Hello.
Suleiman Souhlal wrote:
It is possible for the timer expiry function to run even though the
request has already been handled: ide_timer_expiry() only checks that
the handler is not NULL, but it is possible that we have handled a
request (thus clearing the handler) and then started a new request
(thus starting the timer again, and setting a handler).
A simple way to exhibit this is to set the DMA timeout to 1 jiffy and
run dd: The kernel will panic after a few minutes because
ide_timer_expiry() tries to add a timer when it's already active.
To fix this, we simply add a request generation count that gets
incremented at every interrupt, and check in ide_timer_expiry() that
we have not already handled a new interrupt before running the expiry
function.
Couldn't this be addressed by simply changing add_timer() to mod_timer()?
MBR, Sergei
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