CVE Published: 21/05/2024 |
CVE Updated: 04/11/2024 |
CVE Year: 2021 Source: Linux |
Vendor: Linux |
Product: Linux Status : PUBLISHED
CVE-2021-47412 Description
In the Linux kernel, the following vulnerability has been resolved:
block: don\'t call rq_qos_ops->done_bio if the bio isn\'t tracked
rq_qos framework is only applied on request based driver, so:
1) rq_qos_done_bio() needn\'t to be called for bio based driver
2) rq_qos_done_bio() needn\'t to be called for bio which isn\'t tracked,
such as bios ended from error handling code.
Especially in bio_endio():
1) request queue is referred via bio->bi_bdev->bd_disk->queue, which
may be gone since request queue refcount may not be held in above two
cases
2) q->rq_qos may be freed in blk_cleanup_queue() when calling into
__rq_qos_done_bio()
Fix the potential kernel panic by not calling rq_qos_ops->done_bio if
the bio isn\'t tracked. This way is safe because both ioc_rqos_done_bio()
and blkcg_iolatency_done_bio() are nop if the bio isn\'t tracked.