linux-kernel - Re: [PATCH] lib/vsprintf.c: increase the size of the field

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1441899685.17219.158.camel@perches.com>
Date:	Thu, 10 Sep 2015 08:41:25 -0700
From:	Joe Perches <joe@...ches.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Maurizio Lombardi <mlombard@...hat.com>,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] lib/vsprintf.c: increase the size of the field_width
 variable

On Thu, 2015-09-10 at 10:36 -0400, Tejun Heo wrote:
> On Wed, Sep 09, 2015 at 12:26:39PM -0700, Joe Perches wrote:
> > > > %*pb is meant for smallish bitmaps, not big ones.
[]
> The use case isn't from me, but why not?

Imagine the output of the 500k bitmap if every other
bit is set.

%*pb isn't capable of multiple line output and
seq_printf output would also fail as it uses k.alloc
memory not vmalloc.

I think that a more limited mechanism might be to use a
multiple line oriented function like print_hex_debug
and not try to emit the entire thing in a single go.

> Why are we even copying the struct on invocations?
> Only some functions modify the values after all.
> We might as well pass around pointer to the struct
> and let the callees wihch modify them copy the
> fields in local vars like normal functions.

You are of course welcome and able to change it.

btw: the current implementation has a limitation
on 32 bit arches as it uses an int argument for the
unsigned long count of bits in a bitmap.

That's a bitmap that should not be printed anyway.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/