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From: <gregkh@linuxfoundation.org>
To: suzuki.poulose@arm.com, catalin.marinas@arm.com,
	mark.rutland@arm.com, stable@vger.kernel.org,
	will.deacon@arm.com
Cc: <stable@vger.kernel.org>
Subject: FAILED: patch "[PATCH] arm64: Fix incorrect per-cpu usage for boot CPU" failed to apply to 4.4-stable tree
Date: Wed, 17 Aug 2016 14:51:43 +0200	[thread overview]
Message-ID: <147143830349244@kroah.com> (raw)


The patch below does not apply to the 4.4-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 9113c2aa05e9848cd4f1154abee17d4f265f012d Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Thu, 21 Jul 2016 11:12:55 +0100
Subject: [PATCH] arm64: Fix incorrect per-cpu usage for boot CPU

In smp_prepare_boot_cpu(), we invoke cpuinfo_store_boot_cpu to  store
the cpuinfo in a per-cpu ptr, before initialising the per-cpu offset for
the boot CPU. This patch reorders the sequence to make sure we initialise
the per-cpu offset before accessing the per-cpu area.

Commit 4b998ff1885eec ("arm64: Delay cpuinfo_store_boot_cpu") fixed the
issue where we modified the per-cpu area even before the kernel initialises
the per-cpu areas, but failed to wait until the boot cpu updated it's
offset.

Fixes: 4b998ff1885e ("arm64: Delay cpuinfo_store_boot_cpu")
Cc: <stable@vger.kernel.org> # 4.4+
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index c0a772560ab7..298dd745651e 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -436,9 +436,9 @@ void __init smp_cpus_done(unsigned int max_cpus)
 
 void __init smp_prepare_boot_cpu(void)
 {
+	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
 	cpuinfo_store_boot_cpu();
 	save_boot_cpu_run_el();
-	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
 }
 
 static u64 __init of_get_cpu_mpidr(struct device_node *dn)


             reply	other threads:[~2016-08-17 12:58 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-17 12:51 gregkh [this message]
2016-08-17 16:03 ` FAILED: patch "[PATCH] arm64: Fix incorrect per-cpu usage for boot CPU" failed to apply to 4.4-stable tree Suzuki K Poulose

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