Re: [PATCH] lib/vsprintf.c: increase the size of the field_width variable

From: Joe Perches
Date: Wed Sep 09 2015 - 12:55:22 EST


On Wed, 2015-09-09 at 12:36 -0400, Tejun Heo wrote:
> On Wed, Sep 09, 2015 at 09:33:52AM -0700, Joe Perches wrote:
> > On Wed, 2015-09-09 at 12:13 +0200, Maurizio Lombardi wrote:
> > > When printing a bitmap using the "%*pb[l]" printk format
> > > a 16 bit variable (field_width) is used to store the size of the bitmap.
> > > In some cases 16 bits are not sufficient, the variable overflows and
> > > printk does not work as expected.
> >
> > If more than 16 bits are necessary, it couldn't work
> > as a single printk is limited to 1024 bytes.
>
> It's weird to fail silently tho. What we can do is just capping it at
> 16bit max and append something to indicate that the bitmap has been
> truncated if truncation actually happened.

It might be reasonable to output ... after the last
comma or dash of the bitmap output when buf >= end.

It also might be better to not reuse spec in
bitmap_string and bitmap_list_string.


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