8.2.2 Beta-1 test request

Daniel Drake dsd at laptop.org
Mon Dec 7 03:45:14 EST 2009


On Mon, 2009-12-07 at 01:25 -0500, Chris Ball wrote:
> Hi,
> 
>    > Curious: is there a trac bug # for this?  I think stock Ubuntu
>    > hardy might have the same problem (or a related one)? 
> 
> I think this bug is a pet peeve of dsd's, so he might reply with more
> details, but the sources I can find quickly are:

Doing VT_ACTIVATE then VT_WAITACTIVE is susceptible to a race, if
another process does VT_ACTIVATE to a different terminal inbetween those
2 calls then you're screwed.

For example think of these 2 processes running at the same time: chvt 1,
chvt 2

proc #1			proc #2

VT_ACTIVATE 1
			VT_ACTIVATE 2
VT_WAITACTIVE 1
			VT_WAITACTIVE 2



proc #2 will finish and you'll be on vt2, but proc #1 will wait and wait
and wait.

Daniel





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