Re: [PATCH v2] riscv: prevent pt_regs corruption for secondary idle threads

From: patchwork-bot+linux-riscv
Date: Thu May 30 2024 - 17:13:32 EST


Hello:

This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <palmer@xxxxxxxxxxxx>:

On Thu, 23 May 2024 11:43:23 +0300 you wrote:
> From: Sergey Matyukevich <sergey.matyukevich@xxxxxxxxxxxxx>
>
> 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.
>
> [...]

Here is the summary with links:
- [v2] riscv: prevent pt_regs corruption for secondary idle threads
https://git.kernel.org/riscv/c/a638b0461b58

You are awesome, thank you!
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