Commit 4f8048ee authored Oct 29, 2009 by Heiko Carstens Committed by Martin Schwidefsky Oct 29, 2009

[S390] smp: fix prefix handling of offlined cpus



Offlined cpus still have valid prefix register contents. Dumpers
will store the register contents of a cpu to the location where its
prefix register points to.
For offlined cpus the area (lowcore) has been freed and the dumper
would write the uninteresting contents of the offline cpu to a memory
location which might be in use by some other component and destroy
valueable information.
To fix this set the prefix register of offline cpus to absolute
address zero again. This prevents the current dumpers to write to
random memory locations.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

parent 8ca45667

arch/s390/kernel/smp.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -638,6 +638,8 @@ void __cpu_die(unsigned int cpu)
		/* Wait until target cpu is down */
		while (!cpu_stopped(cpu))
		cpu_relax();
		while (signal_processor_p(0, cpu, sigp_set_prefix) == sigp_busy)
		udelay(10);
		smp_free_lowcore(cpu);
		pr_info("Processor %d stopped\n", cpu);
		}

Admin message