linux-kernel - Re: [PATCH v2 7/7] xen/arm: set the system time in Xen via the XENPF

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: <4039287.QS1nrAMb0E@wuerfel>
Date:	Tue, 10 Nov 2015 13:39:44 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	xen-devel@...ts.xensource.com, linux-kernel@...r.kernel.org,
	Ian.Campbell@...rix.com
Subject: Re: [PATCH v2 7/7] xen/arm: set the system time in Xen via the XENPF_settime64 hypercall

On Tuesday 10 November 2015 11:57:55 Stefano Stabellini wrote:
> +       op.u.settime64.nsecs = now.tv_nsec;
> +       op.u.settime64.system_time = arch_timer_read_counter() * (u64)NSEC_PER_SEC;
> +       do_div(op.u.settime64.system_time, arch_timer_get_rate());

NSEC_PER_SEC is a large number, doesn't that multiplication overflow the
64-bit system_time variable?

> +       printk("GTOD: Setting to %llu.%u at %llu\n",

				   %llu.%09u

so you get the leading zeroes.

> +              op.u.settime64.secs,
> +              op.u.settime64.nsecs,
> +              op.u.settime64.system_time);
> +       (void)HYPERVISOR_platform_op(&op);

	Arnd
--
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/