From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Date: Fri, 9 May 2014 15:11:27 +0000 (-0400)
Subject: x86, vdso, time: Cast tv_nsec to u64 for proper shifting in update_vsyscall()
X-Git-Tag: omap-for-v3.16/fixes-against-rc1~198^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=28b92e09e25bdc0ae864b22eacf195a74f861389;p=pandora-kernel.git

x86, vdso, time: Cast tv_nsec to u64 for proper shifting in update_vsyscall()

With tk->wall_to_monotonic.tv_nsec being a 32-bit value on 32-bit
systems, (tk->wall_to_monotonic.tv_nsec << tk->shift) in update_vsyscall()
may lose upper bits or, worse, add them since compiler will do this:
	(u64)(tk->wall_to_monotonic.tv_nsec << tk->shift)
instead of
	((u64)tk->wall_to_monotonic.tv_nsec << tk->shift)

So if, for example, tv_nsec is 0x800000 and shift is 8 we will end up
with 0xffffffff80000000 instead of 0x80000000. And then we are stuck in
the subsequent 'while' loop.

We need an explicit cast.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1399648287-15178-1-git-send-email-boris.ostrovsky@oracle.com
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <stable@vger.kernel.org> # v3.14
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---

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