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cpufreq: Avoid crash in resume on SMP without OPP

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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@glider.be>
Fixes: 8414809c6a (cpufreq: Preserve policy structure across suspend/resume)
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Geert Uytterhoeven 2014-11-04 17:05:25 +01:00 committed by Rafael J. Wysocki
parent 7179621023
commit 09712f557b
1 changed files with 2 additions and 1 deletions
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3
drivers/cpufreq/cpufreq.c
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@ -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;
}