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().
This info isn't useful, given users may retrieve the CPU list from sw queue entries under same kobject dir, so far not see any active users.
So remove the entry as suggested by Greg.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Cc: Greg KH gregkh@linuxfoundation.org Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com --- block/blk-mq-sysfs.c | 23 ----------------------- 1 file changed, 23 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e0b97c22726c 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,24 +164,6 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); }
-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; -} - static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = { .attr = {.name = "nr_tags", .mode = 0444 }, .show = blk_mq_hw_sysfs_nr_tags_show, @@ -190,15 +172,10 @@ static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = { .attr = {.name = "nr_reserved_tags", .mode = 0444 }, .show = blk_mq_hw_sysfs_nr_reserved_tags_show, }; -static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = { - .attr = {.name = "cpu_list", .mode = 0444 }, - .show = blk_mq_hw_sysfs_cpus_show, -};
static struct attribute *default_hw_ctx_attrs[] = { &blk_mq_hw_sysfs_nr_tags.attr, &blk_mq_hw_sysfs_nr_reserved_tags.attr, - &blk_mq_hw_sysfs_cpus.attr, NULL, }; ATTRIBUTE_GROUPS(default_hw_ctx);