2023-04-14 03:18:26

by Hao Zeng

Subject: [PATCH v2] cpupower:Fix resource leaks in sysfs_get_enabled()

When the read return value is equal to 1, a file handle leak will occur

Signed-off-by: Hao Zeng <[email protected]>
Suggested-by: Shuah Khan <[email protected]>
---
tools/power/cpupower/lib/powercap.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
index 0ce29ee4c2e4..02ec5b0bff6b 100644
--- a/tools/power/cpupower/lib/powercap.c
+++ b/tools/power/cpupower/lib/powercap.c
@@ -40,7 +40,7 @@ static int sysfs_get_enabled(char *path, int *mode)
{
int fd;
char yes_no;
-
+ int ret = 0;
*mode = 0;

fd = open(path, O_RDONLY);
@@ -48,17 +48,18 @@ static int sysfs_get_enabled(char *path, int *mode)
return -1;

if (read(fd, &yes_no, 1) != 1) {
- close(fd);
- return -1;
+ ret = -1;
+ goto err;
}

- if (yes_no == '1') {
- *mode = 1;
- return 0;
- } else if (yes_no == '0') {
- return 0;
+ if (yes_no != '1' || yes_no != '0') {
+ ret = -1;
+ goto err;
}
- return -1;
+ *mode = yes_no - '0';
+err:
+ close(fd);
+ return ret;
}

int powercap_get_enabled(int *mode)
--
2.37.2


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2023-04-14 16:44:35

by Shuah Khan

Subject: Re: [PATCH v2] cpupower:Fix resource leaks in sysfs_get_enabled()

On 4/13/23 21:08, Hao Zeng wrote:
> When the read return value is equal to 1, a file handle leak will occur
>

Would like a bit more information on how the error paths are
redone, since memory leak isn't the only one that is fixed.

> Signed-off-by: Hao Zeng <[email protected]>
> Suggested-by: Shuah Khan <[email protected]>
> ---
> tools/power/cpupower/lib/powercap.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
> index 0ce29ee4c2e4..02ec5b0bff6b 100644
> --- a/tools/power/cpupower/lib/powercap.c
> +++ b/tools/power/cpupower/lib/powercap.c
> @@ -40,7 +40,7 @@ static int sysfs_get_enabled(char *path, int *mode)
> {
> int fd;
> char yes_no;
> -
> + int ret = 0;
> *mode = 0;
>
> fd = open(path, O_RDONLY);
> @@ -48,17 +48,18 @@ static int sysfs_get_enabled(char *path, int *mode)
> return -1;
>
> if (read(fd, &yes_no, 1) != 1) {
> - close(fd);
> - return -1;
> + ret = -1;
> + goto err;
> }
>
> - if (yes_no == '1') {
> - *mode = 1;
> - return 0;
> - } else if (yes_no == '0') {
> - return 0;
> + if (yes_no != '1' || yes_no != '0') {
> + ret = -1;
> + goto err;
> }
> - return -1;
> + *mode = yes_no - '0';

I am not seeing much value in changing the above paths.
Leave them unchanged.

> +err:
> + close(fd);
> + return ret;
> }
>
> int powercap_get_enabled(int *mode)

thanks,
-- Shuah

2023-04-17 08:23:31

by Hao Zeng

Subject: Re: [PATCH v2] cpupower:Fix resource leaks in sysfs_get_enabled()

Hi Shuah , Thanks very much for your review!
I tried to understand what you said as best I could and provided V3.
I look forward to your review again, it will help me a lot!

Best regards
-- Hao

On Fri, 2023-04-14 at 10:41 -0600, Shuah Khan wrote:
> On 4/13/23 21:08, Hao Zeng wrote:
> > When the read return value is equal to 1, a file handle leak will
> > occur
> >
>
> Would like a bit more information on how the error paths are
> redone, since memory leak isn't the only one that is fixed.
>
> > Signed-off-by: Hao Zeng <[email protected]>
> > Suggested-by: Shuah Khan <[email protected]>
> > ---
> >   tools/power/cpupower/lib/powercap.c | 19 ++++++++++---------
> >   1 file changed, 10 insertions(+), 9 deletions(-)
> >
> > diff --git a/tools/power/cpupower/lib/powercap.c
> > b/tools/power/cpupower/lib/powercap.c
> > index 0ce29ee4c2e4..02ec5b0bff6b 100644
> > --- a/tools/power/cpupower/lib/powercap.c
> > +++ b/tools/power/cpupower/lib/powercap.c
> > @@ -40,7 +40,7 @@ static int sysfs_get_enabled(char *path, int
> > *mode)
> >   {
> >         int fd;
> >         char yes_no;
> > -
> > +       int ret = 0;
> >         *mode = 0;
> >  
> >         fd = open(path, O_RDONLY);
> > @@ -48,17 +48,18 @@ static int sysfs_get_enabled(char *path, int
> > *mode)
> >                 return -1;
> >  
> >         if (read(fd, &yes_no, 1) != 1) {
> > -               close(fd);
> > -               return -1;
> > +               ret = -1;
> > +               goto err;
> >         }
> >  
> > -       if (yes_no == '1') {
> > -               *mode = 1;
> > -               return 0;
> > -       } else if (yes_no == '0') {
> > -               return 0;
> > +       if (yes_no != '1' || yes_no != '0') {
> > +               ret = -1;
> > +               goto err;
> >         }
> > -       return -1;
> > +       *mode = yes_no - '0';
>
> I am not seeing much value in changing the above paths.
> Leave them unchanged.
>
> > +err:
> > +       close(fd);
> > +       return ret;
> >   }
> >  
> >   int powercap_get_enabled(int *mode)
>
> thanks,
> -- Shuah