Bug 498378 - k3b crashes on startup with SIGBUS when trying to load libwidevinecdm.so from local Firefox profile
Summary: k3b crashes on startup with SIGBUS when trying to load libwidevinecdm.so from...
Status: RESOLVED DOWNSTREAM
Alias: None
Product: k3b
Classification: Applications
Component: general (other bugs)
Version First Reported In: 24.12.0
Platform: Debian testing Linux
: NOR crash
Target Milestone: ---
Assignee: K3b Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-01-08 08:06 UTC by Aurélien COUDERC
Modified: 2025-02-16 17:36 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


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Description Aurélien COUDERC 2025-01-08 08:06:38 UTC
Dear maintainers,

k3b is crashing with with SIGBUS when trying to load libwidevinecdm.so from the local Firefox profile directory.

A workaround is to set the environment variable QTWEBENGINE_CHROMIUM_FLAGS=--widevine-path=/does-not-exist

This was reported as Debian bug #1091642 [1].

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1091642


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Debian testing 
KDE Plasma Version: 6.2.4
KDE Frameworks Version: 6.8
Qt Version: 6.7.2

ADDITIONAL INFORMATION
Logs :
===============================================================================
QGuiApplication::setDesktopFileName: the specified desktop file name ends with
.desktop. For compatibility reasons, the .desktop suffix will be removed.
Please specify a desktop file name without .desktop suffix
kf.coreaddons.kaboutdata: QGuiApplication::desktopFileName "org.kde.k3b" is
out-of-sync with KAboutData::applicationData().desktopFileName
"org.kde.k3b.desktop"
QGuiApplication::setDesktopFileName: the specified desktop file name ends with
.desktop. For compatibility reasons, the .desktop suffix will be removed.
Please specify a desktop file name without .desktop suffix
21 21
kf.coreaddons.kaboutdata: QGuiApplication::desktopFileName "org.kde.k3b" is
out-of-sync with KAboutData::applicationData().desktopFileName
"org.kde.k3b.desktop"
[124210:124210:1228/225345.267939:FATAL:zygote_host_impl_linux.cc(208)] Check
failed: . : No such file or directory (2)
fish: Job 1, 'k3b' terminated by signal SIGTRAP (Trace or breakpoint trap)
===============================================================================

Stack :
Thread 1 "k3b" received signal SIGTRAP, Trace/breakpoint trap.
0x00007fffed93a914 in logging::LogMessage::~LogMessage() () from
/lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
(gdb) bt
#0  0x00007fffed93a914 in logging::LogMessage::~LogMessage() () at
/lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#1  0x00007fffed93aa11 in logging::ErrnoLogMessage::~ErrnoLogMessage() ()
at /lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#2  0x00007fffed93e0aa in logging::CheckError::~CheckError() () at
/lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#3  0x00007fffecb05277 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  0x00007fffed1f4b0a in content::(anonymous
namespace)::LaunchZygoteHelper(base::CommandLine*, base::ScopedGeneric<int,
base::internal::ScopedFDCloseTraits>*) () at
/lib/x86_64-linux-gnu/libQt6WebEngineCore.so.6
#5  0x00007fffebf8ed11 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  0x00007fffebf2d785 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 ??? ()
Comment 1 Albert Astals Cid 2025-01-08 16:09:57 UTC
This is clearly not a k3b problem, we're not debian nor firefox nor webengine/chromium there's nothing we can do here.

I suggest you add more debug symbols so you get debug info on libQt6WebEngineCore and possibly report a bug against the debian webengine package since it seems what may be at fault here (or the Qt6 webengine code upstream).
Comment 2 Aurélien COUDERC 2025-01-08 16:48:02 UTC
Hmm, so k3b crashing on startup is not a k3b problem, oh well…

I’ll try confirming with the original reporter if that happens with other webengine-enabled apps and get more symbols as you suggested.

Thanks
Comment 3 Albert Astals Cid 2025-01-08 17:46:36 UTC
I don't understand why you are upset, there's literally nothing we can do in k3b code to fix this problem (other than not using qtwebengine).

Do it is not a k3b bug.

It also "works for me" so it points to either a bug in qtwebengine, or in how debian compiled qtwebengine, again nothing we can fix.
Comment 4 Aurélien COUDERC 2025-02-16 17:36:16 UTC
For the record you were right that it has nothing to do with k3b specifically.

The user had a corrupt widevine library in their browser config which caused the crash.

It still looks very fragile to me and I’d be surprise if you cannot somehow attack that to inject random code into apps using qtwebengine.