[PATCH v2] Fix display of Maximum Memory

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE2414d LANDED

Landed in mainline as f1dbc1c5c70d on 2020-01-25.

6 messages, 5 authors, 2020-01-29 · open the first message on its own page

[PATCH v2] Fix display of Maximum Memory

From: Michael Bringmann <hidden>
Date: 2020-01-15 14:54:28 

Correct overflow problem in calculation+display of Maximum Memory
value to syscfg where 32bits is insufficient.

Signed-off-by: Michael Bringmann <redacted>
---
 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

Re: [PATCH v2] Fix display of Maximum Memory

From: Christophe Leroy <hidden>
Date: 2020-01-15 14:55:57 


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 <redacted>
Reviewed-by: Christophe Leroy <redacted>
quoted hunk
---
  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

From: Tyrel Datwyler <tyreld@linux.ibm.com>
Date: 2020-01-16 00:08:18 

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 <tyreld@linux.ibm.com>
quoted hunk
Signed-off-by: Michael Bringmann <redacted>
---
 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

    

      From: Michael Ellerman <mpe@ellerman.id.au>

      Date: 2020-01-16 05:53:55 
    

  

  
Michael Bringmann [off-list ref] writes:
quoted hunk
Correct overflow problem in calculation+display of Maximum Memory
value to syscfg where 32bits is insufficient.

Signed-off-by: Michael Bringmann <redacted>
---
 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

    

      From: Michael Bringmann <hidden>

      Date: 2020-01-16 23:52:35 
    

  

  
On 1/15/20 11:53 PM, Michael Ellerman wrote:
quoted hunk
Michael Bringmann [off-list ref] writes:
quoted
Correct overflow problem in calculation+display of Maximum Memory
value to syscfg where 32bits is insufficient.

Signed-off-by: Michael Bringmann <redacted>
---
 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.

quoted
-	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.

quoted
+	maxmem += (u64)hugetlb_total_pages() * PAGE_SIZE;
hugetlb_total_pages() already returns unsigned long.

quoted
-	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
mwb@linux.ibm.com





  

    
Re: [PATCH v2] Fix display of Maximum Memory

    

      From: Michael Ellerman <hidden>

      Date: 2020-01-29 05:17:59 
    

  

  
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 <redacted>
Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/f1dbc1c5c70d0d4c60b5d467ba941fba167c12f6

cheers




    
  

  
    

      

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