4704fdc1d0b06b8f/debuginfo...

⚠ warning: BFD: warning: /var/tmp/coredump-0A1SbE has a segment extending past end of file

⚠ warning: Can't open file /dev/shm/.org.chromium.Chromium.HS2ROp (deleted) during file-backed mapping note processing

⚠ warning: Can't open file /dev/shm/.org.chromium.Chromium.LTagtb (deleted) during file-backed mapping note processing

⚠ warning: Can't open file /dev/shm/.org.chromium.Chromium.q47e7a (deleted) during file-backed mapping note processing

⚠ warning: Can't open file /dev/shm/.org.chromium.Chromium.aAM8fo (deleted) during file-backed mapping note processing

⚠ warning: core file may not match specified executable file.
[New LWP 1 (id 1)]
[New LWP 8 (id 2)]
[New LWP 7 (id 3)]
[New LWP 3 (id 4)]
[New LWP 2 (id 5)]
[New LWP 4 (id 6)]
[New LWP 5 (id 7)]
[New LWP 6 (id 8)]

⚠ warning: failed to parse execution context from corefile: Cannot access memory at address 0x7ffef577cfd8
❌ Failed to read a valid object file image from memory.
Core was generated by `/usr/lib/qt6/QtWebEngineProcess --type=renderer --webengine-schemes=error:lL;ko'.
Program terminated with signal SIGTRAP, Trace/breakpoint trap.
#0  0x00007f581af13e69 in ?? ()

seth · Yesterday 19:37:54

results in a crash of gdb

seth wrote:

Does it first ramp up RSS consumption?

ie are you losing memory fast?

Do you get the same error inside the browser as the screenshot in #3 ?
Does it help to disable javascript?

Nicky726 · Today 09:28:02

seth wrote:

Does it first ramp up RSS consumption? ie are you losing memory fast?

No, there is no great loss of memory, and there is plenty of free memory available:

#Pre-webpage-access
$ free
               total        used        free      shared  buff/cache   available
Mem:        32424336     7961928    16274028     2066528    10810280    24462408
Swap:       67108860     3832632    63276228
#Post-webpage-access
$ free
               total        used        free      shared  buff/cache   available
Mem:        32424336     7985864    16141004     2097664    10950512    24438472
Swap:       67108860     3832628    63276232

(This is with disabled systemd-coredump. With it enabled there is high CPU and memory load, which I guess is expected.)

seth wrote:

Do you get the same error inside the browser as the screenshot in #3 ?

Not, quite, Falkon displays a general "Error when loading webpage message", without any details. Konqueor displays nothing.

seth wrote:

Does it help to disable javascript?

It does not, neither in Falkon, nor in Konqueror.

I also tried disabling AddBlock in Falkon, which also had not impact.

Arch Linux

#1 Yesterday 09:18:13

Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

#2 Yesterday 11:15:34

Re: Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

#3 Yesterday 11:30:02

Re: Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

#4 Yesterday 12:43:16

Re: Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

#5 Yesterday 13:22:05

Re: Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

#6 Yesterday 16:30:21

Re: Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

#7 Yesterday 19:37:54

Re: Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

#8 Today 09:28:02

Re: Crashes of QtWebEngineProcess (Falkon/Akonadi-EWS/KIO-Webdav)

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