From 09712f557b31838092e1f22a5f2dd131a843a3de Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 4 Nov 2014 17:05:25 +0100 Subject: 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 : [] lr : [] 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 Fixes: 8414809c6a1e (cpufreq: Preserve policy structure across suspend/resume) Cc: 3.12+ # 3.12+ Signed-off-by: Rafael J. Wysocki diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 644b54e..4473eba 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; } -- cgit v0.10.2