Fixing the glibc adobe flash incompatibility

nodata lsof at
Wed Nov 17 10:36:33 UTC 2010

On 17/11/10 10:20, drago01 wrote:
> 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

Adobe benefits from Flash in Linux. So it seems sensible to:

1. Get Adobe to commit to a fix soon WITH A $DATE
2. Agree to patch the change until $DATE
3. Adobe updates Flash, we revert the patch, everyone is happy

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