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* [PATCH] selftests/vm: Fix map_hugetlb length used for testing read and write
@ 2020-02-06  8:42 Christophe Leroy
  2020-02-15  6:49 ` Leonardo Bras
  0 siblings, 1 reply; 3+ messages in thread
From: Christophe Leroy @ 2020-02-06  8:42 UTC (permalink / raw)
  To: Michael Ellerman, Shuah Khan
  Cc: linux-mm, linuxppc-dev, linux-kernel, linux-kselftest

Commit fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and
page size in map_hugetlb") added the possibility to change the size
of memory mapped for the test, but left the read and write test using
the default value. This is unnoticed when mapping a length greater
than the default one, but segfaults otherwise.

Fix read_bytes() and write_bytes() by giving them the real length.

Also fix the call to munmap().

Fixes: fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 tools/testing/selftests/vm/map_hugetlb.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/vm/map_hugetlb.c b/tools/testing/selftests/vm/map_hugetlb.c
index 5a2d7b8efc40..6af951900aa3 100644
--- a/tools/testing/selftests/vm/map_hugetlb.c
+++ b/tools/testing/selftests/vm/map_hugetlb.c
@@ -45,20 +45,20 @@ static void check_bytes(char *addr)
 	printf("First hex is %x\n", *((unsigned int *)addr));
 }
 
-static void write_bytes(char *addr)
+static void write_bytes(char *addr, size_t length)
 {
 	unsigned long i;
 
-	for (i = 0; i < LENGTH; i++)
+	for (i = 0; i < length; i++)
 		*(addr + i) = (char)i;
 }
 
-static int read_bytes(char *addr)
+static int read_bytes(char *addr, size_t length)
 {
 	unsigned long i;
 
 	check_bytes(addr);
-	for (i = 0; i < LENGTH; i++)
+	for (i = 0; i < length; i++)
 		if (*(addr + i) != (char)i) {
 			printf("Mismatch at %lu\n", i);
 			return 1;
@@ -96,11 +96,11 @@ int main(int argc, char **argv)
 
 	printf("Returned address is %p\n", addr);
 	check_bytes(addr);
-	write_bytes(addr);
-	ret = read_bytes(addr);
+	write_bytes(addr, length);
+	ret = read_bytes(addr, length);
 
 	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
-	if (munmap(addr, LENGTH)) {
+	if (munmap(addr, length)) {
 		perror("munmap");
 		exit(1);
 	}
-- 
2.25.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] selftests/vm: Fix map_hugetlb length used for testing read and write
  2020-02-06  8:42 [PATCH] selftests/vm: Fix map_hugetlb length used for testing read and write Christophe Leroy
@ 2020-02-15  6:49 ` Leonardo Bras
  2020-02-17 14:10   ` Leonardo Bras
  0 siblings, 1 reply; 3+ messages in thread
From: Leonardo Bras @ 2020-02-15  6:49 UTC (permalink / raw)
  To: Christophe Leroy, Michael Ellerman, Shuah Khan
  Cc: linux-mm, linuxppc-dev, linux-kernel, linux-kselftest

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Hello Christophe, thank you for the patch.

On Thu, 2020-02-06 at 08:42 +0000, Christophe Leroy wrote:
> Commit fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and
> page size in map_hugetlb") added the possibility to change the size
> of memory mapped for the test, but left the read and write test using
> the default value. This is unnoticed when mapping a length greater
> than the default one, but segfaults otherwise.
> 
> Fix read_bytes() and write_bytes() by giving them the real length.
> 
> Also fix the call to munmap().
> 
> Fixes: fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb")
> Cc: stable@vger.kernel.org
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>  tools/testing/selftests/vm/map_hugetlb.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/testing/selftests/vm/map_hugetlb.c b/tools/testing/selftests/vm/map_hugetlb.c
> index 5a2d7b8efc40..6af951900aa3 100644
> --- a/tools/testing/selftests/vm/map_hugetlb.c
> +++ b/tools/testing/selftests/vm/map_hugetlb.c
> @@ -45,20 +45,20 @@ static void check_bytes(char *addr)
>  	printf("First hex is %x\n", *((unsigned int *)addr));
>  }
>  
> -static void write_bytes(char *addr)
> +static void write_bytes(char *addr, size_t length)
>  {
>  	unsigned long i;
>  
> -	for (i = 0; i < LENGTH; i++)
> +	for (i = 0; i < length; i++)
>  		*(addr + i) = (char)i;
>  }
>  
> -static int read_bytes(char *addr)
> +static int read_bytes(char *addr, size_t length)
>  {
>  	unsigned long i;
>  
>  	check_bytes(addr);
> -	for (i = 0; i < LENGTH; i++)
> +	for (i = 0; i < length; i++)
>  		if (*(addr + i) != (char)i) {
>  			printf("Mismatch at %lu\n", i);
>  			return 1;
> @@ -96,11 +96,11 @@ int main(int argc, char **argv)
>  
>  	printf("Returned address is %p\n", addr);
>  	check_bytes(addr);
> -	write_bytes(addr);
> -	ret = read_bytes(addr);
> +	write_bytes(addr, length);
> +	ret = read_bytes(addr, length);
>  
>  	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
> -	if (munmap(addr, LENGTH)) {
> +	if (munmap(addr, length)) {
>  		perror("munmap");
>  		exit(1);
>  	}

I agree with you, it's a needed fix.

FWIW:
Reviwed-by: Leonardo Bras <leonardo@linux.ibm.com>

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] selftests/vm: Fix map_hugetlb length used for testing read and write
  2020-02-15  6:49 ` Leonardo Bras
@ 2020-02-17 14:10   ` Leonardo Bras
  0 siblings, 0 replies; 3+ messages in thread
From: Leonardo Bras @ 2020-02-17 14:10 UTC (permalink / raw)
  To: Christophe Leroy, Michael Ellerman, Shuah Khan
  Cc: linux-mm, linuxppc-dev, linux-kernel, linux-kselftest

[-- Attachment #1: Type: text/plain, Size: 2599 bytes --]

On Sat, 2020-02-15 at 03:49 -0300, Leonardo Bras wrote:
> Hello Christophe, thank you for the patch.
> 
> On Thu, 2020-02-06 at 08:42 +0000, Christophe Leroy wrote:
> > Commit fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and
> > page size in map_hugetlb") added the possibility to change the size
> > of memory mapped for the test, but left the read and write test using
> > the default value. This is unnoticed when mapping a length greater
> > than the default one, but segfaults otherwise.
> > 
> > Fix read_bytes() and write_bytes() by giving them the real length.
> > 
> > Also fix the call to munmap().
> > 
> > Fixes: fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> > ---
> >  tools/testing/selftests/vm/map_hugetlb.c | 14 +++++++-------
> >  1 file changed, 7 insertions(+), 7 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/vm/map_hugetlb.c b/tools/testing/selftests/vm/map_hugetlb.c
> > index 5a2d7b8efc40..6af951900aa3 100644
> > --- a/tools/testing/selftests/vm/map_hugetlb.c
> > +++ b/tools/testing/selftests/vm/map_hugetlb.c
> > @@ -45,20 +45,20 @@ static void check_bytes(char *addr)
> >  	printf("First hex is %x\n", *((unsigned int *)addr));
> >  }
> >  
> > -static void write_bytes(char *addr)
> > +static void write_bytes(char *addr, size_t length)
> >  {
> >  	unsigned long i;
> >  
> > -	for (i = 0; i < LENGTH; i++)
> > +	for (i = 0; i < length; i++)
> >  		*(addr + i) = (char)i;
> >  }
> >  
> > -static int read_bytes(char *addr)
> > +static int read_bytes(char *addr, size_t length)
> >  {
> >  	unsigned long i;
> >  
> >  	check_bytes(addr);
> > -	for (i = 0; i < LENGTH; i++)
> > +	for (i = 0; i < length; i++)
> >  		if (*(addr + i) != (char)i) {
> >  			printf("Mismatch at %lu\n", i);
> >  			return 1;
> > @@ -96,11 +96,11 @@ int main(int argc, char **argv)
> >  
> >  	printf("Returned address is %p\n", addr);
> >  	check_bytes(addr);
> > -	write_bytes(addr);
> > -	ret = read_bytes(addr);
> > +	write_bytes(addr, length);
> > +	ret = read_bytes(addr, length);
> >  
> >  	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
> > -	if (munmap(addr, LENGTH)) {
> > +	if (munmap(addr, length)) {
> >  		perror("munmap");
> >  		exit(1);
> >  	}
> 
> I agree with you, it's a needed fix.
> 
> FWIW:
> Reviwed-by: Leonardo Bras <leonardo@linux.ibm.com>
Sorry, typo.
Reviewed-by: Leonardo Bras <leonardo@linux.ibm.com>

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^ permalink raw reply	[flat|nested] 3+ messages in thread

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2020-02-06  8:42 [PATCH] selftests/vm: Fix map_hugetlb length used for testing read and write Christophe Leroy
2020-02-15  6:49 ` Leonardo Bras
2020-02-17 14:10   ` Leonardo Bras

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