[syslinux] Boot prompt ignored

[Alex F]

On Sat, May 07, 2016 at 09:56:59PM +0300, Ady via Syslinux wrote:
> On Sun, May 01, 2016 at 11:58:41AM +0200, Alexander Freudenberg via Syslinux wrote:
> > Using a boot prompt without a menu makes Syslinux 6.03-6 booting the
> > default label only, ignoring the label that was entered. Auto completion
> > of the defined labels works, though. Can anyone confirm this?
> >
>
> I compiled binaries from the (hopefully, temporarily) "revert-9acbffd"
> branch from GeneC. The building environment is using old dependencies
> (i.e. not recent versions).
>
> With the resulting binaries, the aforementioned strange behavior was
> _not_ replicated -- _please_, do not just take this as valid / true;
> this same test _must_ be performed by others so to corroborate this
> result.
>
> But, using binaries from Fedora, 6.03-6.fc24, the problematic behavior
> _can_ be replicated.
>
> It has also been replicated by at least one additional user of
> ArchLinux, by using binaries from 6.03-6 (which is probably the package
> that was used by the original reporter).
>
> Additionally, at least one Debian Sid user is reporting the same
> unwanted behavior with 6.03+dfsg-12. Although the problem is not seen
> with  6.03+dfsg-11, I would not suggest that Debian should revert back.
> but rather that (additional) patches for gcc5+ compatibility should be
> also applied to Debian's packages.
>
> The abnormal behavior cannot be replicated with official 6.03 pre-built
> binaries downloaded from kernel.org.
>
> I have not bothered to test with 6.04-pre1 (as I would consider its
> binaries a waste of time, after they have failed me already in other
> tests).
>
> I should add that typing-in either labels or any other command, the
> result is the same: only / always the default command (label) is
> executed when pressing ENTER. To be accurate, I have not actually
> tested whether it is really the DEFAULT command, or the first LABEL,
> that is being executed.
>
> So, this seems to be some environmental / building issue -- again,
> please do not take this statement as valid / true unless these tests
> are replicated by others.
>
> Considering that most Linux distributions that are already using some
> package based on Syslinux 6.03 are also using relatively-updated
> versions of its dependencies (e.g. gcc5+, binutils 2.23+ and so on), I
> am wondering whether some of the pending problems related to makefiles
> and/or ld files could be the source of this unwanted behavior.
>
> For instance, "HIDDEN was added to ld in binutils version 2.23", and
> the current Syslinux source code (both, 6.03 and current git master
> head) is not using the necessary code to cope with this "HIDDEN".
> Perhaps it is time to add some kind of conditional code in Syslinux's
> "*.ld" files , depending on the version of binutils, so binaries could
> be functional in both cases (binutils prior and/or post/equal to
> version 2.23).
>
> Of course this is just an example, and it might not be the culprit of
> this problem. Yet, the basic concept might be relevant for whatever
> might be generating this issue.
>
> Another possible issue that might come to mind: building with/without
> "CFLAGS += -fno-PIE" or something of that sort.
>
> These are wild uneducated guesses; so much so that calling it a "guess"
> might already be too much. I hope knowledgeable developers will find a
> solution.
>
> Regards,
> Ady.
>

Turns out, the undesired behaviour must be somewhat specific to the
build in Arch Linux' repository.

After building Syslinux from the official source, it boots any label
entered during boot prompt correctly. (I have not tested removing the
DEFAULT statement, though)


Thank you for your help - Alex