On Monday, November 7, 2016, Gautham R Shenoy <e...@linux.vnet.ibm.com>
wrote:
> Hi Denis,
>
> On Fri, Nov 04, 2016 at 07:08:38AM -0400, Denis Kirjanov wrote:
>
> You can provide the config option with which this bug was found in the
> change log. I suppose you had enabled CONFIG_DEBUG_PREEMPT.
>
>
that's why I put the comment
> > [ 67.700897] BUG: using smp_processor_id() in preemptible
> [00000000] code: cat/7343
> > [ 67.700988] caller is .powernv_cpufreq_throttle_check+0x2c/0x710
> > [ 67.700998] CPU: 13 PID: 7343 Comm: cat Not tainted
> 4.8.0-rc5-dirty #1
> > [ 67.701038] Call Trace:
> > [ 67.701066] [c0000007d25b75b0] [c000000000971378]
> .dump_stack+0xe4/0x150 (unreliable)
> > [ 67.701153] [c0000007d25b7640] [c0000000005162e4]
> .check_preemption_disabled+0x134/0x150
> > [ 67.701238] [c0000007d25b76e0] [c0000000007b63ac]
> .powernv_cpufreq_throttle_check+0x2c/0x710
> > [ 67.701322] [c0000007d25b7790] [c0000000007b6d18]
> .powernv_cpufreq_target_index+0x288/0x360
> > [ 67.701407] [c0000007d25b7870] [c0000000007acee4]
> .__cpufreq_driver_target+0x394/0x8c0
> > [ 67.701491] [c0000007d25b7920] [c0000000007b22ac]
> .cpufreq_set+0x7c/0xd0
> > [ 67.701565] [c0000007d25b79b0] [c0000000007adf50]
> .store_scaling_setspeed+0x80/0xc0
> > [ 67.701650] [c0000007d25b7a40] [c0000000007ae270]
> .store+0xa0/0x100
> > [ 67.701723] [c0000007d25b7ae0] [c0000000003566e8]
> .sysfs_kf_write+0x88/0xb0
> > [ 67.701796] [c0000007d25b7b70] [c0000000003553b8]
> .kernfs_fop_write+0x178/0x260
> > [ 67.701881] [c0000007d25b7c10] [c0000000002ac3cc]
> .__vfs_write+0x3c/0x1c0
> > [ 67.701954] [c0000007d25b7cf0] [c0000000002ad584]
> .vfs_write+0xc4/0x230
> > [ 67.702027] [c0000007d25b7d90] [c0000000002aeef8]
> .SyS_write+0x58/0x100
> > [ 67.702101] [c0000007d25b7e30] [c00000000000bfec]
> system_call+0x38/0xfc
> >
> > Signed-off-by: Denis Kirjanov <k...@linux-powerpc.org <javascript:;>>
> >
> > v2: wrap powernv_cpufreq_throttle_check()
> > as suggested by Gautham R Shenoy
>
> Looks good otherwise.
>
> Reviewed-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com <javascript:;>>
>
> > ---
> > drivers/cpufreq/powernv-cpufreq.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/powernv-cpufreq.c
> b/drivers/cpufreq/powernv-cpufreq.c
> > index d3ffde8..112e0e2 100644
> > --- a/drivers/cpufreq/powernv-cpufreq.c
> > +++ b/drivers/cpufreq/powernv-cpufreq.c
> > @@ -647,8 +647,15 @@ static int powernv_cpufreq_target_index(struct
> cpufreq_policy *policy,
> > if (unlikely(rebooting) && new_index != get_nominal_index())
> > return 0;
> >
> > - if (!throttled)
> > + if (!throttled) {
> > + /*
> > + * we don't want to be preempted while
> > + * checking if the CPU frequency has been throttled
> > + */
> > + preempt_disable();
> > powernv_cpufreq_throttle_check(NULL);
> > + preempt_enable();
> > + }
> >
> > cur_msec = jiffies_to_msecs(get_jiffies_64());
> >
> > --
> > 1.8.3.1
> >
>
>
