linux-kernel - Re: [PATCH 1/2] eventfd: reorganize the code to simplify new flags

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: <4A9672A5.60004@gnu.org>
Date:	Thu, 27 Aug 2009 13:48:53 +0200
From:	Paolo Bonzini <bonzini@....org>
To:	"Michael S. Tsirkin" <mst@...hat.com>
CC:	davidel@...ilserver.org, avi@...hat.com, gleb@...hat.com,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] eventfd: reorganize the code to simplify new flags

On 08/20/2009 05:57 PM, Michael S. Tsirkin wrote:
> +static inline int eventfd_writeable(struct eventfd_ctx *ctx, u64 n)
> +{
> +	return ULLONG_MAX - n>  ctx->count;
> +}
> +
> +static inline void eventfd_dowrite(struct eventfd_ctx *ctx, u64 ucnt)
> +{
> +	if (eventfd_writeable(ctx, ucnt))
> +		ucnt = ULLONG_MAX - ctx->count;
> +
> +	ctx->count += ucnt;

In any case, this usage of eventfd_writeable is wrong: the code was like 
this:

-	if (ULLONG_MAX - ctx->count < n)
-		n = (int) (ULLONG_MAX - ctx->count);
-	ctx->count += n;
+	eventfd_dowrite(ctx, n);

and so it should be !eventfd_writable.  (This smelled when I was editing 
patch 2, so I went back and checked patch 1).

Paolo
--
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/