What happened
In the Linux kernel, the following vulnerability has been resolved: blk-mq: fix tags leak when shrink nr_hw_queues Although we don't need to realloc set->tags[] when shrink nr_hw_queues, we need to free them. Or these tags will be leaked. How to reproduce: 1. mount -t configfs configfs /mnt 2. modprobe null_blk nr_devices=0 submit_queues=8 3. mkdir /mnt/nullb/nullb0 4. echo 1 > /mnt/nullb/nullb0/power 5. echo 4 > /mnt/nullb/nullb0/submit_queues 6. rmdir /mnt/nullb/nullb0 In step 4, will alloc 9 tags (8 submit queues and 1 poll queue), then in step 5, new_nr_hw_queues = 5 (4 submit queues and 1 poll queue). At last in step 6, only these 5 tags are freed, the other 4 tags leaked.
Affected versions
Linux: a846a8e6c9a5949582c5a6a8bbc83a7d27fd891e through before 26d495f0f64d8cd4fcd29206ee5c653ee0e0cbcd (git); a846a8e6c9a5949582c5a6a8bbc83a7d27fd891e through before c0ef7493e68b8896806a2f598fcffbaa97333405 (git); a846a8e6c9a5949582c5a6a8bbc83a7d27fd891e through before e1dd7bc93029024af5688253b0c05181d6e01f8e (git); 5.16 Fixed: See vendor advisory.
Why it matters
Review the vendor advisory and exposure of the affected product to determine operational impact.
Detection & mitigation
- Apply vendor-provided updates or mitigations.
- Review affected product exposure and access logs.
Public PoC references
No public PoC reference has passed the current publication threshold.