Re: [PATCH] acpi/arm64: Adjust error handling procedure in gtdt_parse_timer_block()

[Hanjun Guo <guohanjun@huawei.com>]

On 2024/8/27 18:12, Aleksandr Mishin wrote:
> In case of error in gtdt_parse_timer_block() invalid 'gtdt_frame'
> will be used in 'do {} while (i-- >= 0 && gtdt_frame--);' statement block
> because do{} block will be executed even if 'i == 0'.
> 
> Adjust error handling procedure by replacing 'i-- >= 0' with 'i-- > 0'.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: a712c3ed9b8a ("acpi/arm64: Add memory-mapped timer support in GTDT driver")
> Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
> ---
>   drivers/acpi/arm64/gtdt.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
> index c0e77c1c8e09..eb6c2d360387 100644
> --- a/drivers/acpi/arm64/gtdt.c
> +++ b/drivers/acpi/arm64/gtdt.c
> @@ -283,7 +283,7 @@ static int __init gtdt_parse_timer_block(struct acpi_gtdt_timer_block *block,
>   		if (frame->virt_irq > 0)
>   			acpi_unregister_gsi(gtdt_frame->virtual_timer_interrupt);
>   		frame->virt_irq = 0;
> -	} while (i-- >= 0 && gtdt_frame--);
> +	} while (i-- > 0 && gtdt_frame--);

Good catch,

Acked-by: Hanjun Guo <guohanjun@huawei.com>

It's a fix in the error path, so I think it's OK for next release cycle.

Thanks
Hanjun