Commit ce7b1756 authored Nov 22, 2012 by Lorenzo Pieralisi Committed by Russell King Nov 23, 2012

ARM: 7585/1: kernel: fix nr_cpu_ids check in DT logical map init



If a kernel is configured with a DT containing more /cpu nodes than
nr_cpu_ids, the number of cpus must be capped in the DT parsing
code. Current code carries out the check, but fails to cap the
value and the check is executed after the cpu logical index is used,
which can lead to memory corruption due to index overflow.

This patch refactors the check against nr_cpu_ids and move it before
any computed index is used in the parsing code.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent c7cc504b

arch/arm/kernel/devtree.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -139,12 +139,16 @@ void __init arm_dt_init_cpu_maps(void)
		i = cpuidx++;
		}

		tmp_map[i] = hwid;

		if (cpuidx > nr_cpu_ids)
		if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
		"max cores %u, capping them\n",
		cpuidx, nr_cpu_ids)) {
		cpuidx = nr_cpu_ids;
		break;
		}

		tmp_map[i] = hwid;
		}

		if (WARN(!bootcpu_valid, "DT missing boot CPU MPIDR[23:0], "
		"fall back to default cpu_logical_map\n"))
		return;