* [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config()
@ 2026-09-27 6:00 Mariia Nikitash
2026-09-28 10:02 ` Ian Abbott
2026-11-12 18:39 ` Kees Cook
0 siblings, 2 replies; 5+ messages in thread
From: Mariia Nikitash @ 2026-09-27 6:00 UTC (permalink / raw)
To: abbotti, hsweeten
Cc: linux-kernel, linux-hardening, morbo, kees, justinstitt,
codemender-patching+linux, Mariia Nikitash
From: Bill Wendling <morbo@google.com>
do_dev_config() builds a space-separated list of bonded devices in
devpriv->name by formatting each "minor:subdev " pair into a temporary
stack buffer with snprintf() and appending it with strlcat() in a loop.
In preparation for removing the deprecated strlcat() API[1], use struct
seq_buf and seq_buf_printf() to format each entry directly into
devpriv->name. This avoids repeated rescanning of devpriv->name and
eliminates the temporary buffer.
Link: https://github.com/KSPP/linux/issues/370 [1]
Cc: codemender-patching+linux@google.com
Assisted-by: LLM
Signed-off-by: Bill Wendling <morbo@google.com>
Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>
---
drivers/comedi/drivers/comedi_bond.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c
index 8e10ecab4f0d..a10cfbd04c72 100644
--- a/drivers/comedi/drivers/comedi_bond.c
+++ b/drivers/comedi/drivers/comedi_bond.c
@@ -39,6 +39,7 @@
#include <linux/module.h>
#include <linux/string.h>
+#include <linux/seq_buf.h>
#include <linux/slab.h>
#include <linux/comedi.h>
#include <linux/comedi/comedilib.h>
@@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
{
struct comedi_bond_private *devpriv = dev->private;
DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);
+ struct seq_buf s;
int i;
memset(&devs_opened, 0, sizeof(devs_opened));
- devpriv->name[0] = 0;
+ seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));
/*
* Loop through all comedi devices specified on the command-line,
* building our device list.
@@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
}
devpriv->devs = devs;
devpriv->devs[devpriv->ndevs++] = bdev;
- {
- /* Append dev:subdev to devpriv->name */
- char buf[20];
-
- snprintf(buf, sizeof(buf), "%u:%u ",
- bdev->minor, bdev->subdev);
- strlcat(devpriv->name, buf,
- sizeof(devpriv->name));
- }
+
+ /* Append dev:subdev to devpriv->name */
+ seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev);
}
}
@@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
return -EINVAL;
}
+ seq_buf_str(&s);
+
return 0;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config()
2026-09-27 6:00 [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config() Mariia Nikitash
@ 2026-09-28 10:02 ` Ian Abbott
2026-11-12 18:39 ` Kees Cook
1 sibling, 0 replies; 5+ messages in thread
From: Ian Abbott @ 2026-09-28 10:02 UTC (permalink / raw)
To: Mariia Nikitash, hsweeten
Cc: linux-kernel, linux-hardening, morbo, kees, justinstitt,
codemender-patching+linux
On 27/09/2026 07:00, Mariia Nikitash wrote:
> From: Bill Wendling <morbo@google.com>
>
> do_dev_config() builds a space-separated list of bonded devices in
> devpriv->name by formatting each "minor:subdev " pair into a temporary
> stack buffer with snprintf() and appending it with strlcat() in a loop.
>
> In preparation for removing the deprecated strlcat() API[1], use struct
> seq_buf and seq_buf_printf() to format each entry directly into
> devpriv->name. This avoids repeated rescanning of devpriv->name and
> eliminates the temporary buffer.
>
> Link: https://github.com/KSPP/linux/issues/370 [1]
> Cc: codemender-patching+linux@google.com
> Assisted-by: LLM
> Signed-off-by: Bill Wendling <morbo@google.com>
> Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>
> ---
> drivers/comedi/drivers/comedi_bond.c | 18 ++++++++----------
> 1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c
> index 8e10ecab4f0d..a10cfbd04c72 100644
> --- a/drivers/comedi/drivers/comedi_bond.c
> +++ b/drivers/comedi/drivers/comedi_bond.c
> @@ -39,6 +39,7 @@
>
> #include <linux/module.h>
> #include <linux/string.h>
> +#include <linux/seq_buf.h>
> #include <linux/slab.h>
> #include <linux/comedi.h>
> #include <linux/comedi/comedilib.h>
> @@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> {
> struct comedi_bond_private *devpriv = dev->private;
> DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);
> + struct seq_buf s;
> int i;
>
> memset(&devs_opened, 0, sizeof(devs_opened));
> - devpriv->name[0] = 0;
> + seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));
> /*
> * Loop through all comedi devices specified on the command-line,
> * building our device list.
> @@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> }
> devpriv->devs = devs;
> devpriv->devs[devpriv->ndevs++] = bdev;
> - {
> - /* Append dev:subdev to devpriv->name */
> - char buf[20];
> -
> - snprintf(buf, sizeof(buf), "%u:%u ",
> - bdev->minor, bdev->subdev);
> - strlcat(devpriv->name, buf,
> - sizeof(devpriv->name));
> - }
> +
> + /* Append dev:subdev to devpriv->name */
> + seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev);
> }
> }
>
> @@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> return -EINVAL;
> }
>
> + seq_buf_str(&s);
> +
> return 0;
> }
>
Looks good, thanks!
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
--
-=( Ian Abbott <abbotti@mev.co.uk> || MEV Ltd. is a company )=-
-=( registered in England & Wales. Regd. number: 02862268. )=-
-=( Regd. addr.: S11 & 12 Building 67, Europa Business Park, )=-
-=( Bird Hall Lane, STOCKPORT, SK3 0XA, UK. || www.mev.co.uk )=-
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config()
2026-09-27 6:00 [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config() Mariia Nikitash
2026-09-28 10:02 ` Ian Abbott
@ 2026-11-12 18:39 ` Kees Cook
2026-11-12 20:16 ` Mariia Nikitash
1 sibling, 1 reply; 5+ messages in thread
From: Kees Cook @ 2026-11-12 18:39 UTC (permalink / raw)
To: Mariia Nikitash
Cc: abbotti, hsweeten, linux-kernel, linux-hardening, morbo,
justinstitt, codemender-patching+linux
On Sat, Sep 26, 2026 at 11:00:00PM -0700, Mariia Nikitash wrote:
> From: Bill Wendling <morbo@google.com>
>
> do_dev_config() builds a space-separated list of bonded devices in
> devpriv->name by formatting each "minor:subdev " pair into a temporary
> stack buffer with snprintf() and appending it with strlcat() in a loop.
>
> In preparation for removing the deprecated strlcat() API[1], use struct
> seq_buf and seq_buf_printf() to format each entry directly into
> devpriv->name. This avoids repeated rescanning of devpriv->name and
> eliminates the temporary buffer.
>
> Link: https://github.com/KSPP/linux/issues/370 [1]
> Cc: codemender-patching+linux@google.com
> Assisted-by: LLM
> Signed-off-by: Bill Wendling <morbo@google.com>
> Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>
> ---
> drivers/comedi/drivers/comedi_bond.c | 18 ++++++++----------
> 1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c
> index 8e10ecab4f0d..a10cfbd04c72 100644
> --- a/drivers/comedi/drivers/comedi_bond.c
> +++ b/drivers/comedi/drivers/comedi_bond.c
> @@ -39,6 +39,7 @@
>
> #include <linux/module.h>
> #include <linux/string.h>
> +#include <linux/seq_buf.h>
> #include <linux/slab.h>
> #include <linux/comedi.h>
> #include <linux/comedi/comedilib.h>
> @@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> {
> struct comedi_bond_private *devpriv = dev->private;
> DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);
> + struct seq_buf s;
> int i;
>
> memset(&devs_opened, 0, sizeof(devs_opened));
> - devpriv->name[0] = 0;
> + seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));
> /*
> * Loop through all comedi devices specified on the command-line,
> * building our device list.
> @@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> }
> devpriv->devs = devs;
> devpriv->devs[devpriv->ndevs++] = bdev;
> - {
> - /* Append dev:subdev to devpriv->name */
> - char buf[20];
> -
> - snprintf(buf, sizeof(buf), "%u:%u ",
> - bdev->minor, bdev->subdev);
> - strlcat(devpriv->name, buf,
> - sizeof(devpriv->name));
> - }
> +
> + /* Append dev:subdev to devpriv->name */
> + seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev);
> }
> }
>
> @@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> return -EINVAL;
> }
>
> + seq_buf_str(&s);
If this hasn't been applied yet, a v2 with the above changed to the
now-available seq_buf_terminate() would be nice to have. Either way:
Reviewed-by: Kees Cook <kees@kernel.org>
> +
> return 0;
> }
>
> --
> 2.43.0
>
--
Kees Cook
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config()
2026-11-12 18:39 ` Kees Cook
@ 2026-11-12 20:16 ` Mariia Nikitash
2026-11-12 20:32 ` Kees Cook
0 siblings, 1 reply; 5+ messages in thread
From: Mariia Nikitash @ 2026-11-12 20:16 UTC (permalink / raw)
To: Kees Cook
Cc: abbotti, hsweeten, linux-kernel, linux-hardening, morbo,
justinstitt, codemender-patching+linux
Hi!
On Thu, Nov 12, 2026 at 10:39 AM Kees Cook <kees@kernel.org> wrote:
>
> On Sat, Sep 26, 2026 at 11:00:00PM -0700, Mariia Nikitash wrote:
> > From: Bill Wendling <morbo@google.com>
> >
> > do_dev_config() builds a space-separated list of bonded devices in
> > devpriv->name by formatting each "minor:subdev " pair into a temporary
> > stack buffer with snprintf() and appending it with strlcat() in a loop.
> >
> > In preparation for removing the deprecated strlcat() API[1], use struct
> > seq_buf and seq_buf_printf() to format each entry directly into
> > devpriv->name. This avoids repeated rescanning of devpriv->name and
> > eliminates the temporary buffer.
> >
> > Link: https://github.com/KSPP/linux/issues/370 [1]
> > Cc: codemender-patching+linux@google.com
> > Assisted-by: LLM
> > Signed-off-by: Bill Wendling <morbo@google.com>
> > Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>
> > ---
> > drivers/comedi/drivers/comedi_bond.c | 18 ++++++++----------
> > 1 file changed, 8 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/comedi/drivers/comedi_bond.c b/drivers/comedi/drivers/comedi_bond.c
> > index 8e10ecab4f0d..a10cfbd04c72 100644
> > --- a/drivers/comedi/drivers/comedi_bond.c
> > +++ b/drivers/comedi/drivers/comedi_bond.c
> > @@ -39,6 +39,7 @@
> >
> > #include <linux/module.h>
> > #include <linux/string.h>
> > +#include <linux/seq_buf.h>
> > #include <linux/slab.h>
> > #include <linux/comedi.h>
> > #include <linux/comedi/comedilib.h>
> > @@ -170,10 +171,11 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> > {
> > struct comedi_bond_private *devpriv = dev->private;
> > DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);
> > + struct seq_buf s;
> > int i;
> >
> > memset(&devs_opened, 0, sizeof(devs_opened));
> > - devpriv->name[0] = 0;
> > + seq_buf_init(&s, devpriv->name, sizeof(devpriv->name));
> > /*
> > * Loop through all comedi devices specified on the command-line,
> > * building our device list.
> > @@ -250,15 +252,9 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> > }
> > devpriv->devs = devs;
> > devpriv->devs[devpriv->ndevs++] = bdev;
> > - {
> > - /* Append dev:subdev to devpriv->name */
> > - char buf[20];
> > -
> > - snprintf(buf, sizeof(buf), "%u:%u ",
> > - bdev->minor, bdev->subdev);
> > - strlcat(devpriv->name, buf,
> > - sizeof(devpriv->name));
> > - }
> > +
> > + /* Append dev:subdev to devpriv->name */
> > + seq_buf_printf(&s, "%u:%u ", bdev->minor, bdev->subdev);
> > }
> > }
> >
> > @@ -267,6 +263,8 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
> > return -EINVAL;
> > }
> >
> > + seq_buf_str(&s);
>
> If this hasn't been applied yet, a v2 with the above changed to the
> now-available seq_buf_terminate() would be nice to have. Either way:
>
> Reviewed-by: Kees Cook <kees@kernel.org>
Thanks for the review! This patch has already been merged, but I'd be
happy to send a follow up patch with seq_buf_terminate() if you'd
like.
>
>
> > +
> > return 0;
> > }
> >
> > --
> > 2.43.0
> >
>
> --
> Kees Cook
Best,
Mariia
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config()
2026-11-12 20:16 ` Mariia Nikitash
@ 2026-11-12 20:32 ` Kees Cook
0 siblings, 0 replies; 5+ messages in thread
From: Kees Cook @ 2026-11-12 20:32 UTC (permalink / raw)
To: Mariia Nikitash
Cc: abbotti, hsweeten, linux-kernel, linux-hardening, morbo,
justinstitt, codemender-patching+linux
On Thu, Nov 12, 2026 at 12:16:11PM -0800, Mariia Nikitash wrote:
> Thanks for the review! This patch has already been merged, but I'd be
> happy to send a follow up patch with seq_buf_terminate() if you'd
> like.
Nah, it's fine. :) I don't see value in the churn since the binary
output will be identical.
--
Kees Cook
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-11-12 20:32 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2026-09-27 6:00 [PATCH] comedi: comedi_bond: Refactor strlcat() to seq_buf in do_dev_config() Mariia Nikitash
2026-09-28 10:02 ` Ian Abbott
2026-11-12 18:39 ` Kees Cook
2026-11-12 20:16 ` Mariia Nikitash
2026-11-12 20:32 ` Kees Cook
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