Re: [PATCH v2] Fix display of Maximum Memory
On Wed, 2020-01-15 at 14:53:59 UTC, Michael Bringmann wrote: > Correct overflow problem in calculation+display of Maximum Memory > value to syscfg where 32bits is insufficient. > > Signed-off-by: Michael Bringmann Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/f1dbc1c5c70d0d4c60b5d467ba941fba167c12f6 cheers
Re: [PATCH v2] Fix display of Maximum Memory
On 1/15/20 11:53 PM, Michael Ellerman wrote:
> Michael Bringmann writes:
>> Correct overflow problem in calculation+display of Maximum Memory
>> value to syscfg where 32bits is insufficient.
>>
>> Signed-off-by: Michael Bringmann
>> ---
>> arch/powerpc/platforms/pseries/lparcfg.c | 8
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c
>> b/arch/powerpc/platforms/pseries/lparcfg.c
>> index e33e8bc..f00411c 100644
>> --- a/arch/powerpc/platforms/pseries/lparcfg.c
>> +++ b/arch/powerpc/platforms/pseries/lparcfg.c
>> @@ -433,12 +433,12 @@ static void parse_em_data(struct seq_file *m)
>>
>> static void maxmem_data(struct seq_file *m)
>> {
>> -unsigned long maxmem = 0;
>> +u64 maxmem = 0;
>
> This is 64-bit only code, so u64 == unsigned long.
>
>> -maxmem += drmem_info->n_lmbs * drmem_info->lmb_size;
>> -maxmem += hugetlb_total_pages() * PAGE_SIZE;
>> +maxmem += (u64)drmem_info->n_lmbs * drmem_info->lmb_size;
>
> The only problem AFAICS is n_lmbs is int and lmb_size is u32, so this
> multiplication will overflow.
>
>> +maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE;
>
> hugetlb_total_pages() already returns unsigned long.
>
>> -seq_printf(m, "MaxMem=%ld\n", maxmem);
>> +seq_printf(m, "MaxMem=%llu\n", maxmem);
>> }
>
> This should be sufficient?
>
> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c
> b/arch/powerpc/platforms/pseries/lparcfg.c
> index e33e8bc4b69b..38c306551f76 100644
> --- a/arch/powerpc/platforms/pseries/lparcfg.c
> +++ b/arch/powerpc/platforms/pseries/lparcfg.c
> @@ -435,10 +435,10 @@ static void maxmem_data(struct seq_file *m)
> {
> unsigned long maxmem = 0;
>
> - maxmem += drmem_info->n_lmbs * drmem_info->lmb_size;
> + maxmem += (unsigned long)drmem_info->n_lmbs * drmem_info->lmb_size;
> maxmem += hugetlb_total_pages() * PAGE_SIZE;
>
> - seq_printf(m, "MaxMem=%ld\n", maxmem);
> + seq_printf(m, "MaxMem=%lu\n", maxmem);
> }
>
> static int pseries_lparcfg_data(struct seq_file *m, void *v)
>
>
> cheers
>
Trying it out.
--
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line 363-5196
External: (512) 286-5196
Cell: (512) 466-0650
m...@linux.ibm.com
Re: [PATCH v2] Fix display of Maximum Memory
Michael Bringmann writes:
> Correct overflow problem in calculation+display of Maximum Memory
> value to syscfg where 32bits is insufficient.
>
> Signed-off-by: Michael Bringmann
> ---
> arch/powerpc/platforms/pseries/lparcfg.c | 8
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c
> b/arch/powerpc/platforms/pseries/lparcfg.c
> index e33e8bc..f00411c 100644
> --- a/arch/powerpc/platforms/pseries/lparcfg.c
> +++ b/arch/powerpc/platforms/pseries/lparcfg.c
> @@ -433,12 +433,12 @@ static void parse_em_data(struct seq_file *m)
>
> static void maxmem_data(struct seq_file *m)
> {
> - unsigned long maxmem = 0;
> + u64 maxmem = 0;
This is 64-bit only code, so u64 == unsigned long.
> - maxmem += drmem_info->n_lmbs * drmem_info->lmb_size;
> - maxmem += hugetlb_total_pages() * PAGE_SIZE;
> + maxmem += (u64)drmem_info->n_lmbs * drmem_info->lmb_size;
The only problem AFAICS is n_lmbs is int and lmb_size is u32, so this
multiplication will overflow.
> + maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE;
hugetlb_total_pages() already returns unsigned long.
> - seq_printf(m, "MaxMem=%ld\n", maxmem);
> + seq_printf(m, "MaxMem=%llu\n", maxmem);
> }
This should be sufficient?
diff --git a/arch/powerpc/platforms/pseries/lparcfg.c
b/arch/powerpc/platforms/pseries/lparcfg.c
index e33e8bc4b69b..38c306551f76 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c
@@ -435,10 +435,10 @@ static void maxmem_data(struct seq_file *m)
{
unsigned long maxmem = 0;
- maxmem += drmem_info->n_lmbs * drmem_info->lmb_size;
+ maxmem += (unsigned long)drmem_info->n_lmbs * drmem_info->lmb_size;
maxmem += hugetlb_total_pages() * PAGE_SIZE;
- seq_printf(m, "MaxMem=%ld\n", maxmem);
+ seq_printf(m, "MaxMem=%lu\n", maxmem);
}
static int pseries_lparcfg_data(struct seq_file *m, void *v)
cheers
Re: [PATCH v2] Fix display of Maximum Memory
On 1/15/20 6:53 AM, Michael Bringmann wrote:
> Correct overflow problem in calculation+display of Maximum Memory
> value to syscfg where 32bits is insufficient.
>
Probably needs the following Fixes tag:
Fixes: 772b039fd9a7 ("powerpc/pseries: Export maximum memory value")
otherwise,
Reviewed-by: Tyrel Datwyler
> Signed-off-by: Michael Bringmann
> ---
> arch/powerpc/platforms/pseries/lparcfg.c | 8
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c
> b/arch/powerpc/platforms/pseries/lparcfg.c
> index e33e8bc..f00411c 100644
> --- a/arch/powerpc/platforms/pseries/lparcfg.c
> +++ b/arch/powerpc/platforms/pseries/lparcfg.c
> @@ -433,12 +433,12 @@ static void parse_em_data(struct seq_file *m)
>
> static void maxmem_data(struct seq_file *m)
> {
> - unsigned long maxmem = 0;
> + u64 maxmem = 0;
>
> - maxmem += drmem_info->n_lmbs * drmem_info->lmb_size;
> - maxmem += hugetlb_total_pages() * PAGE_SIZE;
> + maxmem += (u64)drmem_info->n_lmbs * drmem_info->lmb_size;
> + maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE;
>
> - seq_printf(m, "MaxMem=%ld\n", maxmem);
> + seq_printf(m, "MaxMem=%llu\n", maxmem);
> }
>
> static int pseries_lparcfg_data(struct seq_file *m, void *v)
>
Re: [PATCH v2] Fix display of Maximum Memory
Le 15/01/2020 à 15:53, Michael Bringmann a écrit :
Correct overflow problem in calculation+display of Maximum Memory
value to syscfg where 32bits is insufficient.
Signed-off-by: Michael Bringmann
Reviewed-by: Christophe Leroy
---
arch/powerpc/platforms/pseries/lparcfg.c | 8
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/lparcfg.c
b/arch/powerpc/platforms/pseries/lparcfg.c
index e33e8bc..f00411c 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c
@@ -433,12 +433,12 @@ static void parse_em_data(struct seq_file *m)
static void maxmem_data(struct seq_file *m)
{
- unsigned long maxmem = 0;
+ u64 maxmem = 0;
- maxmem += drmem_info->n_lmbs * drmem_info->lmb_size;
- maxmem += hugetlb_total_pages() * PAGE_SIZE;
+ maxmem += (u64)drmem_info->n_lmbs * drmem_info->lmb_size;
+ maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE;
- seq_printf(m, "MaxMem=%ld\n", maxmem);
+ seq_printf(m, "MaxMem=%llu\n", maxmem);
}
static int pseries_lparcfg_data(struct seq_file *m, void *v)
[PATCH v2] Fix display of Maximum Memory
Correct overflow problem in calculation+display of Maximum Memory
value to syscfg where 32bits is insufficient.
Signed-off-by: Michael Bringmann
---
arch/powerpc/platforms/pseries/lparcfg.c | 8
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/lparcfg.c
b/arch/powerpc/platforms/pseries/lparcfg.c
index e33e8bc..f00411c 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c
@@ -433,12 +433,12 @@ static void parse_em_data(struct seq_file *m)
static void maxmem_data(struct seq_file *m)
{
- unsigned long maxmem = 0;
+ u64 maxmem = 0;
- maxmem += drmem_info->n_lmbs * drmem_info->lmb_size;
- maxmem += hugetlb_total_pages() * PAGE_SIZE;
+ maxmem += (u64)drmem_info->n_lmbs * drmem_info->lmb_size;
+ maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE;
- seq_printf(m, "MaxMem=%ld\n", maxmem);
+ seq_printf(m, "MaxMem=%llu\n", maxmem);
}
static int pseries_lparcfg_data(struct seq_file *m, void *v)
--
1.8.3.1
