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From: Baoquan He <bhe@redhat.com>
To: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Eric Biederman <ebiederm@xmission.com>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	Michael Holzheu <holzheu@linux.vnet.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 3/6] kexec: clear crashk_res if all its memory has been released
Date: Wed, 31 May 2023 08:33:34 +0800	[thread overview]
Message-ID: <ZHaVuJrlYhIlpkFE@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20230527123439.772-4-thunder.leizhen@huawei.com>

On 05/27/23 at 08:34pm, Zhen Lei wrote:
> If the resource of crashk_res has been released, it is better to clear
> crashk_res.start and crashk_res.end. Because 'end = start - 1' is not
> reasonable, and in some places the test is based on crashk_res.end, not
> resource_size(&crashk_res).

This looks reasonable, at least I haven't think of any risk it could
bring. Thanks.

Acked-by: Baoquan He <bhe@redhat.com>

> 
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
>  kernel/kexec_core.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index d1ab139dd49035e..bcc86a250ab3bf9 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -1137,15 +1137,18 @@ int crash_shrink_memory(unsigned long new_size)
>  	end = start + new_size;
>  	crash_free_reserved_phys_range(end, crashk_res.end);
>  
> -	if (start == end)
> -		release_resource(&crashk_res);
> -
>  	ram_res->start = end;
>  	ram_res->end = crashk_res.end;
>  	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
>  	ram_res->name = "System RAM";
>  
> -	crashk_res.end = end - 1;
> +	if (start == end) {
> +		release_resource(&crashk_res);
> +		crashk_res.start = 0;
> +		crashk_res.end = 0;
> +	} else {
> +		crashk_res.end = end - 1;
> +	}
>  
>  	insert_resource(&iomem_resource, ram_res);
>  
> -- 
> 2.25.1
> 


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WARNING: multiple messages have this Message-ID (diff)
From: Baoquan He <bhe@redhat.com>
To: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Eric Biederman <ebiederm@xmission.com>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	Michael Holzheu <holzheu@linux.vnet.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 3/6] kexec: clear crashk_res if all its memory has been released
Date: Wed, 31 May 2023 08:33:34 +0800	[thread overview]
Message-ID: <ZHaVuJrlYhIlpkFE@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20230527123439.772-4-thunder.leizhen@huawei.com>

On 05/27/23 at 08:34pm, Zhen Lei wrote:
> If the resource of crashk_res has been released, it is better to clear
> crashk_res.start and crashk_res.end. Because 'end = start - 1' is not
> reasonable, and in some places the test is based on crashk_res.end, not
> resource_size(&crashk_res).

This looks reasonable, at least I haven't think of any risk it could
bring. Thanks.

Acked-by: Baoquan He <bhe@redhat.com>

> 
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
>  kernel/kexec_core.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index d1ab139dd49035e..bcc86a250ab3bf9 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -1137,15 +1137,18 @@ int crash_shrink_memory(unsigned long new_size)
>  	end = start + new_size;
>  	crash_free_reserved_phys_range(end, crashk_res.end);
>  
> -	if (start == end)
> -		release_resource(&crashk_res);
> -
>  	ram_res->start = end;
>  	ram_res->end = crashk_res.end;
>  	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
>  	ram_res->name = "System RAM";
>  
> -	crashk_res.end = end - 1;
> +	if (start == end) {
> +		release_resource(&crashk_res);
> +		crashk_res.start = 0;
> +		crashk_res.end = 0;
> +	} else {
> +		crashk_res.end = end - 1;
> +	}
>  
>  	insert_resource(&iomem_resource, ram_res);
>  
> -- 
> 2.25.1
> 


  reply	other threads:[~2023-05-31  0:33 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-27 12:34 [PATCH 0/6] kexec: enable kexec_crash_size to support two crash kernel regions Zhen Lei
2023-05-27 12:34 ` Zhen Lei
2023-05-27 12:34 ` [PATCH 1/6] kexec: fix a memory leak in crash_shrink_memory() Zhen Lei
2023-05-27 12:34   ` Zhen Lei
2023-05-31  0:13   ` Baoquan He
2023-05-31  0:13     ` Baoquan He
2023-05-31  1:16     ` Leizhen (ThunderTown)
2023-05-31  1:16       ` Leizhen (ThunderTown)
2023-05-31  7:31       ` Baoquan He
2023-05-31  7:31         ` Baoquan He
2023-05-27 12:34 ` [PATCH 2/6] kexec: delete a useless check " Zhen Lei
2023-05-27 12:34   ` Zhen Lei
2023-05-31  0:17   ` Baoquan He
2023-05-31  0:17     ` Baoquan He
2023-05-31  2:19     ` Leizhen (ThunderTown)
2023-05-31  2:19       ` Leizhen (ThunderTown)
2023-05-31  7:41       ` Baoquan He
2023-05-31  7:41         ` Baoquan He
2023-05-31  8:26         ` Leizhen (ThunderTown)
2023-05-31  8:26           ` Leizhen (ThunderTown)
2023-05-27 12:34 ` [PATCH 3/6] kexec: clear crashk_res if all its memory has been released Zhen Lei
2023-05-27 12:34   ` Zhen Lei
2023-05-31  0:33   ` Baoquan He [this message]
2023-05-31  0:33     ` Baoquan He
2023-05-27 12:34 ` [PATCH 4/6] kexec: improve the readability of crash_shrink_memory() Zhen Lei
2023-05-27 12:34   ` Zhen Lei
2023-05-31  7:48   ` Baoquan He
2023-05-31  7:48     ` Baoquan He
2023-05-27 12:34 ` [PATCH 5/6] kexec: add helper __crash_shrink_memory() Zhen Lei
2023-05-27 12:34   ` Zhen Lei
2023-05-28  0:08   ` kernel test robot
2023-05-28  0:08     ` kernel test robot
2023-05-29  0:37     ` Leizhen (ThunderTown)
2023-05-29  0:37       ` Leizhen (ThunderTown)
2023-05-28  1:44   ` kernel test robot
2023-05-28  1:44     ` kernel test robot
2023-05-28  6:26   ` kernel test robot
2023-05-28  6:26     ` kernel test robot
2023-05-31  7:50   ` Baoquan He
2023-05-31  7:50     ` Baoquan He
2023-05-27 12:34 ` [PATCH 6/6] kexec: enable kexec_crash_size to support two crash kernel regions Zhen Lei
2023-05-27 12:34   ` Zhen Lei
2023-05-31  9:53   ` Baoquan He
2023-05-31  9:53     ` Baoquan He
2023-05-31 14:25     ` Leizhen (ThunderTown)
2023-05-31 14:25       ` Leizhen (ThunderTown)

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