Fixing the glibc adobe flash incompatibility

drago01 drago01 at
Wed Nov 17 09:20:35 UTC 2010

On Wed, Nov 17, 2010 at 10:17 AM, nodata <lsof at> wrote:
> On 17/11/10 08:57, Hans de Goede wrote:
>> Hi all,
>> For those who do not know it yet, recent Fedora glibc updates include
>> an optimized memcpy (which gets used on some processors) which breaks the
>> 64 bit adobe flash plugin.
>> The problem has been analyzed and is known, as well as a fix for it, see:
>> The problem still exists however. The glibc developers say that this is
>> not a glibc bug, but a flash plugin bug. And technically they are 100%
>> correct, and the adobe flash plugin is a buggy .... (no surprise there).
>> To be specific the flash plugin is doing overlapping memcpy-s which is
>> clearly not how memcpy is supposed to be used. But the way the flash
>> plugin does overlapping memcpy's happens to work fine as long as one as
>> the c library does the memcpy-s in forward direction. And the new memcpy
>> implementation does the memcpy in backward direction.
>> The glibc developers being technically 100% correct is not helping our
>> end users in this case though. So we (The Fedora project) need to come up
>> with a solution to help our end users, many of whom want to use the adobe
>> flash plugin.
>> This solution could be reverting the problem causing glibc change, or
>> maybe changing it to do forward memcpy's while still using the new SSE
>> instructions, or something more specific to the flash plugin, as long
>> as it will automatically fix things with a yum upgrade without requiring
>> any further user intervention.
>> I would also like to point out that if this were to happen in Ubuntu
>> which we sometimes look at jealously for getting more attention / users
>> then us, the glibc change would likely be reverted immediately, as that
>> is the right thing to do from an end user pov.
>> I've filed a ticket for FESCo to look into this, as I believe this
>> makes us look really bad, and the glibc maintainers do not seem to be
>> willing to fix it without some sort of intervention:
>> Regards,
>> Hans
> Is someone talking to Adobe about this?

Yes, see

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