From: "Randy.Dunlap" <rddunlap@osdl.org> When setting the 'cpu_isolated_map' mask, check that the user input value is valid (in range 0 .. NR_CPUS - 1). Also fix up kernel-parameters.txt for this parameter. Signed-off-by: Randy Dunlap <rddunlap@osdl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> --- 25-akpm/Documentation/kernel-parameters.txt | 4 +++- 25-akpm/kernel/sched.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff -puN Documentation/kernel-parameters.txt~cpumask-range-check-before-using-value Documentation/kernel-parameters.txt --- 25/Documentation/kernel-parameters.txt~cpumask-range-check-before-using-value Fri Dec 3 13:44:13 2004 +++ 25-akpm/Documentation/kernel-parameters.txt Fri Dec 3 13:44:13 2004 @@ -583,11 +583,13 @@ running once the system is up. Format: <RDP>, <reset>, <pci_scan>, <verbosity> isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. - Format: <cpu number>, ..., <cpu number> + Format: <cpu number>,...,<cpu number> This option can be used to specify one or more CPUs to isolate from the general SMP balancing and scheduling algorithms. The only way to move a process onto or off an "isolated" CPU is via the CPU affinity syscalls. + <cpu number> begins at 0 and the maximum value is + "number of CPUs in system - 1". This option is the preferred way to isolate CPUs. The alternative - manually setting the CPU mask of all tasks diff -puN kernel/sched.c~cpumask-range-check-before-using-value kernel/sched.c --- 25/kernel/sched.c~cpumask-range-check-before-using-value Fri Dec 3 13:44:13 2004 +++ 25-akpm/kernel/sched.c Fri Dec 3 13:44:13 2004 @@ -36,6 +36,7 @@ #include <linux/blkdev.h> #include <linux/delay.h> #include <linux/smp.h> +#include <linux/threads.h> #include <linux/timer.h> #include <linux/rcupdate.h> #include <linux/cpu.h> @@ -4169,7 +4170,8 @@ static int __init isolated_cpu_setup(cha str = get_options(str, ARRAY_SIZE(ints), ints); cpus_clear(cpu_isolated_map); for (i = 1; i <= ints[0]; i++) - cpu_set(ints[i], cpu_isolated_map); + if (ints[i] < NR_CPUS) + cpu_set(ints[i], cpu_isolated_map); return 1; } _