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[PATCH 5.1 119/122] y2038: Make CONFIG_64BIT_TIME unconditional
- From: Greg Kroah-Hartman <gregkh at linuxfoundation dot org>
- To: linux-kernel at vger dot kernel dot org
- Cc: Greg Kroah-Hartman <gregkh at linuxfoundation dot org>, stable at vger dot kernel dot org, Arnd Bergmann <arnd at arndb dot de>, Thomas Gleixner <tglx at linutronix dot de>, Joseph Myers <joseph at codesourcery dot com>, libc-alpha at sourceware dot org, linux-api at vger dot kernel dot org, Deepa Dinamani <deepa dot kernel at gmail dot com>, Lukasz Majewski <lukma at denx dot de>, Stepan Golosunov <stepan at golosunov dot pp dot ru>
- Date: Thu, 23 May 2019 21:07:21 +0200
- Subject: [PATCH 5.1 119/122] y2038: Make CONFIG_64BIT_TIME unconditional
- References: <20190523181705.091418060@linuxfoundation.org>
From: Arnd Bergmann <arnd@arndb.de>
commit f3d964673b2f1c5d5c68c77273efcf7103eed03b upstream.
As Stepan Golosunov points out, there is a small mistake in the
get_timespec64() function in the kernel. It was originally added under the
assumption that CONFIG_64BIT_TIME would get enabled on all 32-bit and
64-bit architectures, but when the conversion was done, it was only turned
on for 32-bit ones.
The effect is that the get_timespec64() function never clears the upper
half of the tv_nsec field for 32-bit tasks in compat mode. Clearing this is
required for POSIX compliant behavior of functions that pass a 'timespec'
structure with a 64-bit tv_sec and a 32-bit tv_nsec, plus uninitialized
padding.
The easiest fix for linux-5.1 is to just make the Kconfig symbol
unconditional, as it was originally intended. As a follow-up, the #ifdef
CONFIG_64BIT_TIME can be removed completely..
Note: for native 32-bit mode, no change is needed, this works as
designed and user space should never need to clear the upper 32
bits of the tv_nsec field, in or out of the kernel.
Fixes: 00bf25d693e7 ("y2038: use time32 syscall names on 32-bit")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Joseph Myers <joseph@codesourcery.com>
Cc: libc-alpha@sourceware.org
Cc: linux-api@vger.kernel.org
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Lukasz Majewski <lukma@denx.de>
Cc: Stepan Golosunov <stepan@golosunov.pp.ru>
Link: https://lore.kernel.org/lkml/20190422090710.bmxdhhankurhafxq@sghpc.golosunov.pp.ru/
Link: https://lkml.kernel.org/r/20190429131951.471701-1-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -764,7 +764,7 @@ config COMPAT_OLD_SIGACTION
bool
config 64BIT_TIME
- def_bool ARCH_HAS_64BIT_TIME
+ def_bool y
help
This should be selected by all architectures that need to support
new system calls with a 64-bit time_t. This is relevant on all 32-bit