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From: Thomas Gleixner <tglx@linutronix.de>
To: Anup Patel <apatel@ventanamicro.com>, Palmer Dabbelt
 <palmer@dabbelt.com>, Paul Walmsley <paul.walmsley@sifive.com>, Rob
 Herring <robh+dt@kernel.org>, Krzysztof Kozlowski
 <krzysztof.kozlowski+dt@linaro.org>, Frank Rowand
 <frowand.list@gmail.com>, Conor Dooley <conor+dt@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>, =?utf-8?B?QmrDtnJuIFTDtnBlbA==?=
 <bjorn@kernel.org>, Atish
 Patra <atishp@atishpatra.org>, Andrew Jones <ajones@ventanamicro.com>,
 Sunil V L <sunilvl@ventanamicro.com>, Saravana Kannan
 <saravanak@google.com>, Anup Patel <anup@brainfault.org>,
 linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
 linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Anup Patel
 <apatel@ventanamicro.com>
Subject: Re: [PATCH v13 02/13] irqchip/sifive-plic: Improve locking safety
 by using irqsave/irqrestore
In-Reply-To: <20240220060718.823229-3-apatel@ventanamicro.com>
References: <20240220060718.823229-1-apatel@ventanamicro.com>
 <20240220060718.823229-3-apatel@ventanamicro.com>
Date: Tue, 20 Feb 2024 11:11:19 +0100
Message-ID: <87frxnigxk.ffs@tglx>
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On Tue, Feb 20 2024 at 11:37, Anup Patel wrote:
> Now that PLIC driver is probed as a regular platform driver, the lock
> dependency validator complains about the safety of handler->enable_lock
> usage:
>
> [    0.956775]  Possible interrupt unsafe locking scenario:
>
> [    0.956998]        CPU0                    CPU1
> [    0.957247]        ----                    ----
> [    0.957439]   lock(&handler->enable_lock);
> [    0.957607]                                local_irq_disable();
> [    0.957793]                                lock(&irq_desc_lock_class);
> [    0.958021]                                lock(&handler->enable_lock);
> [    0.958246]   <Interrupt>
> [    0.958342]     lock(&irq_desc_lock_class);
> [    0.958501]
>                 *** DEADLOCK ***
>
> To address above, let's use raw_spin_lock_irqsave/unlock_irqrestore()
> instead of raw_spin_lock/unlock().

s/let's//