On 8/16/19 4:54 AM, Ming Lei wrote:
> It is reported that sysfs buffer overflow can be triggered in case
> of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in
> blk_mq_hw_sysfs_cpus_show().
>
> So use cpumap_print_to_pagebuf() to print the info and fix the potential
> buffer overflow issue.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Mark Ray <mark.ray@xxxxxxx>
> Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
> Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load")
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> block/blk-mq-sysfs.c | 15 +--------------
> 1 file changed, 1 insertion(+), 14 deletions(-)
>
> diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
> index d6e1a9bd7131..4d0d32377ba3 100644
> --- a/block/blk-mq-sysfs.c
> +++ b/block/blk-mq-sysfs.c
> @@ -166,20 +166,7 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
>
> static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
> {
> - unsigned int i, first = 1;
> - ssize_t ret = 0;
> -
> - for_each_cpu(i, hctx->cpumask) {
> - if (first)
> - ret += sprintf(ret + page, "%u", i);
> - else
> - ret += sprintf(ret + page, ", %u", i);
> -
> - first = 0;
> - }
> -
> - ret += sprintf(ret + page, "\n");
> - return ret;
> + return cpumap_print_to_pagebuf(true, page, hctx->cpumask);
> }
>
> static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
And maybe you should send a update to the kABI documentation to keep
Greg KH happy :-)
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)
