riscv: prevent pt_regs corruption for secondary idle threads
3Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackepss 0.2%
exploitation probability
0.2%top 88% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
riscv: prevent pt_regs corruption for secondary idle threads
Top of the kernel thread stack should be reserved for pt_regs. However
this is not the case for the idle threads of the secondary boot harts.
Their stacks overlap with their pt_regs, so both may get corrupted.
Similar issue has been fixed for the primary hart, see c7cdd96eca28
("riscv: prevent stack corruption by reserving task_pt_regs(p) early").
However that fix was not propagated to the secondary harts. The problem
has been noticed in some CPU hotplug tests with V enabled. The function
smp_callin stored several registers on stack, corrupting top of pt_regs
structure including status field. As a result, kernel attempted to save
or restore inexistent V context.
Affected products
Linux · Linux