[dm-devel] [PATCH 1/4] libmultipath: fix sysfs dev_loss_tmo parsing

[Benjamin Marzinski]

On Thu, Jul 02, 2020 at 02:31:17PM +0000, Martin Wilck wrote:
> On Wed, 2020-07-01 at 17:39 -0500, Benjamin Marzinski wrote:
> > dev_loss_tmo is a u32 value. However the kernel sysfs code prints it
> > as
> > a signed integer. This means that if dev_loss_tmo is above INT_MAX,
> > the
> > sysfs value will be a negative number. Parsing this was causing
> > sysfs_set_rport_tmo() to fail.
> > 
> > Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> 
> Thanks for catching this. I think it can be fixed simpler, because 
> strtoul() parses negative values just fine. See below.

Sure. Lets go with that.

-Ben

> 
> Regards,
> Martin
> 
> >From 16eca9b0f340a13fee0c28ae52dffa578193f015 Mon Sep 17 00:00:00 2001
> From: Benjamin Marzinski <bmarzins at redhat.com>
> Date: Wed, 1 Jul 2020 17:39:33 -0500
> Subject: [PATCH] libmultipath: fix sysfs dev_loss_tmo parsing
> 
> dev_loss_tmo is a u32 value. However the kernel sysfs code prints it as
> a signed integer. This means that if dev_loss_tmo is above INT_MAX, the
> sysfs value will be a negative number. Parsing this was causing
> sysfs_set_rport_tmo() to fail.
> 
> Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
>  libmultipath/discovery.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
> index 1d542ea..3c9803a 100644
> --- a/libmultipath/discovery.c
> +++ b/libmultipath/discovery.c
> @@ -581,7 +581,7 @@ sysfs_set_rport_tmo(struct multipath *mpp, struct path *pp)
>  	struct udev_device *rport_dev = NULL;
>  	char value[16], *eptr;
>  	char rport_id[32];
> -	unsigned long long tmo = 0;
> +	unsigned int tmo;
>  	int ret;
>  
>  	sprintf(rport_id, "rport-%d:%d-%d",
> @@ -605,8 +605,8 @@ sysfs_set_rport_tmo(struct multipath *mpp, struct path *pp)
>  			"error %d", rport_id, -ret);
>  		goto out;
>  	}
> -	tmo = strtoull(value, &eptr, 0);
> -	if (value == eptr || tmo == ULLONG_MAX) {
> +	tmo = strtoul(value, &eptr, 0);
> +	if (value == eptr) {
>  		condlog(0, "%s: Cannot parse dev_loss_tmo "
>  			"attribute '%s'", rport_id, value);
>  		goto out;
> -- 
> 2.26.2