vulnerability
Red Hat: CVE-2022-50091: kernel: locking/csd_lock: Change csdlock_debug from early_param to __setup
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 7 | (AV:L/AC:M/Au:S/C:C/I:C/A:C) | Jun 18, 2025 | Jul 9, 2025 | Jul 21, 2025 |
Description
In the Linux kernel, the following vulnerability has been resolved:
locking/csd_lock: Change csdlock_debug from early_param to __setup
The csdlock_debug kernel-boot parameter is parsed by the
early_param() function csdlock_debug(). If set, csdlock_debug()
invokes static_branch_enable() to enable csd_lock_wait feature, which
triggers a panic on arm64 for kernels built with CONFIG_SPARSEMEM=y and
CONFIG_SPARSEMEM_VMEMMAP=n.
With CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section is called in
static_key_enable() and returns NULL, resulting in a NULL dereference
because mem_section is initialized only later in sparse_init().
This is also a problem for powerpc because early_param() functions
are invoked earlier than jump_label_init(), also resulting in
static_key_enable() failures. These failures cause the warning "static
key 'xxx' used before call to jump_label_init()".
Thus, early_param is too early for csd_lock_wait to run
static_branch_enable(), so changes it to __setup to fix these.
Solution
References
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