On Wed, Nov 30, 2016 at 03:32:22PM -0800, Tadeusz Struk wrote:
> Irq balancer scans the isolcpus and nohz_full kernel masks and adds the
> corresponding CPUs to the banned_cpus mask. This works fine for valid masks,
> but not for the default, emtpy masks. In this case when they read from the
> sysfs they return empty strings, "\n" or "0x0, \n":
>
> # xxd /sys/devices/system/cpu/nohz_full
> 0000000: 000a
> # xxd /sys/devices/system/cpu/isolated
> 0000000: 0a
>
> Irqbalancer reads them and blindly passes these values to the
> __bitmap_parselist() function, which expects ASCII string format.
> For this input the implementation always set the first bit indicating CPU 0.
>
> Steps to Reproduce:
> 1. Make sure /sys/devices/system/cpu/nohz_full and
> /sys/devices/system/cpu/isolated are empty
> 2. run $ /usr/sbin/irqbalance -d --oneshot | grep Isolated
>
> Actual results:
> Isolated CPUs: 00000001
>
> Expected results:
> Isolated CPUs: 00000000
>
> Signed-off-by: Tadeusz Struk <tadeusz.struk at intel.com>
> ---
> cputree.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/cputree.c b/cputree.c
> index a188ead..8762b64 100644
> --- a/cputree.c
> +++ b/cputree.c
> @@ -84,7 +84,8 @@ static void setup_banned_cpus(void)
> file = fopen("/sys/devices/system/cpu/isolated", "r");
> if (file) {
> if (getline(&line, &size, file) > 0) {
> - cpulist_parse(line, size, isolated_cpus);
> + if (strlen(line) && line[0] != '\n')
> + cpulist_parse(line, strlen(line), isolated_cpus);
> free(line);
> line = NULL;
> size = 0;
> @@ -95,7 +96,8 @@ static void setup_banned_cpus(void)
> file = fopen("/sys/devices/system/cpu/nohz_full", "r");
> if (file) {
> if (getline(&line, &size, file) > 0) {
> - cpulist_parse(line, size, nohz_full);
> + if (strlen(line) && line[0] != '\n')
> + cpulist_parse(line, strlen(line), nohz_full);
> free(line);
> line = NULL;
> size = 0;
>
>
> _______________________________________________
> irqbalance mailing list
> irqbalance at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/irqbalance
>
Applied, thanks!
Neil
