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From: Sergey Matyukevich <geomatsi@gmail.com>
To: linux-riscv@lists.infradead.org
Cc: Anup Patel <anup@brainfault.org>,
	Atish Patra <atishp@rivosinc.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Samuel Holland <samuel.holland@sifive.com>,
	Sergey Matyukevich <sergey.matyukevich@syntacore.com>
Subject: Re: [PATCH] riscv: prevent pt_regs corruption for secondary idle threads
Date: Mon, 13 May 2024 15:19:34 +0300	[thread overview]
Message-ID: <ZkIFVtHKRKE2Zm9n@curiosity> (raw)
In-Reply-To: <20240424221927.900612-1-geomatsi@gmail.com>

Hi all,

> From: Sergey Matyukevich <sergey.matyukevich@syntacore.com>
> 
> 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 c7cdd96eca29
> ("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 stores 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.
> 
> Fixes: 9a2451f18663 ("RISC-V: Avoid using per cpu array for ordered booting")
> Fixes: 2875fe056156 ("RISC-V: Add cpu_ops and modify default booting method")
> Signed-off-by: Sergey Matyukevich <sergey.matyukevich@syntacore.com>

Friendly ping about this fix. Any thoughts/comments ?

Regards,
Sergey

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  reply	other threads:[~2024-05-13 12:19 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-24 22:19 [PATCH] riscv: prevent pt_regs corruption for secondary idle threads Sergey Matyukevich
2024-05-13 12:19 ` Sergey Matyukevich [this message]
2024-05-22 16:33 ` Alexandre Ghiti

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