Hi,
> Could you try launching other apps that build against the Qt6 WebEngine widgets library and report back if you get crashes or not ? Running "apt rdepends libqt6webenginewidgets6" will give you some ideas (parley, ktorrent…).
I tested a few packages reported by "apt rdepends libqt6webenginewidgets6". During the tests, I unset the environment variable QTWEBENGINE_CHROMIUM_FLAGS.
- The following applications work fine: akregator, khelpcenter, konqueror, kontact, notedeln, parley.
- The following applications crash at startup with the same output: falkon, k3b, ktorrent, pageedit, privacybrowser, recoll, sigil, tellico, zeal.
I also verified each time that setting "QTWEBENGINE_CHROMIUM_FLAGS=--widevine-path=/does-not-exist" fixes the crash issue and allows the applications above to work fine.
> Could you install more debug packages to get a complete stack of the crash ?
I executed "QTWEBENGINE_CHROMIUM_FLAGS= DEBUGINFOD_URLS=https://debuginfod.debian.net gdb k3b". I allowed symbol downloads, and I run the program. I got the exact same back trace as the one I reported before, but here it is again:===============================================================================
[1938130:1938130:0108/193358.925123:FATAL:zygote_host_impl_linux.cc(208)] Check failed: . : No such file or directory (2)
Thread 1 "k3b" received signal SIGTRAP, Trace/breakpoint trap.
0x00007fffed949914 in logging::LogMessage::~LogMessage() () from /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
(gdb) bt
#0 0x00007fffed949914 in logging::LogMessage::~LogMessage() () at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#1 0x00007fffed949a11 in logging::ErrnoLogMessage::~ErrnoLogMessage() () at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#2 0x00007fffed94d0aa in logging::CheckError::~CheckError() () at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#3 0x00007fffecb134f7 in content::ZygoteHostImpl::LaunchZygote(base::CommandLine*, base::ScopedGeneric<int, base::internal::ScopedFDCloseTraits>*, std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >) () at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#4 0x00007fffed203b0a in content::(anonymous namespace)::LaunchZygoteHelper(base::CommandLine*, base::ScopedGeneric<int, base::internal::ScopedFDCloseTraits>*) () at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#5 0x00007fffebf9cfb1 in content::ZygoteCommunication::Init(base::OnceCallback<int (base::CommandLine*, base::ScopedGeneric<int, base::internal::ScopedFDCloseTraits>*)>) () at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#6 0x00007fffebf3b785 in content::CreateGenericZygote(base::OnceCallback<int (base::CommandLine*, base::ScopedGeneric<int, base::internal::ScopedFDCloseTraits>*)>) () at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#7 0x0000000000000030 in ??? ()
#8 0x0000000000000000 in ??? ()===============================================================================
As far as I understand, the back trace doesn't show where the actual issue is, because that error (ENOENT errno) happens in a child process, which is the one that actually tries to load libwidevinecdm.so and crashes, and that crash leads to content::ZygoteHostImpl::LaunchZygote failing.
For the moment, I added the following to my /etc/environment, until some update fixes the issue.
===============================================================================
# Avoid loading libwidevinecdm.so which causes SIGBUS crashes.
QTWEBENGINE_CHROMIUM_FLAGS=--widevine-path=/does-not-exist
===============================================================================