Commit a6e4491c authored by Prarit Bhargava's avatar Prarit Bhargava Committed by Ingo Molnar
Browse files

sched/isolcpus: Output warning when the 'isolcpus=' kernel parameter is invalid

The isolcpus= kernel boot parameter restricts userspace from scheduling on
the specified CPUs.

If a CPU is specified that is outside the range of 0 to nr_cpu_ids,
cpulist_parse() will return -ERANGE, return an empty cpulist, and
fail silently.

This patch adds an error message to isolated_cpu_setup() to indicate to
the user that something has gone awry, and returns 0 on error.
Signed-off-by: default avatarPrarit Bhargava <>
Cc: Linus Torvalds <>
Cc: Peter Zijlstra <>
Cc: Thomas Gleixner <>

[ Twiddled some details. ]
Signed-off-by: default avatarIngo Molnar <>
parent b37a05c0
......@@ -6173,11 +6173,16 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
int ret;
cpulist_parse(str, cpu_isolated_map);
ret = cpulist_parse(str, cpu_isolated_map);
if (ret) {
pr_err("sched: Error, all isolcpus= values must be between 0 and %d\n", nr_cpu_ids);
return 0;
return 1;
__setup("isolcpus=", isolated_cpu_setup);
struct s_data {
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