The patch below does not apply to the 3.12-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@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 09712f557b31838092e1f22a5f2dd131a843a3de Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Date: Tue, 4 Nov 2014 17:05:25 +0100
Subject: [PATCH] cpufreq: Avoid crash in resume on SMP without OPP
When resuming from s2ram on an SMP system without cpufreq operating
points (e.g. there's no "operating-points" property for the CPU node in
DT, or the platform doesn't use DT yet), the kernel crashes when
bringing CPU 1 online:
Enabling non-boot CPUs ...
CPU1: Booted secondary processor
Unable to handle kernel NULL pointer dereference at virtual address 0000003c
pgd = ee5e6b00
[0000003c] *pgd=6e579003, *pmd=6e588003, *pte=00000000
Internal error: Oops: a07 [#1] SMP ARM
Modules linked in:
CPU: 0 PID: 1246 Comm: s2ram Tainted: G W 3.18.0-rc3-koelsch-01614-g0377af242bb175c8-dirty #589
task: eeec5240 ti: ee704000 task.ti: ee704000
PC is at __cpufreq_add_dev.isra.24+0x24c/0x77c
LR is at __cpufreq_add_dev.isra.24+0x244/0x77c
pc : [<c0298efc>] lr : [<c0298ef4>] psr: 60000153
sp : ee705d48 ip : ee705d48 fp : ee705d84
r10: c04e0450 r9 : 00000000 r8 : 00000001
r7 : c05426a8 r6 : 00000001 r5 : 00000001 r4 : 00000000
r3 : 00000000 r2 : 00000000 r1 : 20000153 r0 : c0542734
Verify that policy is not NULL before dereferencing it to fix this.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Fixes: 8414809c6a1e (cpufreq: Preserve policy structure across suspend/resume)
Cc: 3.12+ <stable@xxxxxxxxxxxxxxx> # 3.12+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 644b54e1e7d1..4473eba1d6b0 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1022,7 +1022,8 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
- policy->governor = NULL;
+ if (policy)
+ policy->governor = NULL;
return policy;
}
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