CVE-2024-26899

In the Linux kernel, the following vulnerability has been resolved: block:
fix deadlock between bd_link_disk_holder and partition scan ‘open_mutex’ of
gendisk is used to protect open/close block devices. But in
bd_link_disk_holder(), it is used to protect the creation of symlink
between holding disk and slave bdev, which introduces some issues. When
bd_link_disk_holder() is called, the driver is usually in the process of
initialization/modification and may suspend submitting io. At this time,
any io hold ‘open_mutex’, such as scanning partitions, can cause deadlocks.
For example, in raid: T1 T2 bdev_open_by_dev lock open_mutex [1] …
efi_partition … md_submit_bio md_ioctl mddev_syspend -> suspend all io
md_add_new_disk bind_rdev_to_array bd_link_disk_holder try lock open_mutex
[2] md_handle_request -> wait mddev_resume T1 scan partition, T2 add a new
device to raid. T1 waits for T2 to resume mddev, but T2 waits for
open_mutex held by T1. Deadlock occurs. Fix it by introducing a local mutex
‘blk_holder_mutex’ to replace ‘open_mutex’.