On Fri, Mar 19, 2021 at 12:04:56AM -0500, Douglas R. Reno via blfs-book wrote:
> On Thu, Mar 18, 2021 at 11:33 PM ken--- via blfs-book <
> blfs-book@lists.linuxfromscratch.org> wrote:
>
> > Author: ken
> > Date: Thu Mar 18 21:32:57 2021
> > New Revision: 24382
> >
> > Log:
> > Update qtwebengine to 5.15.3 from git.
> >
> > This is a lot bigger and slower to build.
> >
> > Downgrade the 'Caution's in qtwebengien and falkon to 'Warning's.
> > I am not yet suggesting we should deprecate those two packages,
> > but users should start to ask themselves whether the want to use
> > a package where the upstreams are happy to stick with python2
> > and have no interest in running on current glibc.
> >
[...]
> > + <sect2 role="kernel" id="qtwebengine-kernel">
> > + <title>Kernel Configuration</title>
> > +
> > + <para>
> > + Enable the following options in the kernel configuration and
> > recompile the
> > + kernel if necessary:
> > + </para>
> > +
> > +<!-- Spaces are significant in <screen> sections -->
> > +<screen><literal>General setup --->
> > + -*- Namespaces support --->
> > + [*] UTS namespace [CONFIG_UTS_NS]
> > + [*] TIME namespace [CONFIG_TIME_NS]
> > + [*] IPC namespace [CONFIG_IPC_NS]
> > + [ ] User namespace #CONFIG_USER_NS is not set
> > + [*] PID namespace [CONFIG_PID_NS]
> > + [*] Network namespace
> > [CONFIG_NET_NS]</literal></screen>
> > +
> > + <para>
> > + These are now the default options. Do <emphasis>NOT</emphasis>
> > enable
> > + User namespace (CONFIG_USER_NS), it <emphasis>will</emphasis> cause
> > + libQtWebengineCore to crash.
> > + </para>
> > +
> > + <indexterm zone="qtwebengine qtwebengine-kernel">
> > + <primary sortas="d-qtwebengine">qtwebengine</primary>
> > + </indexterm>
> > + </sect2>
> >
> >
> This is going to be a problem. UPower requires CONFIG_USER_NS to function
> properly.
>
Ouch. After adding '-config debug' to the qconf invocation (in
front of the '--') I was able to make a debug build (needs 25GB for
source and install). Trying to run falkon from gdb gave me a series
of backtraces (multiple threads).
[26147:26147:0318/162343.989885:FATAL:sandbox_linux.cc(555)] Check failed:
NamespaceSandbox::InNewPidNamespace().
bool SandboxLinux::EngageNamespaceSandboxInternal(bool from_zygote) {
CHECK(pre_initialized_);
CHECK(IsSingleThreaded())
<< "The process cannot have multiple threads when engaging the namespace "
"sandbox, because the thread engaging the sandbox cannot ensure that "
"other threads close all their open directories.";
if (from_zygote) {
// Check being in a new PID namespace created by the namespace sandbox and
// being the init process.
CHECK(NamespaceSandbox::InNewPidNamespace());
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
const pid_t pid = getpid();
CHECK_EQ(1, pid);
}
Note that on one of my machines where this works I do not have PID
namespaces enabled at the moment, but those settings above are all
the defaults and I obviously never saw any reason to enable that
when making oldconfig.
That failing code seems to have been called from
[26137:26137:0318/162346.234871:FATAL:zygote_host_impl_linux.cc(204)] Check
failed: ReceiveFixedMessage(fds[0], kZygoteHelloMessage,
sizeof(kZygoteHelloMessage), &real_pid).
But I was none the wiser about the rest of it, and after checking
that the chromium glibc-2.33 patch at Arch matched the qtwebengine
patch I tried turning off CONFIG_USER_NS just in case, and was
relieved whn falkon worked.
> I'll spend some time looking at this when i'm done with video editing work
> (Monday, which is also when I'll start on GNOME-40 and other tickets).
Sorry about that. But I'm surprised - the kernel help says (end of
lines trimmed for length)
CONFIG_USER_NS:
│
│ This allows containers, i.e. vservers, to use user namespaces
│ to provide different user info for different servers.
│
│ When user namespaces are enabled in the kernel it is
│ recommended that the MEMCG option also be enabled and that
│ user-space use the memory control groups to limit the amount
│ of memory a memory unprivileged users can use.
│
│ If unsure, say N.
ĸen
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