"tvec_bases too large for per-cpu data" commit broke early_serial_setup()

Eugene Surovegin ebs at ebshome.net
Sun Apr 2 06:53:36 EST 2006


Hi!

Commit 
a4a6198b80cf82eb8160603c98da218d1bd5e104 
"[PATCH] tvec_bases too large for per-cpu data"

broke early_serial_setup() and maybe other code which uses 
init_timer() before init_timers_cpu() is called.

This commit introduced run-time initialization dependence which never 
existed before, namely, tvec_bases was always valid before this 
change, but now it's a pointer which should be initialized prior to 
use of any timer function.

If init_timer() is called before such initialization (in my case this 
happens when PPC440GX board support code calls early_serial_setup to 
register UARTs, serial8250_isa_init_ports() calls init_timer()), 
"base" field in the timer_list struct is set to NULL.

When later mod_timer() is called for such timer it hangs in 
lock_timer_base().

Rolling back this commit fixes the problem, although, this is 
obviously not a proper fix.

I don't a fix I like, so I'll leave it to people more familiar with 
this matter :)

-- 
Eugene






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