linux-kernel - Re: [PATCH] dmaengine: idxd: Remove unnecessary synchronize_irq() before free

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 13 May 2022 07:30:35 -0700
From:   Dave Jiang <dave.jiang@...el.com>
To:     cgel.zte@...il.com
Cc:     vkoul@...nel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, Minghao Chi <chi.minghao@....com.cn>,
        Zeal Robot <zealci@....com.cn>
Subject: Re: [PATCH] dmaengine: idxd: Remove unnecessary synchronize_irq()
 before free_irq()


On 5/13/2022 1:16 AM, cgel.zte@...il.com wrote:
> From: Minghao Chi <chi.minghao@....com.cn>
>
> Calling synchronize_irq() right before free_irq() is quite useless. On one
> hand the IRQ can easily fire again before free_irq() is entered, on the
> other hand free_irq() itself calls synchronize_irq() internally (in a race
> condition free way) before any state associated with the IRQ is freed.

Fair enough. Thanks.

Acked-by: Dave Jiang <dave.jiang@...el.com>


>
> Reported-by: Zeal Robot <zealci@....com.cn>
> Signed-off-by: Minghao Chi <chi.minghao@....com.cn>
> ---
>   drivers/dma/idxd/device.c | 1 -
>   1 file changed, 1 deletion(-)
>
> diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
> index 5363fb9218f2..9dd8e6bb21e6 100644
> --- a/drivers/dma/idxd/device.c
> +++ b/drivers/dma/idxd/device.c
> @@ -1179,7 +1179,6 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
>   	struct idxd_device *idxd = wq->idxd;
>   	struct idxd_irq_entry *ie = &wq->ie;
>   
> -	synchronize_irq(ie->vector);
>   	free_irq(ie->vector, ie);
>   	idxd_flush_pending_descs(ie);
>   	if (idxd->request_int_handles)
> --
> 2.25.1
>
>