Hi Greg,
On Tue, Nov 18, 2014 at 9:06 PM, <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> 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>.
I believe the crash can only happen on trees including
commit 6e2c89d16d987e6e11c531b039a42d3f5f1d7c32
Author: viresh kumar <viresh.kumar@xxxxxxxxxx>
Date: Tue Mar 4 11:43:59 2014 +0800
cpufreq: move call to __find_governor() to cpufreq_init_policy()
which appeared in v3.15-rc1.
AFAIK it hasn't been backported (yet :-) to v3.12.x, v3.13.x or v3.14.x.
> 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;
> }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html