Messages in this thread | | | Subject | Re: [PATCH v2] EDAC/mc_sysfs: Add missing newlines when printing {max,dimm}_location | From | Xiongfeng Wang <> | Date | Thu, 17 Sep 2020 19:38:57 +0800 |
| |
Hi ,
On 2020/9/17 1:00, Borislav Petkov wrote: > On Mon, Sep 14, 2020 at 10:48:54AM +0800, Xiongfeng Wang wrote: >> @@ -813,15 +817,21 @@ static ssize_t mci_max_location_show(struct device *dev, >> char *data) >> { >> struct mem_ctl_info *mci = to_mci(dev); >> - int i; >> + int i, n; >> char *p = data; >> + unsigned int len = PAGE_SIZE; >> >> for (i = 0; i < mci->n_layers; i++) { >> - p += sprintf(p, "%s %d ", >> + n = snprintf(p, len, "%s %d ", >> edac_layer_name[mci->layers[i].type], >> mci->layers[i].size - 1); >> + p += n; >> + len -= n; > > What happens if that subtraction causes len to wrap around and become a > huge positive unsigned integer? > >> + if (!len) > > Would that test still work?
I am not sure if snprintf will return a value larger than its second input paramter 'size'. But we can also check if 'len' is less than 0. It's better.
> > IOW, I did this to your patch ontop. Note that I've moved the "p" > pointer incrementation after the length check so that the pointer > doesn't overflow too:
Thanks. I will add it in the next version.
> > --- > diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c > index bf0e075fb635..fa0551c81e63 100644 > --- a/drivers/edac/edac_mc_sysfs.c > +++ b/drivers/edac/edac_mc_sysfs.c > @@ -817,19 +817,22 @@ static ssize_t mci_max_location_show(struct device *dev, > char *data) > { > struct mem_ctl_info *mci = to_mci(dev); > - int i, n; > + int len = PAGE_SIZE; > char *p = data; > - unsigned int len = PAGE_SIZE; > + int i, n; > > for (i = 0; i < mci->n_layers; i++) { > n = snprintf(p, len, "%s %d ", > edac_layer_name[mci->layers[i].type], > mci->layers[i].size - 1); > - p += n; > + > len -= n; > - if (!len) > + if (len < 0)
Not sure whether we need to check 'len' equals to 0. if (len <= 0) ?
> goto out; > + > + p += n; > } > + > p += snprintf(p, len, "\n"); > out: > return p - data; >
Thanks, XIongfeng
| |