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Commit 2b46b567 authored by Michael Neuling's avatar Michael Neuling Committed by Paul Mackerras
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[POWERPC] Fix possible division by zero in scaled time accounting 



If we get no user time and no system time allocated since the last
account_system_vtime, the system to user time ratio estimate can end
up dividing by zero.

This was causing a problem noticed by Balbir Singh.

Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent c443acab

arch/powerpc/kernel/time.c

+3 −2
Original line number Diff line number Diff line
@@ -241,6 +241,7 @@ void account_system_vtime(struct task_struct *tsk) 
		/* deltascaled includes both user and system time.

		 * Hence scale it based on the purr ratio to estimate

		 * the system time */

		if (get_paca()->user_time)

			deltascaled = deltascaled * get_paca()->system_time /

			     (get_paca()->system_time + get_paca()->user_time);

		delta += get_paca()->system_time;