544904 - Random behaviour with flash plugin and focus when activating the CPU hiperthreading

Status: RESOLVED INCOMPLETE

(Core Graveyard :: Plug-ins, defect)

Description

[Enrique]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2) Gecko/20100125 Mandriva Linux/1.9.2-2mdv2010.1 (2010.1) Firefox/3.6
Build Identifier: 20090624012820

I'm observing a weird behaviour with the focus when embedding a flash plugin into the web page. Sometimes the focus goes to the browser, someothers it goes to the plugin.
***The bug is related to the hiperthreading since once I disable it in the BIOS the problem disapears.***
 I'm using an Intel Atom for testing. /proc/cpuinfo returns:

  1 processor   : 0
  2 vendor_id   : GenuineIntel
  3 cpu family  : 6
  4 model       : 28
  5 model name  : Intel(R) Atom(TM) CPU  230   @ 1.60GHz
  6 stepping    : 2
  7 cpu MHz     : 1599.713
  8 cache size  : 512 KB
  9 physical id : 0
 10 siblings    : 1
 11 core id     : 0
 12 cpu cores   : 1
 13 apicid      : 0
 14 initial apicid  : 0
 15 fdiv_bug    : no
 16 hlt_bug     : no
 17 f00f_bug    : no
 18 coma_bug    : no
 19 fpu     : yes
 20 fpu_exception   : yes
 21 cpuid level : 10
 22 wp      : yes
 23 flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc up arch_perfmon pebs bts pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm lahf_lm
 24 bogomips    : 3199.42
 25 clflush size    : 64
 26 power management:

Browsing on the Wikipedia it looks hiperthreading share the same internal cache, just the Architectural state (http://en.wikipedia.org/wiki/Architectural_state) is different for each thread, so I guess it must be an int or long variable used as a lock or counter or something like that to be blamed for this bug. (an "small piece of data" that the compiler is able to put into a CPU register that has not been properly protected for simultaneaus thread access).

Reproducible: Sometimes

Steps to Reproduce:
1.Activate hiperthreading in BIOS.
2.Load an html page with some flash videos and put focus into an input box.

Actual Results:  
Sometimes I can start typing text into the input box. Some others I  have to manually use the mouse to put the focus the into the input box.

Expected Results:  
Focus have to go always to the input box, not to the flash plugin.

http://en.wikipedia.org/wiki/Hyper-Threading

Comment 1

[Enrique]

I'm using matchbox-window-manager. I'm not sure who is to blame, Firefox, the wm or maybe the Xorg server. I put that same bug repport in the openhand.com bugzilla system:

http://bugzilla.openedhand.com/show_bug.cgi?id=1984

Comment 2

[Kevin Brosnan]

Works for me - Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.3a5pre) Gecko/20100602 Minefield/3.7a5pre - Flash 10.0 r45 x64.

Tried several Youtube videos as well as some Vimeo pages. Could not reproduce. Is there a specific page that this happens on? Is the text box inside the flash object or elsewhere on the page?

Comment 3

[Benjamin Smedberg]

Resolving old bugs which are likely not relevant any more, since NPAPI plugins are deprecated.