User Agent: Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:92.0) Gecko/20100101 Firefox/92.0

Steps to reproduce:

Since I upgraded to Fedora 35, Firefox's DRM plugin crashes every single time.
Interestingly, this does only happen when using the rpm but not when using the flatpak.
This was also working correctly in Fedora 34.

I reproduced with FF 91 and 92.

STR:

1. Open https://bitmovin.com/demos/drm
2. Observe the crash

Downstream bug: https://bugzilla.redhat.com/show_bug.cgi?id=2002833

Actual results:

The DRM plugin crashes. Here is the link to one of the crash reports.

https://crash-stats.mozilla.org/signature/?product=Firefox&signature=libxul.so%400x19e695e%20%7C%20libxul.so%400xc80efa%20%7C%20plugin-container%400x49e89&date=%3E%3D2021-09-03T04%3A32%3A00.000Z&date=%3C2021-09-10T04%3A32%3A00.000Z&_columns=date&_columns=product&_columns=version&_columns=build_id&_columns=platform&_columns=reason&_columns=address&_columns=install_time&_columns=startup_crash&_sort=-date&page=1#summary

Backtrace

(gdb) thread apply all bt full

Thread 2 (Thread 0x7f8ba0f93640 (LWP 56681)):
warning: Section `.reg-xstate/56681' in core file too small.
#0 syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
No locals.
#1 0x00007f8ba61ebf8e in epoll_wait () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#2 0x00007f8ba61eb7d7 in event_base_loop () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#3 0x00007f8ba61e48a6 in base::MessagePumpLibevent::Run(base::MessagePump::Delegate*) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#4 0x00007f8ba65a2f0c in MessageLoop::Run() () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#5 0x00007f8ba65a7a7d in base::Thread::ThreadMain() () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#6 0x00007f8ba65a250b in ThreadFunc(void*) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#7 0x00007f8ba31a1aaf in start_thread (arg=<optimized out>) at pthread_create.c:434
ret = <optimized out>
pd = <optimized out>
out = <optimized out>
unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140237677868608, -7683175635257608486, 140237677868608, 14, 140237713578112, 0, 7658548762172241626, 7658553976174196442}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
not_first_call = <optimized out>
#8 0x00007f8ba3226300 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
No locals.

Thread 1 (Thread 0x7f8ba0f9a0c0 (LWP 56678)):
#0 0x00007f8ba507d95e in mozilla::gmp::GMPChild::ProcessingError(mozilla::ipc::HasResultCodes::Result, char const*) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#1 0x00007f8ba4317efb in mozilla::ipc::IPCResult::Fail(mozilla::NotNull<mozilla::ipc::IProtocol*>, char const*, char const*) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#2 0x00007f8ba5085f91 in mozilla::gmp::GMPChild::AnswerStartPlugin(nsTString<char16_t> const&) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#3 0x00007f8ba43af7ef in mozilla::gmp::PGMPChild::OnCallReceived(IPC::Message const&, IPC::Message*&) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#4 0x00007f8ba4315ab2 in mozilla::ipc::MessageChannel::DispatchInterruptMessage(mozilla::ipc::ActorLifecycleProxy*, IPC::Message&&, unsigned long) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#5 0x00007f8ba430dcc5 in mozilla::ipc::MessageChannel::DispatchMessage(IPC::Message&&) [clone .cold] () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#6 0x00007f8ba61ef100 in mozilla::ipc::MessageChannel::MessageTask::Run() () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#7 0x00007f8ba61e4ab0 in MessageLoop::DoWork() () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#8 0x00007f8ba65a4ccf in base::MessagePumpDefault::Run(base::MessagePump::Delegate*) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#9 0x00007f8ba65a2f0c in MessageLoop::Run() () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#10 0x00007f8ba71cbd40 in XRE_InitChildProcess(int, char**, XREChildData const*) () from /usr/lib64/firefox/libxul.so
No symbol table info available.
#11 0x000055679ac19a0b in content_process_main(mozilla::Bootstrap*, int, char**) ()
No symbol table info available.
#12 0x000055679ac0b393 in main ()
No symbol table info available.

Expected results:

No crash, play the DRM content.

The Bugbug bot thinks this bug should belong to the 'Core::Audio/Video: Playback' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.