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: [email protected] > Cc: Mark Ray <[email protected]> > Cc: Greg KH <[email protected]> > Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") > Signed-off-by: Ming Lei <[email protected]> > --- > 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 <[email protected]>
And maybe you should send a update to the kABI documentation to keep Greg KH happy :-) Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg)
