Re: FAILED: patch "[PATCH] timekeeping/vsyscall: Update VDSO data unconditionally" failed to apply to 5.3-stable tree

[Sasha Levin <sashal@kernel.org>]

On Mon, Nov 11, 2019 at 07:30:37AM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 5.3-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From 52338415cf4d4064ae6b8dd972dadbda841da4fa Mon Sep 17 00:00:00 2001
>From: Huacai Chen <chenhc@lemote.com>
>Date: Thu, 24 Oct 2019 11:28:29 +0800
>Subject: [PATCH] timekeeping/vsyscall: Update VDSO data unconditionally
>
>The update of the VDSO data is depending on __arch_use_vsyscall() returning
>True. This is a leftover from the attempt to map the features of various
>architectures 1:1 into generic code.
>
>The usage of __arch_use_vsyscall() in the actual vsyscall implementations
>got dropped and replaced by the requirement for the architecture code to
>return U64_MAX if the global clocksource is not usable in the VDSO.
>
>But the __arch_use_vsyscall() check in the update code stayed which causes
>the VDSO data to be stale or invalid when an architecture actually
>implements that function and returns False when the current clocksource is
>not usable in the VDSO.
>
>As a consequence the VDSO implementations of clock_getres(), time(),
>clock_gettime(CLOCK_.*_COARSE) operate on invalid data and return bogus
>information.
>
>Remove the __arch_use_vsyscall() check from the VDSO update function and
>update the VDSO data unconditionally.
>
>[ tglx: Massaged changelog and removed the now useless implementations in
>  	asm-generic/ARM64/MIPS ]
>
>Fixes: 44f57d788e7deecb50 ("timekeeping: Provide a generic update_vsyscall() implementation")
>Signed-off-by: Huacai Chen <chenhc@lemote.com>
>Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>Cc: Andy Lutomirski <luto@kernel.org>
>Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
>Cc: Arnd Bergmann <arnd@arndb.de>
>Cc: Paul Burton <paul.burton@mips.com>
>Cc: linux-mips@vger.kernel.org
>Cc: linux-arm-kernel@lists.infradead.org
>Cc: stable@vger.kernel.org
>Link: https://lkml.kernel.org/r/1571887709-11447-1-git-send-email-chenhc@lemote.com

I've dropped the mips bits because we don't have 24640f233b46 ("mips:
Add support for generic vDSO") on 5.3 and queued it up.

-- 
Thanks,
Sasha